Inherited Mutations and Tumor Suppressor Genes

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Questions and Answers

What role do inherited mutations play in most cancer cases?

They are the primary cause of cancer.

They are a major factor in most cases.

They only affect specific types of cancer.

They generally do not significantly contribute. (correct)

What method can help gauge the impact of inheritance on tumor formation?

Assessing the age of cancer diagnosis in the population.

Estimating the average lifespan of cancer patients.

Evaluating the likelihood of identical twins developing the same cancer. (correct)

Analyzing the types of cancer prevalent in families.

Which statement is accurate regarding inherited cancer syndromes?

They are the main cause of all cancer types.

Their study has little relevance to cancer development.

They have taught us about malfunctioning genes and cancer. (correct)

They can be completely eliminated through gene therapy.

In what way are identical twins relevant to cancer research?

Their cancer development can indicate genetic factors. Signup and view all the answers

What can be concluded about most inherited mutations related to cancer?

They are not commonly associated with the disease. Signup and view all the answers

How does the study of cancer mutations enhance our understanding of cancer?

It helps identify malfunctioning genes that could lead to cancer. Signup and view all the answers

Why might it be important to study inherited cancer syndromes?

They contribute to our understanding of genetic cancer risks. Signup and view all the answers

What is one misconception about the role of inherited mutations in cancer?

They play a crucial role in the majority of cancer cases. Signup and view all the answers

What is a significant reason why cancer cells are more sensitive to drugs and radiation than normal cells?

Normal cells enter a senescence program after genetic damage. Signup and view all the answers

Which tumor-suppressor gene is often disabled in human cancers and is involved in the senescence pathway?

INK4a Signup and view all the answers

What role does the protein p16, encoded by the INK4a gene, serve in the body?

It inhibits cyclin-dependent kinases. Signup and view all the answers

Which consequence is directly associated with the loss of APC function in cells?

Abnormal chromosome segregation. Signup and view all the answers

What is the estimated breast cancer diagnosis rate for women in certain Western countries?

1 in 8 women. Signup and view all the answers

How does the protein ARF contribute to the cellular processes in the context of cancer?

It inhibits MDM2 and stabilizes p53. Signup and view all the answers

What is one proposed diagnostic approach related to mutated APC DNA?

Establishing a test for early-stage colon cancer. Signup and view all the answers

What happens to normal cells after sustaining genetic damage compared to cancer cells?

They regularly undergo senescence. Signup and view all the answers

What can result from the inactivation of the TP53 gene within senescent cells?

Cells can resume progression toward malignancy. Signup and view all the answers

What is a significant consequence of BRCA1 and BRCA2 mutations?

They predispose women to breast and ovarian cancer. Signup and view all the answers

Which statement about the TP53 gene is accurate?

TP53 influences several tumor-related pathways. Signup and view all the answers

What types of modifications can influence the functionality of the p53 protein?

Phosphorylation, acetylation, methylation, and ubiquitination. Signup and view all the answers

What happens to cells with mutant BRCA proteins?

They accumulate chromosomal breaks and display an aneuploid karyotype. Signup and view all the answers

Which cellular event activates the p53 protein when DNA damage is not repaired?

Failure to repair DNA damage. Signup and view all the answers

What role do BRCA proteins primarily serve in relation to DNA damage?

They participate in DNA repair through homologous recombination. Signup and view all the answers

What challenge arises from the multifunctionality of the p53 protein?

Determining its various cellular roles is complex. Signup and view all the answers

Which oncogenes are often implicated in tumor formation?

KRAS and BRAF Signup and view all the answers

What function is associated with the BRCA2 oncogene?

DNA repair Signup and view all the answers

What role does the p21 gene play in cell biology?

Inhibits cell cycle progression Signup and view all the answers

Which of the following genes is NOT mentioned as involved in growth factors or their receptors?

p53 Signup and view all the answers

Which checkpoint activation is associated with controlling cell cycle progression?

p53 checkpoint Signup and view all the answers

What is the function of oncogenes that encode growth factors?

Promoting uncontrolled cell proliferation Signup and view all the answers

What role does apoptosis play in the body in relation to tumors?

It helps rid the body of potential tumor cells. Signup and view all the answers

Which pathway is primarily associated with cell survival instead of cell destruction?

PI3K/PKB pathway Signup and view all the answers

The SIS oncogene was discovered in relation to which virus?

Simian Sarcoma Virus Signup and view all the answers

What genetic alteration is commonly associated with Familial adenomatous polyposis coli (FAP)?

Deletion of a portion of chromosome 5 Signup and view all the answers

Which of the following oncogenes is primarily involved in apoptosis?

Bax Signup and view all the answers

What is the effect of the overexpression of PKB or PI3K on cells?

It shifts the balance towards cell survival. Signup and view all the answers

What is the potential implication of untreated premalignant polyps in patients with FAP?

They can progress to a fully malignant stage. Signup and view all the answers

What is necessary for a cell to live or die following a stimulus?

The balance between proapoptotic and antiapoptotic signals. Signup and view all the answers

What can mutations in tumor-suppressor genes lead to in terms of cancer development?

An increased likelihood of malignancies. Signup and view all the answers

What is the primary function of the phosphoinositide PIP3 in cell signaling?

It activates the kinase PKB (AKT). Signup and view all the answers

Study Notes

Inherited Mutations and Cancer

Mutations in genes are a primary cause of cancer.
Certain inherited syndromes are associated with a much higher chance of developing cancer.
While inherited mutations can contribute significantly to cancer risk, most cases are not caused by these mutations.
To assess the role of inheritance in cancer development, scientists study identical twins and assess the likelihood of them developing the same type of cancer.

Tumor Suppressor Genes

INK4a encodes tumor suppressor proteins that inhibit cell cycle progression and stabilize p53.
p53 plays a crucial role in cell cycle arrest, apoptosis, and senescence.
p53’s function depends on the type of post-translational modifications it undergoes.
TP53 gene inactivation allows senescent cells to become malignant.

Other Tumor Suppressor Genes

APC (Adenomatous Polyposis Coli) is a tumor suppressor gene involved in familial adenomatous polyposis (FAP).
Mutations in APC lead to the development of numerous premalignant polyps in the colon.
Loss of APC function contributes to abnormal chromosome segregation and aneuploidy.
BRCA1 and BRCA2 are tumor suppressor genes associated with inherited breast and ovarian cancer.
These genes are involved in DNA repair by homologous recombination.

Cell Survival and Apoptosis

PKB (AKT) is a kinase activated by PIP3, which is produced by PI3K.
The PI3K/PKB pathway promotes cell survival.
Mutations affecting this pathway can favor cell survival and contribute to cancer development.

Oncogenes

RAS and RAF oncogenes are often involved in tumor formation.
These genes regulate cell growth and division.

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Description

Explore the relationship between inherited mutations and cancer, as well as the role of tumor suppressor genes such as INK4a and p53. Understand how genetic factors contribute to cancer risk and the mechanisms by which these genes function to prevent malignancy. This quiz delves into significant scientific concepts and findings in oncology.