Biology of Tumor Growth Lecture Notes

Vocabulary flashcards covering the biology of tumor growth, metastasis mechanism, epidemiology, and specific cancer risk factors based on the lecture notes.

Growth Fraction

The ratio of cell proliferation to cell loss that influences the kinetics of tumor growth.

Angiogenesis

A process induced by tumors to ensure oxygen and nutrient supply and facilitate distant spreading of neoplastic cells.

VEGF & FGF

Growth factors that play a role in inducing tumor angiogenesis.

Tumor Progression

The orderly progression from a pre-neoplastic lesion to a benign tumor and ultimately to invasive cancer.

Genetic Instability

A condition that yields an increased rate of random, spontaneous mutations during clonal expansion.

Cadherin molecules

Proteins whose loss leads to the detachment of tumor cells from each other during the cellular basis of metastasis.

Matrix metalloproteases

Proteolytic enzymes secreted by tumor cells to degrade the extracellular matrix ($ECM$).

Autocrine motility factor

A cytokine that facilitates the locomotion of tumor cells through the basement membrane and into vessels.

Intravasation

The process of tumor cells moving through the basement membrane and into blood or lymphatic vessels.

Extravasation

The step in metastasis where tumor cells exit a vessel to form a metastatic deposit.

Organ Tropism

A phenomenon where neoplastic cells show a selective site for metastasis not explained by natural pathways of drainage.

Immunosurveillance

The recognition and destruction of tumor cells by the immune system.

Tumor-Specific Antigens (TSA’s)

Antigens recognized by cytotoxic T cells to lyse tumor cells.

Tumor-Associated Antigens (TAA’s)

Antigens found on tumor cells that help the immune system identify them, distinguished from $TSA$'s.

Natural Killer (NK) Cells

Lymphocytes that can lyse tumor cells without recognizing specific tumor-specific antigens.

LAK (lymphocyte activated killer cell)

A cell type activated by $IL-1$ that can lyse tumor cells independently of $TSA$ recognition.

Epidemiology

The study of identifying common factors contributing to the spread, growth, or development of a disease.

Carcinogen

An agent capable of causing cancer.

Geographical/Environmental Factors

Variables explaining why lung cancer is $2\times$ greater in the U.S. than Japan or why skin cancer deaths vary greatly between New Zealand and Iceland.

Adenoma of the colon

A benign neoplasm that is considered an acquired pre-neoplastic disorder.

Inherited cancer syndromes

Malignancies where inheritance of a single identified mutant gene greatly increases the risk of developing a neoplasm.

Childhood retinoblastoma

An inherited cancer syndrome caused by a mutation in the $Rb$ gene.

Familial adenomatous polyposis coli

An inherited cancer syndrome associated with a mutation in the $APC$ gene.

Li-Fraumeni syndrome

A hereditary condition characterized by an increased risk of neoplasm due to a $p53$ mutation.

Familial Cancers

An increased incidence of cancer in genetic relatives without a consistent link to a specific genetic mutation.

High-risk HPV strains

Strains of Human Papilloma Virus containing DNA sequences that degrade the $p53$ gene product, leading to cervical or oral carcinoma.

Epstein-Barr Virus (EBV)

A virus that infects epithelial cells and B lymphocytes; it is associated with mononucleosis and Burkitt's lymphoma.

Hepatitis B Virus (HBV)

A virus strongly associated with hepatocellular carcinoma through chronic liver damage and regenerative hyperplasia.

Helicobactor pylori

A bacterium associated with chronic gastritis, gastric carcinomas, and B-cell lymphomas of the stomach.

Prostate Specific Antigen (PSA)

A substance secreted by prostate epithelium used in screening; levels above $4\text{ ng/ml}$ may indicate hypertrophy or cancer.

Gleason score

A histological grading system for prostate carcinoma with a range of $2-10$.

Initiation

The exposure of cells to a carcinogenic agent that elicits a permanent DNA mutation.

Promotion

The induction of a neoplasm in initiated cells following exposure to a second carcinogen.

Angiostatin

A protein that acts as an inhibitor of angiogenesis and is the focus of current immunotherapy research.

Adoptive immunotherapy

A potential future treatment in which cytotoxic T cells are used to recognize and lyse tumor cells.

Adult Cancer Demographics

The observation that carcinomas present more frequently in individuals older than $55\text{ yr}$.

Prostate Carcinoma Treatment Complications

Common side effects of surgery or radiation for prostate cancer, including impotence and incontinence.

Saw palmetto

An herb used as adjunct therapy for prostate carcinoma that inhibits $DHT$ synthesis.

Genistein

A soy derivative that decreases angiogenesis and blocks growth factor receptors.

Lycopenes

Anti-oxidant compounds used as an adjunct therapy in the management of prostate carcinoma.

Acquired pre-neoplastic disorders

Non-neoplastic or benign conditions, such as liver cirrhosis or ulcerative colitis, that have a defined link to malignancy.

Aflatoxin

A naturally occurring carcinogen mentioned as a chemical initiator.

Direct alkylating agents

A class of chemical initiators involved in the process of carcinogenesis.

Promoters (Examples)

Agents such as dietary fats and estrogens that can trigger the cell cycle to induce a neoplasm.

Common Metastatic Sites

The specific organs most targeted for dissemination, identified as the liver, lung, bone, and brain.