Cancer Genetics

Flashcards covering key vocabulary and concepts related to cancer genetics.

Neoplasm

A mass of cells that undergo uncontrolled proliferation, also known as a tumor or cancer.

Carcinogenesis

The process of cancer development.

Carcinogen

Substances or mutagens that can produce cancer.

Tumor-Suppressor Gene

Genes that normally inhibit cellular proliferation, e.g. RB1, APC, p53.

Proto-Oncogene

Genes that normally promote cellular proliferation.

Oncogene

Proto-oncogenes that are activated by mutations to produce dominant GoF phenotypes and transform normal cells into cancer cells

Benign Tumor

A tumor that grows as a compact mass and remains at its site of origin.

Malignant Tumor

A tumor that invades surrounding tissues and can spread to distal sites, known as metastasis.

Knudson’s Two-Hit Model

A hypothesis stating that tumorigenesis occurs when a cell acquires two mutations in tumor suppressor genes.

Signaling Pathways

Biological pathways that regulate cell growth and division, crucial in understanding tumorigenesis.

Genomic Instability

An abnormal condition leading to increased mutations throughout the genome, often activating oncogenes or deactivating tumor-suppressor genes.

Telomerase

An enzyme that allows tumor cells to avoid senescence by maintaining telomere length, promoting immortality.

GWAS (Genome-Wide Association Studies)

Studies designed to show allele frequencies at many loci in disease cases compared to unaffected controls.

Loss of Heterozygosity (LOH)

A condition resulting from the deletion of one allele of a gene, often observed in tumor cells.

DNA Repair Genes

Genes that help maintain chromosome integrity and repair DNA, e.g. BRCA1, BRCA2.

Neoplasia

New growth

Sporadic (non inherited) case

Both alleles must be mutated → mostly unilateral

Familial (inherited) case

Children inherit a mutated allele in germline from one parent and likely acquire a second somatic mutation to initiate second tumerogensis → mostly bilateral

Retroviruses

RNA viruses that cause cancer

RAS signalling

Mutations in RAS gene are found in 30% of cancers, RAS protein in a G-proteinthat transmits signals for cell growth and division.

Chronic Myelogenous Leukemia (CML)

mostly caused by a reciprocal translocation between chromosome 22 and the long arm of chromosome 9 (Philadelphia chromosome/translocation)

Xeroderma Pigmentosum (XP)

Autosomal recessive disorder resulting in early onset of skin cancer caused by a defective NER systemthat repairs DNA damage caused by UV light.

SNP microarray

A technique used to measure the expression levels of many genes simultaneously or to genotype multiple regions of a genome. It allows for the detection of genetic variations across individuals.

Single nucleotide polymorphism (SNP)

Not a mutation or a cause of a mutation but used as a marker to see where a mutation is