molecular biology of cancer

Question 1

What is the primary cause of cancer?

Answer 1

Cancer is caused by changes to the nucleic acid DNA, including mutations, deletions, translocations, and epigenetic changes.

Question 2

What does molecular biology study in relation to cancer?

Answer 2

Molecular biology studies the composition, structure, and interactions of cellular molecules such as nucleic acids and proteins, which play a role in cancer development.

Question 3

How do the changes in DNA contribute to cancer?

Answer 3

The changes in DNA result in abnormal (neoplastic) cell growth, leading to the formation of tumors.

Question 4

What is the multistep nature of carcinogenesis?

Answer 4

Carcinogenesis, the process of cancer development, typically occurs through multiple steps involving the accumulation of genetic and epigenetic changes in cells.

Question 5

How can oncogenic transformation be assessed in primary cultures?

Answer 5

Primary cultures can be used to assay oncogenic transformation. For example, cells from a hamster embryo are enzymatically dissociated, seeded as single cells, and then treated with radiation or chemicals. The resulting colonies are scored after 8-10 days after staining.

Question 6

What are some lifestyle factors that can increase the risk of cancer?

Answer 6

Smoking, a diet high in red meat, saturated fat, and salt, and lack of exercise can increase the risk of cancer.

Question 7

Which virus is associated with an increased risk of cancer?

Answer 7

Human Papillomavirus (HPV) is a virus that is associated with an increased risk of certain types of cancer.

Question 8

What are some environmental factors that can contribute to cancer?

Answer 8

Environmental factors such as exposure to particulate matter (soot, traffic pollution) can increase the risk of cancer.

Question 9

How can hormones affect cancer risk?

Answer 9

High estrogen levels and the use of hormone-related medications like Tamoxifen can impact cancer risk.

Question 10

Are inherited genes a factor in cancer development?

Answer 10

Yes, inherited genes like BRCA1 and BRCA2 are associated with an increased risk of developing certain types of cancer.

Question 11

How can ionizing radiation and sunlight contribute to cancer development?

Answer 11

Ionizing radiation and excessive sunlight exposure can cause DNA damage, which can increase the risk of cancer.

Question 12

What are some acquired gene mutations associated with cancer?

Answer 12

Overexpression of genes like EGFR and HER2 can contribute to the development of cancer.

Question 13

: Can natural cell processes contribute to cancer development?

Answer 13

Yes, natural cell processes can sometimes go awry and lead to the development of cancer.

Question 14

What is the significance of the Philadelphia chromosome in cancer?

Answer 14

The Philadelphia chromosome, a translocation between chromosome 9 and 22, is observed in most patients with chronic myelogenous leukemia (CML).

Question 15

What are the two major classifications of mutated genes in cancer?

Answer 15

The two major classifications are oncogenes and tumor suppressor genes.

Question 16

How do oncogenes differ from tumor suppressor genes in terms of mutation effects?

Answer 16

Mutations in oncogenes cause a gain of function, resulting in the production of higher quantities of the protein product or an altered product with increased activity, acting in a dominant manner. Mutations in tumor suppressor genes cause a loss of function, mainly in a recessive manner, requiring both alleles to be mutated. However, haploinsufficiency can occur in some cases.

Question 17

What are the characteristics of oncogenes?

Answer 17

Oncogenes are genes that, when mutated, can promote abnormal and unregulated cell growth, leading to the development of tumors. They act in a dominant manner.

Question 18

What are the characteristics of tumor suppressor genes?

Answer 18

Tumor suppressor genes are genes that normally inhibit cell growth and division. Mutations in tumor suppressor genes can result in the loss of their inhibitory function, leading to abnormal cell growth. Tumor suppressor genes typically act in a recessive manner, requiring mutations in both alleles.

Question 19

What is the concept of haploinsufficiency in tumor suppressor genes?

Answer 19

Haploinsufficiency occurs when a single functional copy of a tumor suppressor gene is insufficient to maintain normal growth regulation, leading to abnormal cell growth.

Question 20

What is the difference between proto-oncogenes and oncogenes?

Answer 20

Proto-oncogenes are normal genes that are involved in regulating cell growth. When proto-oncogenes undergo specific mutations, they can become oncogenes, which promote uncontrolled cell growth and can lead to cancer development.

Question 21

How do proto-oncogenes get activated to become oncogenes?

Answer 21

Proto-oncogenes can be activated through mutations that result in increased or abnormal protein production or altered protein activity. This activation can disrupt normal growth regulation and contribute to cancer development.

Question 22

What are epigenetic changes?

Answer 22

Epigenetic changes refer to alterations in gene expression that are encoded by modifications of the genome and its chromatin components. These changes do not involve changes in the DNA sequence but can affect the phenotype without altering the genotype.

Question 23

What are some examples of epigenetic mechanisms in cancer?

Answer 23

Some examples of epigenetic mechanisms in cancer include histone acetylation, histone methylation, and DNA methylation.

Question 24

How are DNA methylation alterations involved in cancer?

Answer 24

DNA methylation alterations are often early events in tumorigenesis. They play an important role in the regulation of gene expression in cancer cells. Specific methylation profiles have been observed with mutated genes involved in lung cancer, such as EGFR, KRAS, and TP53.

Question 25

What are the hallmarks of cancer?

Answer 25

The hallmarks of cancer refer to the fundamental characteristics that define cancer cells. These include: sustained proliferative signaling, evasion of growth suppressors, resistance to cell death, enabling replicative immortality, induction of angiogenesis, activation of invasion and metastasis, reprogramming of energy metabolism, and evading immune destruction.

Question 26

Why is angiogenesis important in tumor progression?

Answer 26

Angiogenesis, the formation of new blood vessels from pre-existing ones, plays a crucial role in tumor progression. Vascular endothelial growth factor (VEGF) is a key growth factor in angiogenesis, secreted by hypoxic cancer cells. Activation of VEGF receptor 2 (VEGFR2) leads to the growth of new blood vessels, providing nutrients and oxygen to the tumor, promoting its growth and metastasis.