Cancer Biology and Genetics

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Questions and Answers

What is a characteristic of malignant cells?

Decreased proliferation

Normal cellular differentiation and proliferation

Increased cellular differentiation

Loss of cellular differentiation and increased proliferation (correct)

What type of mutations can lead to cancer?

Point mutations and chromosome rearrangement (correct)

Neither point mutations nor chromosome rearrangement

Chromosome rearrangement only

Point mutations only

What is the function of proto-oncogenes?

To suppress the cell cycle

To repair DNA damage

To encode proteins that stimulate the cell cycle (correct)

To encode proteins that inhibit apoptosis

What is the effect of oncogenes on the cell cycle?

Pathological activation of the encoded protein, leading to cell cycle activation Signup and view all the answers

What is the function of tumor suppressor genes?

To suppress the cell cycle Signup and view all the answers

What is the function of p53?

To induce apoptosis Signup and view all the answers

What is the effect of mutated proto-oncogenes on the cell cycle?

Pathological activation of the encoded protein, leading to cell cycle activation Signup and view all the answers

What is the effect of mutated tumor suppressor genes on the cell cycle?

Pathological activation of the encoded protein, leading to cell cycle activation Signup and view all the answers

What effect does the mutation of telomerase in somatic cells have on cancer development?

It leads to the immortalization of cells. Signup and view all the answers

How does the cell cycle respond to DNA damage under normal conditions?

It temporarily halts until the damage is repaired. Signup and view all the answers

Which type of cancer is specifically associated with mutations in DNA repair genes such as BRCA?

Breast cancer Signup and view all the answers

What is a characteristic of most cancer treatments?

They are mostly non-specific and target all rapidly dividing cells. Signup and view all the answers

What is the goal of targeted cancer treatments?

To prevent new blood vessel growth. Signup and view all the answers

Which drug specifically targets the HER2 receptor in breast cancer?

Herceptin Signup and view all the answers

What role do proto-oncogenes play in cancer?

They promote cell proliferation. Signup and view all the answers

What is the significance of serum testing for cancer antigens such as PSA?

It helps in early detection and monitoring of certain cancers. Signup and view all the answers

What role does p53 play at the G1/S checkpoint?

It induces p21 to inhibit CDK2. Signup and view all the answers

Which CDK partner is crucial for regulating the G2 checkpoint?

Cyclin-B Signup and view all the answers

Which of the following is a consequence of p53 mutation in cancer?

Loss of p21 expression. Signup and view all the answers

During what phase does cyclin-A/CDK-2 phosphorylate proteins involved in the DNA replication complex?

S phase Signup and view all the answers

What initiates the destruction of cyclin-B/CDK-1 at the M checkpoint?

Ubiquination by anaphase-promoting complex. Signup and view all the answers

What is the role of APC/C in the cell cycle?

To facilitate the degradation of cyclins. Signup and view all the answers

Which protein complex is necessary for the attachment of chromosomes to the spindle apparatus during the M checkpoint?

APC/C Signup and view all the answers

Which of the following represents a characteristic of cancer related to cell cycle regulation?

Mutations in cell-cycle checkpoint genes. Signup and view all the answers

Study Notes

Cancer Characteristics

Point mutations, chromosome rearrangement, loss, or gain can lead to cancer
Mutant cell clones can expand and form tumors
Cancer cells often have decreased cellular differentiation and increased proliferation
Cancer cells can be pathologically invasive

Cancer Causation

As cells age, mutations can accumulate and lead to malignancy

Gene Groups Mutated in Cancer

Proto-oncogenes (e.g. EGFR, Src, Ras, Myc) can become oncogenes when mutated, leading to cell-cycle activation and tumor formation
Tumor suppressor genes (e.g. p21, p16, p53) normally suppress the cell cycle
When mutated, tumor suppressor genes can lose their function and allow cell-cycle activation
Genes that repair DNA (e.g. BRCA) are important for preventing cancer

Cell Cycle Regulation

Cyclin-E/CDK2 phosphorylates target proteins and initiates S-phase
The restriction checkpoint is guarded by p53 and can be breached by mutations in p53
Cyclin-A/CDK-2 regulates transit throughout S-phase
Cyclin B/CDK-1 regulates the G2 checkpoint and is required for mitosis
Cyclin B/CDK-1 triggers its own destruction and pushes cells into anaphase

Cancer Prevention and Treatment

Cancer prevention involves detecting and repairing DNA mutations
Cancer treatments often target specific molecules or processes (e.g. Rituxan targets CD20, Herceptin targets HER2)
Goals of cancer treatment include targeting metastasis, angiogenesis, and specific molecules

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Description

This quiz covers the characteristics and causation of cancer, including point mutations, chromosomal rearrangement, and gene mutations. It also explores the 5 gene groups that are mutated in cancer.