Medical Genetics - V. M. Zaporozhan 2005

Fundamentals of Oncogenetics
Review Questions for Chapter 8

1. Tumors as a multifactorial pathology and diseases caused by somatic Cell Mutations.

2. Differences between tumor Cells and normal tissue cells.

3. Regulation of the Mitotic Cycle. Checkpoints.

4. General characteristics of genes responsible for tumor development.

5. Viral Oncogenes.

6. Mechanisms of action of Proto-oncogenes. Pathways of conversion of proto-oncogenes into oncogenes.

7. Tumor suppressor genes. Examples of hereditary tumors and Cancer-related genetic syndromes.

8. Mechanisms of homozygotization in hereditary tumors. Knudson's hypothesis.

9. The Role of Mutator Genes.

10. Carcinogenic Factors.

11. Application of Molecular Genetic Methods in oncology.

Self-assessment and study questions

Select one answer.

1. The Development of a malignant tumor is associated with specific cellular genes that normally activate cell mitosis. Activation or modification of their Functions significantly accelerates cell proliferation. Name these genes:

A. Proto-oncogenes

B. Tumor Suppressors

C. Genes involved in DNA Repair

2. The targets of proto-oncogene action are:

A. Genes promoting apoptosis

B. Growth factors and growth factor receptors

C. Receptors for antimitogenic factors

D. Antimitogenic Gene activator

E. Inhibitors of mitosis-stimulating factors

3. Most hereditary forms of tumors are caused by the inheritance of mutant:

А. Oncogenes

Table 8.4. Tumor-susceptibility genes

B. Tumor suppressor genes

C. Mutator genes

4. A patient is diagnosed with Li-Fraumeni syndrome (multiple primary tumors). Mutation of which gene is responsible for this syndrome?

A. p53

B. RAS

C. SRC

D. c-MYC

E. BRCA (1, 2)

5. A mutation in the p53 gene is observed in 50% of all sporadic tumors. What normal cellular processes does it control?

A. Returns differentiated cells from the G₀ phase to the mitotic cycle

B. Encodes growth factor receptors

C. An adapter protein that transmits signals from growth factor receptors to The Nucleus

D. Triggers the apoptotic program in response to cellular genetic damage

E. Encodes DNA repair Enzymes

6. A 10-year-old boy presents with hyperpigmented exposed Skin areas, freckles, telangiectasias, and keratosis, along with a malignant lip tumor. These symptoms are associated with impaired repair of UV-damaged DNA. What is the Diagnosis?

A. Familial melanoma

B. Lynch syndrome

C. Retinoblastoma

D. Xeroderma pigmentosum

E. Von Hippel-Lindau syndrome

7. One form of hereditary human colorectal cancer (familial polyposis) is caused by the inactivation of the APC gene, which encodes ubiquitin ligase, an enzyme that accelerates the degradation of mitosis stimulators

cyclin B and β-catenin. To which group of genes does this mutant gene belong?

A. Oncogenes

B. Proto-oncogenes

C. Tumor suppressor genes

D. Mutator genes

8. A 22-year-old healthy woman is examined in a Molecular Genetics laboratory; her mother and grandmother both had breast cancer. The woman is found to carry the mutant BRCA1 gene. The probability of developing breast cancer in this woman is:

A. 0 %

B. 5 %

C. 25 %

D. 50 %

E. 85 %

9. A group of chemical plant workers in contact with aromatic amines was examined to determine The activity of the enzyme N-acetyltransferase. A subgroup of slow acetylators was identified. Which of the following pathological conditions are these workers at risk of developing?

A. Pulmonary emphysema

B. Breast cancer

C. Urinary Bladder cancer

D. Multiple endocrine neoplasia

E. Retinoblastoma

10. In 1971, Knudson proposed the two-hit hypothesis of homozygotization. This hypothesis explains:

A. The MECHANISM OF ACTION of oncogenes

B. The Mechanism of conversion of proto-oncogenes into oncogenes

C. Tumor development upon inheritance of a mutant tumor suppressor gene

D. DNA repair

E. The mechanism of action of proto-oncogenes