S-1 A drug that is being studied for its ability to enhance the effectiveness of fluorouracil and prevent gastrointestinal side effects caused by fluorouracil. It belongs to the family of drugs called antimetabolites.

S-phase fraction A measure of the percentage of cells in a tumor that are in the phase of the cell cycle during which DNA is synthesized. The S-phase fraction may be used with the proliferative index to give a more complete understanding of how fast a tumor is growing.

sacrum (SAY-krum) The large, triangle-shaped bone in the lower spine that forms part of the pelvis. It is made of 5 fused bones of the spine.

safingol A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called protein kinase C inhibitors.

saline A solution of salt and water.

saliva (suh-LIE-vuh) The watery fluid in the mouth made by the salivary glands. Saliva moistens food to help digestion and it helps protect the mouth against infections.

salivary gland (SAL-ih-vair-ee) A gland in the mouth that produces saliva.

salivary gland cancer (SA-lih-VAYR-ee gland KAN-ser) A rare cancer that forms in tissues of a salivary gland (gland in the mouth that makes saliva). Most salivary gland cancers occur in older people.

salpingo-oophorectomy (sal-PIN-go o-o-for-EK-toe-mee) Surgical removal of the fallopian tubes and ovaries.

salvage therapy Treatment that is given after the cancer has not responded to other treatments.

samarium 153 A radioactive substance used in cancer therapy.

saponin A substance found in soybeans and many other plants. Saponins may help lower cholesterol and may have anticancer effects.

saquinavir mesylate A drug that belongs to the family of drugs called protease inhibitors. It interferes with the ability of a virus to make copies of itself.

sarCNU A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called alkylating agents. Also called sarcosinamide nitrosourea.

sarcoid An inflammatory disease marked by the formation of granulomas (small nodules of immune cells) in the lungs, lymph nodes, and other organs. Sarcoid may be acute and go away by itself, or it may be chronic and progressive. Also called sarcoidosis.

sarcoidosis An inflammatory disease marked by the formation of granulomas (small nodules of immune cells) in the lungs, lymph nodes, and other organs. Sarcoidosis may be acute and go away by itself, or it may be chronic and progressive. Also called sarcoid.

sarcoma A cancer of the bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

sarcosinamide nitrosourea A substance that is being studied as a treatment for cancer. It belongs to the family of drugs called alkylating agents. Also called sarCNU.

sargramostim A substance that helps make more white blood cells, especially granulocytes, macrophages, and cells that become platelets. It is a cytokine that belongs to the family of drugs called hematopoietic (blood-forming) agents. Also called granulocyte-macrophage colony-stimulating factor (GM-CSF).

satraplatin A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called platinum analogs. Also called BMS-182751 and JM 216.

SB-715992 A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called mitotic inhibitors.

SC-70935 A substance that is being studied for its ability to stimulate the production of blood cells during chemotherapy. It belongs to the family of drugs called colony-stimulating factors. Also known as leridistim.

scalpel (SKAL-pul) A small, thin knife used for surgery.

scan A picture of structures inside the body. Scans often used in diagnosing, staging, and monitoring disease include liver scans, bone scans, and computed tomography (CT) or computerized axial tomography (CAT) scans and magnetic resonance imaging (MRI) scans. In liver scanning and bone scanning, radioactive substances that are injected into the bloodstream collect in these organs. A scanner that detects the radiation is used to create pictures. In CT scanning, an x-ray machine linked to a computer is used to produce detailed pictures of organs inside the body. MRI scans use a large magnet connected to a computer to create pictures of areas inside the body.

scanner In medicine, an instrument that takes pictures of the inside of the body.

SCF Stem cell factor. A drug that is being studied for its ability to increase the number of stem cells in the blood. It belongs to the family of drugs called hematopoietic cell growth factors. Also called ancestim and Stemgen.

SCH 54031 A drug used to treat hepatitis C infections. It is also being studied in the treatment and prevention of cancer. It is a cytokine that is modified in the laboratory. It belongs to the family of drugs called biological response modifiers. Also called PEG-Intron and PEG-interferon alfa-2b.

SCH 66336 An anticancer drug that belongs to the family of drugs called enzyme inhibitors. Also called lonafarnib.

SCH-58500 A drug that inhibits the growth of tumor cells that express the mutated p53 gene.

schedule (SKEH-jool) In clinical trials, the step-by-step plan for how patients are to be treated; for example, the drug or type of radiation therapy that is to be given, the method by which it is to be given, the amount of time between courses, and the total length of treatment.

Schiller test (SHIL-er) A test in which iodine is applied to the cervix. The iodine colors healthy cells brown; abnormal cells remain unstained, usually appearing white or yellow.

schizophrenia (SKIT-soh-FREE-nee-uh) A group of severe mental disorders in which a person has trouble telling the difference between real and unreal experiences, thinking logically, having normal emotional responses to others, and behaving normally in social situations. Symptoms include seeing, hearing, feeling things that are not there, having false ideas about what is taking place or who one is, nonsense speech, unusual behavior, lack of emotion, and social withdrawal.

Schwann cell A type of glial cell of the peripheral nervous system that helps separate and insulate nerve cells.

schwannoma (shwah-NO-ma) A tumor of the peripheral nervous system that arises in the nerve sheath (protective covering). It is almost always benign, but rare malignant schwannomas have been reported.

scientist A person who has studied science, especially one who is active in a particular field of investigation.

scintimammography A type of breast imaging test that is used to detect cancer cells in the breasts of some women who have had abnormal mammograms, or who have dense breast tissue. Scintimammography is not used for screening, or in place of a mammogram. In this test, a woman receives an injection of a small amount of a radioactive substance called technetium 99, which is taken up by cancer cells, and a gamma camera is used to take pictures of the breasts. Also called Miraluma test and sestamibi breast imaging.

scleroderma A chronic disorder marked by hardening and thickening of the skin. Scleroderma can be localized or it can affect the entire body (systemic).

screening Checking for disease when there are no symptoms.

screening mammogram X-rays of the breasts taken to check for breast cancer in the absence of signs or symptoms.

scrotum (SKRO-tum) In males, the external sac that contains the testicles.

Scutellaria barbata An herb that belongs to a group of herbs named the Scutellaria species or scullcap. Both the root and the above-ground part have been used to make herbal medicines. The root has been used in traditional Chinese medicine to treat lung cancer and other medical problems.

SDX-102 A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called antimetabolites. Also called alanosine.

SDX-105 A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called alkylating agents. Also called bendamustine.

sebum (SEE-bum) An oily substance produced by certain glands in the skin.

second primary cancer Refers to a new primary cancer in a person with a history of cancer.

second-line therapy Treatment that is given when initial treatment (first-line therapy) doesn’t work, or stops working.

second-look surgery Surgery performed after primary treatment to determine whether tumor cells remain.

secondary cancer A term that is used to describe either a new primary cancer or cancer that has spread from the place in which it started to other parts of the body.

sedative (SEH-duh-tiv) A drug used to calm a person down, relieve anxiety, or help a person sleep.

sedimentation rate The distance red blood cells travel in one hour in a sample of blood as they settle to the bottom of a test tube. The sedimentation rate is increased in inflammation, infection, cancer, rheumatic diseases, and diseases of the blood and bone marrow. Also called erythrocyte sedimentation rate.

sedoxantrone trihydrochloride A substance that is being studied as a treatment for cancer. It belongs to the family of drugs called DNA-intercalating compounds. Also called CI-958.

segmental cystectomy (sis-TEK-to-mee) The removal of cancer as well as some of the bladder tissue around the tumor. Sometimes called partial cystectomy.

segmental mastectomy (mas-TEK-toe-mee) The removal of cancer as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor. Usually some of the lymph nodes under the arm are also taken out. Also called partial mastectomy.

seizure (SEE-zhur) Convulsion; a sudden, involuntary movement of the muscles.

selection bias An error in choosing the individuals or groups to take part in a study. Ideally, the subjects in a study should be very similar to one another and to the larger population from which they are drawn (for example, all individuals with the same disease or condition). If there are important differences, the results of the study may not be valid.

selective estrogen receptor modulator (sel-EK-tiv ESS-tro-jen re-SEP-tor MOD-yew-lay-tor) SERM. A drug that acts like estrogen on some tissues but blocks the effect of estrogen on other tissues. Tamoxifen and raloxifene are SERMs.

selective serotonin reuptake inhibitor SSRI. A type of drug that is used to treat depression. SSRIs slow the process by which serotonin (a substance that nerves use to send messages to one another) is reused by nerve cells that make it. This increases the amount of serotonin available for stimulating other nerves.

selenium An essential dietary mineral.

self-esteem A feeling of self-worth, self-confidence, and self-respect.

sella turcica A depression of the bone at the base of the skull where the pituitary gland is located.

semaxanib (seh-MAX-uh-nib) A substance that has been studied in the treatment of cancer. It belongs to the families of drugs called angiogenesis inhibitors and tyrosine kinase inhibitors. Also called SU5416.

semen The fluid that is released through the penis during orgasm. Semen is made up of sperm from the testicles and fluid from the prostate and other sex glands.

seminal fluid (SEM-in-al) Fluid from the prostate and other sex glands that helps transport sperm out of the man’s body during orgasm. Seminal fluid contains sugar as an energy source for sperm.

seminal vesicle (SEM-in-al VES-ih-kul) A gland that helps produce semen.

seminal vesicle biopsy The removal of fluid or tissue with a needle from the seminal vesicles for examination under a microscope. The seminal vesicles are glands in the male reproductive tract that produce a part of semen.

seminoma (sem-in-O-ma) A type of cancer of the testicles. Seminomas may spread to the lung, bone, liver, or brain.

semiparasitic In botany, a plant that gets food from a host but also contains chlorophyll and is capable of photosynthesis.

semustine An anticancer drug that belongs to the family of drugs called alkylating agents.

senega root The root of an herb called Polygala senega. It has been used in some cultures to treat certain medical problems, including problems of the respiratory system.

senile keratosis A precancerous condition of thick, scaly patches of skin. Also called solar or actinic keratosis.

sensitivity When referring to a medical test, sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have the disease. No test has 100% sensitivity because some people who have the disease will test negative for it (false negatives).

sensor A device that responds to a stimulus, such as heat, light, or pressure, and generates a signal that can be measured or interpreted.

sensory Having to do with the senses.

sentinel lymph node The first lymph node to which cancer is likely to spread from the primary tumor. When cancer spreads, the cancer cells may appear first in the sentinel node before spreading to other lymph nodes.

sentinel lymph node biopsy Removal and examination of the sentinel node(s) (the first lymph node(s) to which cancer cells are likely to spread from a primary tumor). To identify the sentinel lymph node(s), the surgeon injects a radioactive substance, blue dye, or both near the tumor. The surgeon then uses a scanner to find the sentinel lymph node(s) containing the radioactive substance or looks for the lymph node(s) stained with dye. The surgeon then removes the sentinel node(s) to check for the presence of cancer cells.

sentinel lymph node mapping The use of dyes and radioactive substances to identify the first lymph node to which cancer is likely to spread from the primary tumor. Cancer cells may appear first in the sentinel node before spreading to other lymph nodes and other places in the body.

seocalcitol A substance that is being studied as a treatment for cancer. It belongs to the family of drugs called vitamin D analogs.

sepsis (SEP-sis) The presence of bacteria or their toxins in the blood or tissues.

septate (SEP-tate) An organ or structure that is divided into compartments.

septicemia Disease caused by the spread of bacteria and their toxins in the bloodstream. Also called blood poisoning.

sequential treatment One treatment after the other.

SERM Selective estrogen receptor modulator. A drug that acts like estrogen on some tissues but blocks the effect of estrogen on other tissues. Tamoxifen and raloxifene are SERMs.

serosa (seh-ROH-suh) The outer lining of organs and body cavities of the abdomen and chest, including the stomach. Also called serous membrane.

serotonin A hormone found in the brain, platelets, digestive tract, and pineal gland. It acts both as a neurotransmitter (a substance that nerves use to send messages to one another) and a vasoconstrictor (a substance that causes blood vessels to narrow). A lack of serotonin in the brain is thought to be a cause of depression. Also called 5-hydroxytryptamine.

serous (SEER-us) Having to do with serum, the clear liquid part of blood.

serous membrane The outer lining of organs and body cavities of the abdomen and chest, including the stomach. Also called serosa.

Sertoli-Leydig cell tumor of the ovary (sur-TOH-lee LY-dig TOO-mer) A rare type of ovarian tumor in which the tumor cells secrete a male sex hormone. This may cause virilization (the appearance of male physical characteristics in females). Also called androblastoma and arrhenoblastoma.

sertraline A drug that is used to treat depression. It belongs to the family of drugs called selective serotonin reuptake inhibitors (SSRIs). Also called Zoloft®.

serum The clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.

serum albumin The main protein in blood plasma. Low levels of serum albumin occur in people with malnutrition, inflammation, and serious liver and kidney disease.

serum glutamate pyruvate transaminase SGPT. An enzyme found in the liver and other tissues. A high level of serum glutamate pyruvate transaminase released into the blood may be a sign of liver damage, cancer, or other diseases. Also called alanine transferase.

serum glutamic-oxaloacetic transaminase SGOT. An enzyme found in the liver, heart, and other tissues. A high level of serum glutamic-oxaloacetic transaminase released into the blood may be a sign of liver or heart damage, cancer, or other diseases. Also called aspartate transaminase.

serum tumor marker test A blood test that measures the amount of substances called tumor markers (or biomarkers). Tumor markers are released into the blood by tumor cells or by other cells in response to tumor cells. A high level of a tumor marker may be a sign of cancer.

Serzone A drug used to treat depression. It belongs to the family of drugs called antidepressant agents. Also called nefazodone.

sesquiterpene lactone A substance found in some plants. Sesquiterpene lactones may have anti-inflammatory and anticancer effects. Plants containing sesquiterpene lactones have been used in some cultures to treat certain medical problems.

sestamibi breast imaging A type of breast imaging test that is used to detect cancer cells in the breasts of some women who have had abnormal mammograms, or who have dense breast tissue. Sestamibi breast imaging is not used for screening, or in place of a mammogram. In this test, a woman receives an injection of a small amount of a radioactive substance called technetium 99, which is taken up by cancer cells, and a gamma camera is used to take pictures of the breasts. Also called scintimammography and Miraluma test.

severe myelosuppression Severe reduction in the numbers of red blood cells, white blood cells, and platelets in the bone marrow. Severe myelosuppression is a side effect of some cancer treatments. Also called myeloablation.

SGN-00101 A substance that is being studied in the prevention of cancer. It belongs to the family of drugs called fusion proteins.

SGN-15 A substance that is being studied in the treatment of cancer. It combines a monoclonal antibody with the anticancer drug doxorubicin. Monoclonal antibodies are substances that are made in the laboratory and that can locate and bind to cancer cells. SGN-15 belongs to the family of drugs called antibody drug conjugates. Also called cBR96-doxorubicin immunoconjugate.

SGN-30 A monoclonal antibody that binds to cells that have the CD30 antigen on their surface, including Hodgkin’s disease cells and cells from anaplastic large cell lymphoma, and cutaneous T-cell lymphoma. SGN-30 is being studied in the treatment of cancer. It belongs to the family of drugs called monoclonal antibodies.

SGN-40 A monoclonal antibody that binds to cells that have the CD40 antigen on their surface, including cells from multiple myeloma, non-Hodgkin’s lymphoma, and chronic lymphocytic leukemia. SGN-40 is being studied in the treatment of cancer. It belongs to the family of drugs called monoclonal antibodies.

SGOT Serum glutamic-oxaloacetic transaminase. An enzyme found in the liver, heart, and other tissues. A high level of SGOT released into the blood may be a sign of liver or heart damage, cancer, or other diseases. Also called aspartate transaminase.

SGPT Serum glutamate pyruvate transaminase. An enzyme found in the liver and other tissues. A high level of SGPT released into the blood may be a sign of liver damage, cancer, or other diseases. Also called alanine transferase.

sham therapy An inactive treatment or procedure that is intended to mimic as closely as possible a therapy in a clinical trial. Also called placebo therapy.

shave biopsy (BY-ahp-see) A procedure in which a skin abnormality and a thin layer of surrounding skin are removed with a small blade for examination under a microscope. Stitches are not needed with this procedure.

sheep sorrel Rumex acetosella. A plant that has been used in some cultures to treat certain medical problems. It may have anticancer effects. Also called dock and sorrel.

Sheridan’s Formula A liquid that has been promoted as a treatment for a wide range of diseases, including cancer. The ingredients thought to be in Sheridan’s Formula have been tested, and none of them has been shown to be effective in treating any form of cancer. Sheridan’s Formula is not available in the United States. Also called Entelev, Cancell, Jim’s Juice, Crocinic Acid, JS–114, JS–101, 126–F, and Cantron.

shiitake mushroom Lentinus edodes. A dark oriental mushroom widely used as a food. Several anticancer substances have been found in shiitake mushrooms, including lentinan, which has been studied in Japan as a treatment for stomach and colorectal cancer.

Sho-saiko-to A Japanese formulation of seven Chinese herbs that is being studied as a treatment for cancer.

shunt In medicine, a passage that is made to allow blood or other fluid to move from one part of the body to another. For example, a surgeon may implant a tube to drain cerebrospinal fluid from the brain to the abdomen. A surgeon may also change normal blood flow by making a passage that leads from one blood vessel to another.

sialic acid (sy-A-lik) Any of a group of simple sugar molecules.

sialyl Tn-KLH A vaccine composed of a substance that enhances immunity plus an antigen found on some tumors of the colon, breast, lung, ovary, pancreas, and stomach.

side effect A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

side-to-end coloanal anastomosis A surgical procedure in which the side of the colon is attached to the anus after the rectum has been removed. A section of the colon about 2 inches long is formed into a mini-pouch in order to replace the function of the rectum and store stool until it can be eliminated. This procedure is similar to the J-pouch coloanal anastomosis but a much smaller pouch is formed.

sideropenic dysphagia A disorder marked by anemia caused by iron deficiency, and a web-like growth of membranes in the throat that makes swallowing difficult. Having sideropenic dysphagia may increase the risk of developing esophageal cancer. Also called Paterson-Kelly syndrome and Plummer-Vinson syndrome.

SIDS Sudden infant death syndrome. The sudden and unexpected death of a healthy child who is younger than one year old, usually during sleep. The cause of SIDS is not known. Also called crib death.

sigmoid colon (SIG-moyd KO-lun) The S-shaped section of the colon that connects to the rectum.

sigmoidoscope (sig-MOY-da-skope) A thin, lighted tube used to view the inside of the colon.

sigmoidoscopy (sig-MOY-DAHS-kuh-pee) Inspection of the lower colon using a thin, lighted tube called a sigmoidoscope. Samples of tissue or cells may be collected for examination under a microscope. Also called proctosigmoidoscopy.

signal transduction inhibitor A drug that may prevent the ability of cancer cells to multiply quickly and invade other tissues.

signet ring cell carcinoma A highly malignant type of cancer typically found in glandular cells that line the digestive organs. The cells resemble signet rings when examined under a microscope.

significant In statistics, describes a mathematical measure of difference between groups. The difference is said to be significant if it is greater than what might be expected to happen by chance alone. Also called statistically significant.

SIL Squamous intraepithelial lesion. A general term for the abnormal growth of squamous cells on the surface of the cervix. The changes in the cells are described as low grade or high grade, depending on how much of the cervix is affected and how abnormal the cells appear.

sildenafil A substance that is used to treat erectile dysfunction. Sildenafil relaxes the smooth muscle of the penis to allow increased blood flow and erection. It belongs to the family of drugs called phosphodiesterase inhibitors. Also called Viagra.

silicon phthalocyanine 4 (SIH-lih-KON THAH-loh-SY-uh-NEEN) A drug that is being studied in the treatment of cancer. When absorbed by cancer cells and exposed to light, it becomes active and kills the cancer cells. It belongs to the family of drugs called photodynamic therapy agents.

silicone A synthetic gel that is used as an outer coating on breast implants and as the inside filling of some implants.

Silybum marianum A plant that has been used in some cultures to treat certain medical problems, including stomach, liver, and gallbladder disorders. The active extract of Silybum marianum seeds is called silymarin. It is being studied in the prevention of liver damage caused by some cancer treatments. Also called milk thistle.

silymarin A substance obtained from milk thistle seeds that is being studied in the prevention of liver damage caused by certain cancer treatments.

simian virus 40 (SIH-mee-un VY-rus…) SV40. A virus that infects some types of monkeys. It may also infect humans, and was found in some polio vaccines tested in the early 1960s. Although the virus has been shown to cause cancer in laboratory animals, there is no evidence that it causes cancer in people.

simple mastectomy Removal of the breast. Also called total mastectomy.

simple nephrectomy (neh-FREK-tuh-mee) Surgery to remove one kidney.

simulation In cancer treatment, a process used to plan radiation therapy so that the target area is precisely located and marked.

single blind study A type of clinical trial in which only the doctor knows whether a patient is taking the standard treatment or the new treatment being tested. This helps prevent bias in treatment studies.

single nucleotide polymorphism SNP. The most common type of change in DNA (molecules inside cells that carry genetic information). An SNP occurs when a single nucleotide (building block of DNA) is replaced with another. These changes may cause disease, and may affect how a person reacts to bacteria, viruses, drugs, and other substances.

single-photon emission computed tomography SPECT. A special type of computed tomography (CT) scan in which a small amount of a radioactive drug is injected into a vein and a scanner is used to make detailed images of areas inside the body where the radioactive material is taken up by the cells. SPECT can give information about blood flow to tissues and chemical reactions (metabolism) in the body.

siplizumab A monoclonal antibody that is being studied in the treatment of certain lymphoproliferative disorders and psoriasis. Also called MEDI-507.

sirolimus A drug used to help prevent the body from rejecting organ and bone marrow transplants. It is also being studied as a treatment for cancer. Sirolimus belongs to the family of drugs called immunosuppressants. It was previously called rapamycin.

SIRS Systemic inflammatory response syndrome. A serious condition in which there is inflammation throughout the whole body. It may be caused by a severe bacterial infection (sepsis), trauma, or pancreatitis. It is marked by fast heart rate, low blood pressure, low or high body temperature, and low or high white blood cell count. The condition may lead to multiple organ failure and shock.

SJG-136 A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called DNA cross-linking agents.

Sjögren’s syndrome (SHOH-grinz SIN-drohm) An autoimmune disease that affects the tear glands and salivary glands, and may affect glands in the stomach, pancreas, and intestines. The disease causes dry eyes and mouth, and may cause dryness in the nose, throat, air passages, skin, and vagina. It may also cause inflammation in the joints, muscles, and skin; pneumonia; tingling in the fingers and toes; and fatigue. It often occurs with rheumatoid arthritis or other connective tissue diseases.

skeletal (SKEH-leh-tul) Having to do with the skeleton (bones of the body).

skeleton The framework that supports the soft tissues of vertebrate animals and protects many of their internal organs. The skeletons of vertebrates are made of bone and/or cartilage.

skin cancer (skin KAN-ser) Cancer that forms in tissues of the skin. When cancer forms in cells that make pigment, it is called melanoma. When cancer forms in cells that do not make pigment it may begin in basal cells (small, round cells in the base of the outer layer of skin) or squamous cells (flat cells that form the surface of the skin). Both types of skin cancer usually occur in skin that has been exposed to sunlight, such as the skin on the face, neck, hands, and arms.

skin graft Skin that is moved from one part of the body to another.

skin patch A bandage-like patch that releases medicine into the body through the skin. The medicine enters the blood slowly and steadily.

skin stimulation The process of applying pressure, friction, temperature change, or chemical substances to the skin to lessen or block a feeling of pain.

skin test A test for an immune response to a compound by placing it on or under the skin.

SLE Systemic lupus erythematosus. A chronic, inflammatory, connective tissue disease that can affect many organs including the joints, skin, heart, lungs, kidneys, and nervous system. It is marked by many different symptoms; however, not everyone with SLE has all of the symptoms. Also called lupus.

slippery elm Ulmus fulva or Ulmus rubra. The inner bark of this plant has been used in some cultures to treat certain medical problems. It may have antioxidant effects. Also called gray elm, Indian elm, red elm, and sweet elm.

small cell lung cancer An aggressive (fast-growing) cancer that usually forms in tissues of the lung and spreads to other parts of the body. The cancer cells look small and oval-shaped when looked at under a microscope. Also called oat cell cancer.

small intestine (in-TES-tin) The part of the digestive tract that is located between the stomach and the large intestine.

small intestine cancer (smawl in-TES-tin KAN-ser) A rare cancer that forms in tissues of the small intestine (the part of the digestive tract between the stomach and the large intestine). The most common type is adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). Other types of small intestine cancer include sarcoma (cancer that begins in connective or supportive tissue), carcinoid tumor (a slow-growing type of cancer), gastrointestinal stromal tumor (a type of soft tissue sarcoma), and lymphoma (cancer that begins in immune system cells).

small lymphocytic lymphoma (LIM-foh-SI-tik lim-FOH-muh) An indolent (slow-growing) type of B-cell non-Hodgkin’s lymphoma marked by swollen lymph nodes that usually occurs in people older than 50 years. It is very similar to a form of leukemia called chronic lymphocytic leukemia (CLL). Also called well-differentiated lymphocytic lymphoma.

smoldering leukemia A disease in which the bone marrow does not function normally. Also called preleukemia and myelodysplastic syndrome.

smoldering myeloma A very slow-growing type of myeloma in which abnormal plasma cells (a type of white blood cell) make too much of a single type of monoclonal antibody (a protein). This protein builds up in the blood or is passed in the urine. Patients with smoldering myeloma usually have no symptoms, but need to be checked often for signs of progression to fully developed multiple myeloma.

SnET2 An anticancer drug that is also used in cancer prevention. It belongs to the family of drugs called photosensitizing agents. Also called tin ethyl etiopurpurin.

SNP Single nucleotide polymorphism. The most common type of change in DNA (molecules inside cells that carry genetic information). An SNP occurs when a single nucleotide (building block of DNA) is replaced with another. These changes may cause disease, and may affect how a person reacts to bacteria, viruses, drugs, and other substances.

SNX 111 A drug used in the treatment of chronic pain. Also called ziconotide.

soblidotin A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called tubulin inhibitors. Also called TZT-1027.

social service (SOH-shul SER-vis) A community resource that helps people in need. Services may include help getting to and from medical appointments, home delivery of medication and meals, in-home nursing care, help paying medical costs not covered by insurance, loaning medical equipment, and housekeeping help.

social support (SOH-shul suh-PORT) A network of family, friends, neighbors, and community members that is available in times of need to give psychological, physical, and financial help.

social worker A professional trained to talk with people and their families about emotional or physical needs, and to find them support services.

sodium A mineral needed by the body to keep body fluids in balance. Sodium is found in table salt and in many processed foods. Too much sodium can cause the body to retain water.

sodium borocaptate BSH. A substance used in a type of radiation therapy called boron neutron capture therapy. Sodium borocaptate is injected into a vein and becomes concentrated in tumor cells. The patient then receives radiation treatment with atomic particles called neutrons. The neutrons react with the boron in sodium borocaptate and make radioactive particles that kill the tumor cells without harming normal cells.

sodium salicylate A drug that belongs to the family of drugs called nonsteroidal anti-inflammatory drugs. Sodium salicylate may be tolerated by people who are sensitive to aspirin.

sodium sulfite A chemical used in photography, paper making, water treatment, and for other purposes.

sodium thiosulfate (SO-dee-um thye-oh-SUL-fate) A substance that is used in medicine as an antidote to cyanide poisoning and to decrease side effects of the anticancer drug cisplatin.

soft diet A diet consisting of bland foods that are softened by cooking, mashing, pureeing, or blending.

soft palate (PAL-et) The back, muscular (not bony) part of the roof of the mouth.

soft tissue Refers to muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body.

soft tissue sarcoma (…TIH-shoo sar-KOH-muh) A cancer that begins in the muscle, fat, fibrous tissue, blood vessels, or other supporting tissue of the body.

solar keratosis A precancerous condition of thick, scaly patches of skin. Also called actinic or senile keratosis.

solid tumor An abnormal mass of tissue that usually does not contain cysts or liquid areas. Solid tumors may be benign (not cancerous), or malignant (cancerous). Different types of solid tumors are named for the type of cells that form them. Examples of solid tumors are sarcomas, carcinomas, and lymphomas. Leukemias (cancers of the blood) generally do not form solid tumors.

somatic cell Any of the body cells except the reproductive (germ) cells.

somatic mutation An alteration in DNA that occurs after conception. Somatic mutations can occur in any of the cells of the body except the germ cells (sperm and egg) and therefore are not passed on to children. These alterations can (but do not always) cause cancer or other diseases.

somatostatin receptor scintigraphy SRS. A type of radionuclide scan used to find carcinoid and other types of tumors. In SRS, radioactive octreotide, a drug similar to somatostatin, is injected into a vein and travels through the bloodstream. The radioactive octreotide attaches to tumor cells that have receptors for somatostatin. A radiation-measuring device detects the radioactive octreotide, and makes pictures showing where the tumor cells are in the body. This procedure is also called an octreotide scan.

somnolence syndrome (SOM-no-lens) Periods of drowsiness, lethargy, loss of appetite, and irritability in children following radiation therapy treatments to the head.

sonogram (SON-o-gram) A computer picture of areas inside the body created by bouncing high-energy sound waves (ultrasound) off internal tissues or organs. Also called an ultrasonogram.

sorafenib A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called raf kinase inhibitors. Also called BAY 43-9006 and Nexavar.

sorivudine An antiviral drug that is being studied as a treatment for herpesvirus. It belongs to the family of drugs called nucleic acid synthesis inhibitors.

sorrel Rumex acetosella. A plant that has been used in some cultures to treat certain medical problems. It may have anticancer effects. Also called sheep sorrel and dock.

soy Glycine max. A plant of Asian origin that produces beans used in many food products. Soy products contain isoflavones (estrogen-like substances) that are being studied for the prevention of cancer, hot flashes that occur with menopause, and osteoporosis (loss of bone density). Soy products in the diet may lower cholesterol levels and reduce the risk of heart disease. Also called soya and soybean.

soya (SOY-uh) Glycine max. A plant of Asian origin that produces beans used in many food products. Soy products contain isoflavones (estrogen-like substances) that are being studied for the prevention of cancer, hot flashes that occur with menopause, and osteoporosis (loss of bone density). Soy products in the diet may lower cholesterol levels and reduce the risk of heart disease. Also called soy and soybean.

soybean Glycine max. A plant of Asian origin that produces beans used in many food products. Soy products contain isoflavones (estrogen-like substances) that are being studied for the prevention of cancer, hot flashes that occur with menopause, and osteoporosis (loss of bone density). Soy products in the diet may lower cholesterol levels and reduce the risk of heart disease. Also called soy and soya.