Cancer Biology, Carcinogenesis, Metastasis, and Staging Flashcards

A set of vocabulary flashcards defining key concepts in cancer biology, including tumor suppressor pathways, carcinogenesis steps, metastatic mechanics, and clinical grading and staging systems.

Tumor Suppressor Genes

Normal genes in the body that stop or suppress tumor formation by inhibiting cell division and promoting apoptosis, especially in mutated cells.

Loss of Function Mutation

A mutation that inactivates a tumor suppressor gene, preventing it from suppressing proliferation or activating apoptosis, thereby allowing uncontrollable cell division.

p53 Gene

A tumor suppressor gene located on chromosome 17 named after its molecular mass; defects in p53 are among the most common gene defects found in over half of human tumors.

p21

A downstream protein activated by p53 that stops cell growth by halting the cell cycle at the G1 phase checkpoint to allow for DNA repair.

GAD45

A downstream molecule activated by p53 that assists in DNA repair, or helps trigger apoptosis if DNA repair fails.

Bax

A pro-apoptotic protein activated by p53 when DNA repair fails, initiating apoptosis to remove damaged cells.

BRCA1

An autosomal tumor suppressor gene on chromosome 13 involved in double-stranded DNA repair; mutations confer a 50% to 85% risk of breast cancer and an increased risk of ovarian cancer.

BRCA2

An autosomal tumor suppressor gene on chromosome 17 involved in double-stranded DNA repair, closely associated with inherited forms of breast cancer.

Carcinogenesis

The multi-step process of cancer formation, requiring initial DNA damage followed by cell growth, growth factor release, rapid division, and cancer progression.

Initiation (in Carcinogenesis)

The initial step of cancer formation where exposure to damaging agents (such as radiation, X-rays, gamma rays, or sunlight) causes DNA mutations that promote cell growth.

Anaplasia

The degree to which cancer cells lose their normal cell structure, appearance, and organizational phenotype through rapid division.

Metastasis

The process by which cancer cells break free from their primary origin site, navigate through tissues and blood or lymph vessels, and establish secondary tumor colonies in distant sites.

Angiogenesis

The process in which tumor cells secrete growth factors to stimulate the formation of new blood vessels, supplying the growing tumor with oxygen and nutrients.

Collagenases

Enzymes secreted by cancer cells that degrade collagen fibers in the basement membrane, allowing cells to detach, squeeze through, and enter the extracellular matrix.

Tumor Cell Embolus

A cluster of tumor cells (often bound with platelets) that has detached and is freely floating within a blood vessel rather than being fixed to the vessel wall.

Tumor Markers

Specific enzymes, genes, or transcription patterns expressed by cells that allow clinicians to genetically identify the original tissue location of a metastatic cancer.

Tumor Grading

A categorization system based on the microscopic, histological appearance and degree of anaplasia of tumor cells.

Grade 1 Tumor

A low-grade tumor classification where the organization and appearance of cells under microscopic histology remain close to normal.

Grade 3 Tumor

A high-grade tumor classification marked by severe anaplasia, rapid cell spreading, and a distinct histological appearance completely different from normal cells.

Tumor Staging

A system (Stages 1 through 4) that describes the size, location, and extent of spread of a tumor throughout the body.

Stage 1 Cancer

An early stage of cancer where the tumor is small and remains localized strictly within its organ of origin.

Stage 2 Cancer

A stage where the tumor has grown larger but has not yet spread to nearby tissues or outside its original organ.

Stage 3 Cancer

A progression stage where a large tumor has begun spreading into neighboring tissues and the regional lymphatic system (lymph nodes).

Stage 4 Cancer

An advanced stage of cancer in which tumor cells have metastasized to distant organs and established new sites of disease.

Cachexia

A physical condition characterized by a malnourished, body-wasting appearance caused by highly metabolic cancer cells depleting the patient's nutrients.