Introduction to Cancer and Tumor Biology

Vocabulary flashcards covering key terms and concepts from the lecture notes on Introduction to Cancer and Tumor Biology, including mutation types, proto-oncogenes, viral mechanisms, cancer phases, tumor markers, and tumor characteristics.

Mutagens

Agents that cause mutations.

Carcinogens

A type of mutagen that specifically causes mutations leading to cancer.

Common Mutation Type (Cancer)

Substitution, which can alter a cell cycling protein, often removing 'brakes' on cell cycling.

Proto-oncogenes

Normal genes whose function is to regulate mitosis.

Epidermal Growth Factor (EGF)

A growth factor that promotes the growth of the epidermal layer and increases mitosis, typically in response to wounds.

Cyclins

Enzymes that regulate the progression of a cell through different stages of the cell cycle.

Overexpression (Proto-oncogenes)

Pathological alteration due to gene duplication, leading to excessive regulation of mitosis.

v-onc (viral oncogene)

A host proto-oncogene accidentally picked up and carried within viral DNA.

c-onc (cellular oncogene)

A viral oncogene (v-onc) that has inserted into a new host's DNA, inappropriately introducing a growth-regulating factor.

Human Papillomavirus (HPV)

An example of a virus known to insert proto-oncogenes (v-oncs) into host cells, contributing to cancer.

Direct Mechanism (Viral Oncogene Activity)

A process where a virus acquires a host proto-oncogene, creating a v-onc, which then inserts into a new host's genome as a c-onc, initiating cancer.

Indirect Mechanism (Viral Oncogene Activity)

Extensive cell lysis by viral infection triggering rapid tissue regeneration, making cells more susceptible to mutations during increased mitosis.

Chronic Viral Hepatitis

An example of an indirect mechanism where continuous liver regeneration due to viral damage increases the risk of liver cancer.

Initiation Phase (Cancer)

The first phase where an initial DNA mutation occurs and is not repaired, becoming irreversible, laying the groundwork for cancer.

Promotion Phase (Cancer)

The second phase characterized by cell proliferation and the generation of a tumor, influenced by genetic predisposition or environmental factors.

Tumor

A cellular mass; in cases like leukemia, it refers to leukemic cells circulating in the blood.

Altered Cell Surface Antigens

Changes in 'self' markers on cancer cell surfaces, some being specific to certain cancers.

Defective Fibronectin

A protein responsible for attaching cells to the extracellular matrix; when defective in cancer cells, it leads to loosened, unanchored and identity-losing cells.

Proteases (Cancer)

Enzymes released by cancer cells that degrade connective tissue, loosen cells, damage blood vessel endothelium, and inappropriately activate plasminogen into plasmin.

Plasmin

An anti-clotting factor; inappropriate activation by cancer cell proteases can lead to systemic bleeding issues and facilitate metastasis by allowing cells to enter the bloodstream.

Decrease in Gap Junctions

A reduction in connections between adjacent cells, leading to isolation of cancer cells, which promotes further mitosis as the cell interprets it as a need to divide.

Ectopic Hormones

Hormones produced inappropriately by cancer cells from non-endocrine tissues (e.g., ACTH from lung cancer).

Alpha-fetoprotein

An inappropriately released antigen protein, normally found in fetal cells, indicating dedifferentiation and rapid mitosis in cancer.

Philadelphia Chromosome

A specific chromosomal translocation (t(9;22)) found in 90-95% of CML patients, leading to overactivation of proto-oncogenes.

Progression Phase (Cancer)

The stage where tumors are classified as either benign or malignant, characterized by their growth, differentiation, and metastatic potential.

Benign Tumors

Tumors with relatively well-differentiated cells, low growth rate, usually encapsulated, do not metastasize, and have a very low mortality chance, but can cause problems by compression.

Malignant Tumors

Tumors displaying anaplasia (undifferentiated cells), rapid uncontrolled growth, not encapsulated (invasive), highly metastatic, and have high metabolic demands.

Anaplasia

The condition of malignant tumor cells being undifferentiated, lacking specialized characteristics and resembling embryonic or stem cells.

Ischemia (Tumors)

Lack of oxygen and nutrients within a rapidly growing malignant tumor due to its high metabolic demand outstripping the blood supply.

Tumor Angiogenesis Factor

A factor released by malignant tumors that stimulates the growth of new blood vessels (angiogenesis) to supply the tumor with oxygen and nutrients.

Angiogenesis

The process of new blood vessel growth, stimulated by malignant tumors to overcome ischemia and fuel rapid growth.

Metastasis

The spread of cancer cells from the primary tumor to other parts of the body.

Hemogenic Spread

Metastasis of cancer cells via the bloodstream.

Lymphatic Spread

Metastasis of cancer cells via the lymphatic system, moving from lymph node to lymph node.

Organ Tropism

An affinity of cancer cells for specific distant organs during metastasis (e.g., breast cancer to bone).

Cachexia (Wasting Syndrome)

A severe wasting of body mass, often seen in cancer patients, driven by factors like Tumor Necrotic Factor (TNF).

Tumor Necrotic Factor (TNF) and Cachexia

A factor released by malignant tumors that reduces insulin levels, induces a 'fasting state,' breaks down stored nutrients, and suppresses appetite, fueling tumor growth and contributing to severe body wasting.