Question

1. Cancers arise from a multistep process that involves the interplay of multiple changes, or mutations, in several different genes, in combination with environmental factors such as diet or lifestyle. Based on the relationship between genetic alterations and cancer development, please answer the following prompts:

1. If mutated, what gene would lead to the proliferation of cells that survive when they should not?

2. If mutated, what gene would lead to further mutations in other genes?

3. Identify and describe each stage of multistage carcinogenesis.

4. What are two examples of endogenous factors that can induce DNA damage? What are two examples of exogenous factors that can induce DNA damage?

Answer 1

a) gene p53 , if mutated will lead to proliferation of cells

B) genes of DNA polymerase enzyme if mutated will lead to further mutations in different genes due to malfunctioning of DNA polymerase enzyme and inducing more mutations per replication cycle.

C) stages-

1) tumor initiation- gradual mutations/ epigenetic changes leads to tummor suppressor genes inactivation and protooncognes to get converted to oncogenes. Thus, starting of tumor.

2)Promotion- Slowly , the no. Of tumor/mutated cells increase among proliferated cells and faster replicating more dangerous cells are naturally selected which promotes tumor further by self regulating there cell cycle by producing tumor promotion factors

3) malignant conversion- More mutations will lead to faster cell growth and conversion of such cells to malignant ones which lose their ground adhession and leak into other parts of body with help of blood vessel system.

4) tumor progression- these cells proliferate to other parts of the body And invade other cells and secreate proteases as a result they replace other cells and proliferate fast becoming more malignant and dangerous.

D) endogenous - oncogenes, Reactive oxygen species eg. H2O2

Exogenous - MIC gas , UV-C, UV-B rays