Cancer Epidemiology and Genetics Lecture Flashcards

A comprehensive set of vocabulary flashcards covering cancer genetics, hallmarks, stages of carcinogenesis, inherited syndromes, and environmental/occupational precursors based on the lecture transcript.

Cancer genes

Genes that are recurrently affected by genetic aberrations in cancers and contribute directly to the malignant behavior of cancer cells.

Oncogenes

Mutated or overexpressed versions of normal cellular genes (proto-oncogenes) that promote increased cell growth and are considered dominant.

Tumor suppressor genes

Genes that act as brakes on cellular proliferation or sense genomic damage; typically, both alleles must be silenced for transformation to occur.

Apoptosis-regulating genes

Genes that primarily influence cell survival; anti-apoptotic genes are often overexpressed in cancer, while pro-apoptotic genes are often under-expressed.

Driver Mutations

Usually acquired genetic alterations that are tightly clustered within cancer genes and directly effect cancer development.

Passenger Mutations

Acquired mutations occurring at random throughout the genome that are not related to cancer pathways.

Point Mutation

A change in a single nucleotide base pair in DNA that can activate proto-oncogenes (e.g., $RAS$) or disable tumor suppressors (e.g., $TP53$).

Gene arrangements

Genetic lesions produced by chromosomal translocations, inversions, or deletions that can result in proto-oncogene overexpression or fusion genes.

Burkitt lymphoma

A cancer often caused by a balanced reciprocal translocation between chromosomes $8$ and $14$, leading to overexpression of the $MYC$ gene.

Follicular lymphoma

A cancer caused by a balanced reciprocal translocation between chromosomes $14$ and $18$, leading to overexpression of the antiapoptotic gene $BCL2$.

Philadelphia (Ph) chromosome

A balanced reciprocal translocation between chromosomes $9$ and $22$ resulting in the $BCR-ABL$ fusion gene in Chronic Myeloid Leukemia.

Deletions

Recurrent loss of specific chromosomal regions, such as $13q14$ (site of the $RB$ gene) or $17p$ (site of the $TP53$ gene).

Gene Amplifications

The production of up to several hundred copies of a gene, such as $MYCN$ in neuroblastoma or $HER2$ ($ERBB2$) in breast cancer.

Aneuploidy

A number of chromosomes that is not a multiple of the haploid state ($23$ in humans), frequently resulting from mitotic checkpoint errors.

MicroRNAs (miRNAs)

Short, non-coding, single-stranded RNAs that function as negative regulators of genes by inhibiting translation post-transcriptionally.

Oncomirs

Specific miRNAs that produce cancer through overactivity, which reduces the activity of tumor suppressor proteins.

Epigenetics

Reversible, heritable changes in gene expression, such as DNA methylation or histone modifications, that occur without DNA mutation.

Tumor progression

The phenomenon where cancers become more aggressive and acquire greater malignant potential over time.

Initiation

The first stage of carcinogenesis involving irreversible, subtle genetic alterations that require cell division for fixation.

Promotion

A reversible stage of carcinogenesis involving changes in genome expression (not DNA structure), often mediated by hormones or chemicals.

Progression

An irreversible stage of carcinogenesis characterized by measurable or morphologically discernible alterations in cell genome structure.

Retinoblastoma

The most common intraocular malignancy of childhood, caused by the loss or inactivation of both alleles of the $RB1$ gene at $13q14.2$.

Knudson 2-hit hypothesis

A theory for autosomal dominant cancer syndromes stating that cancer results from two separate mutations (germline/somatic or somatic/somatic).

Familial adenomatous polyposis (FAP)

An autosomal dominant syndrome due to a germline mutation in the $APC$ gene ($5q21$), leading to thousands of colonic polyps.

Hereditary Breast and Ovarian Cancer Syndrome (HBOC)

A syndrome associated with $BRCA1$ and $BRCA2$ mutations, predisposing patients to malignancies in the breast, ovary, and fallopian tube.

BRCA1 and BRCA2

Tumor suppressor genes that code for proteins involved in repairing double-stranded DNA breaks via homologous recombination.

Xeroderma pigmentosum

An autosomal recessive syndrome of defective DNA repair involving genes used in nucleotide excision repair.

Li-Fraumeni syndrome

An autosomal dominant cancer syndrome involving various tumors caused by mutations in the $TP53$ gene.

Smoking

The most significant environmental risk factor for lung cancer, linked to $90\%$ of lung cancer deaths.

Alcohol consumption

An independent risk factor for cancers of the oropharynx, larynx, esophagus, breast, and liver.

Reproductive history

An environmental factor where lifelong exposure to estrogen, unopposed by progesterone, increases risk for endometrial and breast cancers.

Ionizing radiation

An environmental exposure linked to hematopoietic neoplasia (leukemia) and solid tumors like thyroid and lung carcinoma.

Precursor lesions

Disturbances of epithelial differentiation, such as squamous metaplasia or dysplasia, that carry an elevated risk of carcinoma.

Leukoplakia

A precursor lesion of the oral cavity, vulva, and penis that may progress to squamous cell carcinoma.

Arsenic

An occupational chemical byproduct of metal smelting linked to lung and skin carcinoma.

Asbestos

An occupational agent formerly used for fire resistance, linked to lung carcinoma and mesothelioma after a $20-30\,years$ latent period.

Benzene

A principal component of light oil used in solvents and detergents, linked to acute myeloid leukemia.

Vinyl chloride

A refrigerant and monomer for vinyl polymers linked to hepatic angiosarcoma.

Malignant mesothelioma

A neoplasm arising from mesothelial cells of serous cavities, often characterized by a thick rind of pleura or multiple nodules.

Barrett esophagus

A chronic inflammatory state caused by gastric acid reflux that is an etiologic agent for esophageal adenocarcinoma.