Breast Cancer Genetics

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the main difference between hereditary and familial cancer?

Hereditary cancer has a higher risk of occurrence, familial cancer does not

Hereditary cancer is autosomal dominant, familial cancer is not

Hereditary cancer is always inherited, familial cancer is not

Hereditary cancer has a specific pattern of inheritance, familial cancer does not (correct)

What is the estimated percentage of colorectal and breast cancer that arise from inherited cancer susceptibility genes?

5% (correct)

10%

What is the name of the hypothesis proposed by Knudson in 1971?

Three-hit hypothesis

Two-hit hypothesis (correct)

Four-hit hypothesis

One-hit hypothesis

What type of cancer is associated with mutations in BRCA1 and BRCA2?

Breast and ovarian cancer Signup and view all the answers

What is the risk of a first-degree relative of a mutation carrier having the same mutation?

50% Signup and view all the answers

What is the term for the repair systems that correct DNA damage due to environmental mutations and mismatch bases incorporated during DNA replication?

DNA repair systems Signup and view all the answers

What is the name of the syndrome associated with inherited breast cancer?

Li-Fraumeni syndrome Signup and view all the answers

What is the term for the genes that increase the risk of cancer when mutated?

Cancer susceptibility genes Signup and view all the answers

What is the term for the process by which cells become cancerous due to the accumulation of mutations in DNA repair genes?

Mutator phenotype Signup and view all the answers

What is the name of the type of cancer that occurs when the fetus inherits a mutated chromosome 13 with a deleted RB locus?

Familial retinoblastoma Signup and view all the answers

What is the pattern of inheritance of Peutz Jeghers syndrome?

Autosomal dominant Signup and view all the answers

What is the approximate percentage of total colorectal cancers caused by Lynch syndrome?

2 to 5 % Signup and view all the answers

What is the main cause of melanoma?

Too much exposure to ultraviolet light Signup and view all the answers

What is the name of the syndrome that increases the risk of melanoma and pancreatic cancer?

Familial atypical multiple mole melanoma syndrome Signup and view all the answers

What is the name of the gene linked to familial cases of melanoma?

CDKN2A Signup and view all the answers

What is the age range in which people with Lynch syndrome are likely to develop bowel cancer?

Under the age of 50 Signup and view all the answers

What is the percentage of people with Lynch syndrome who will develop bowel cancer?

70 to 90 % Signup and view all the answers

What is the name of the syndrome that is inherited in an autosomal recessive pattern and increases the risk of bowel cancer?

MAP Signup and view all the answers

What percentage of breast cancer cases are considered hereditary?

5% Signup and view all the answers

What is the typical inheritance pattern for hereditary breast cancer?

Dominant Signup and view all the answers

Which gene is associated with Li-Fraumeni syndrome?

TP53 Signup and view all the answers

What is the major function of the BRCA1 and BRCA2 genes?

DNA repair Signup and view all the answers

What is the estimated lifetime risk of developing breast cancer for women with a BRCA1 or BRCA2 mutation?

45-90% Signup and view all the answers

Which of the following cancers is NOT associated with BRCA1 mutations?

Lung cancer Signup and view all the answers

Study Notes

Hereditary Breast Cancer

5% of breast cancers are hereditary, inherited in a dominant pattern, with early onset and often bilateral.
Having a sister diagnosed with breast cancer before age 40 increases the risk to 1 in 4.

BRCA1 and BRCA2

Located at 17q21 and 13q12, respectively.
Function: double-strand break repair of DNA.
Tumor suppressor genes.
Mutations: 45 to 90% of women with a mutation will develop breast cancer, and increase risk of ovarian cancer.
BRCA1 also increases risk of colon cancer, male breast cancer, and prostate cancer.

Other Mutations in Inherited Breast Cancer

Faults in TP53 and PTEN are rarer than BRCA1 and BRCA2 mutations.
TP53 gene normally controls cell division, causing breast cancer as part of Li-Fraumeni syndrome (<1% of all breast cancers).
Mutations in PTEN cause Cowden syndrome, increasing risk of breast cancer.

Li-Fraumeni Syndrome

Rare disorder that greatly increases the risk of developing several types of cancer, particularly in children and young adults.
Familial retinoblastoma occurs when a fetus inherits a chromosome 13 with a deleted RB locus.

Two-Hit Hypothesis by Knudson (1971)

Not mentioned in detail.

DNA Repair Genes

DNA repair systems correct DNA damage due to environmental mutations and mismatch bases.
Inherited defects of either system can result in increased frequency of cancer.

Hereditary Cancer Syndromes

When a cancer occurs as part of a hereditary cancer syndrome, the initial cancer-causing mutation is inherited through the germline and present in every cell of the body.
Estimated 5% of colorectal and breast cancer arise from an inherited cancer susceptibility gene.

Familial vs. Hereditary Cancer

Hereditary cancer: apparently autosomal dominant transmission, early age of onset, multiple primary cancers, and clustering of rare cancers.
Familial cancer: more cases of a specific type(s) of cancer within a family, but no specific pattern of inheritance.

Features Suggesting Inherited Cancer Susceptibility

Several close relatives with a common cancer.
Several close relatives with related cancers.
Two family members with the same rare cancer.
Unusually early age of onset.
Bilateral tumors in paired organs.
Synchronous or successive tumors.
Tumors in two different organ systems in one individual.

Breast and Ovarian Cancer

Not mentioned in detail.

Lynch Syndrome or Hereditary Non-Polyposis Colon Cancer (HNPCC)

Caused by mutations in MLH1, MSH2, MSH6, and PMS2 genes, involved in DNA mismatch repair.
Accounts for 2 to 5% of total colorectal cancers.
70 to 90% of people with Lynch syndrome will develop bowel cancer, mostly under the age of 50.
Increased risk of developing other cancers, including womb and ovarian cancer in women, stomach, small bowel, and gallbladder.

Peutz-Jeghers Syndrome

Linked to a mutation in STK11, inherited in an autosomal dominant pattern.
Increases the risk of bowel cancer and other types of cancer.
Patients with this syndrome also have melanin spots on lips and perioral regions.

Melanoma

Caused by too much exposure to ultraviolet light, from sunlight or artificial sources.
About 1 in 10 people (10%) with melanoma have a strong family history of the disease.

Familial Atypical Multiple Mole Melanoma Syndrome

Increases the risk of developing melanoma.
Characterized by more than 50 moles and at least one close relative with a melanoma diagnosis.
Some families with FAMMM are also at a higher risk of developing pancreatic cancer.

CDKN2A

Linked to familial cases of melanoma.
Participates in cell cycle regulation.
Its mutations are inherited in an autosomal dominant pattern.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the genetic aspects of breast cancer, including hereditary forms, inherited patterns, and associated genes like BRCA1 and BRCA2.