Molecular Neoplasia

Question 1

1. Define cancer and explain the importance of DNA mutations in the process of carcinogenesis.

Answer 1

initial event is the a nonleathal genetic alteration; mutations that effect cellular proliferation: DNA repair or programmed cell death resulting in clonal expansion of the cell with mutation; initial cell type is like a tissue stem cell or progenitor cell

Question 2

1. Describe the clonal evolution model for development of cancer.

Answer 2

clonal evolution describes a cellular mutation that gives a cell proliferative advantage over other cells, causing clonal expansion (development of tumor) ; while this expansion occurs, the cells may develop additional mutations that confer further proliferative advantage with additional mutations, a malignant neoplasm forms (process of becoming malignant is also called transformation, defined by autonomous dysregulated proliferation)

Question 3

1. How is the cancer stem cell model different from the clonal evolution model.

Answer 3

frontiers of science

Question 4

2. List the four principal targets of genetic damage that lead to cancer.

Answer 4

inactive DNA repair genes
activated oncogenes
inactivated tumor suppressor genes
activate cell survival genes

Question 5

3. Define replicative error, mutational activation and transcriptional activation of oncogenes.

Answer 5

replicative error: cell/injury/repair elicited chronic inflammation and chronic infection is associated with cancer (replicating cells are sensitive to mutagenesis, DNA repair not efficient in the S phase)
replicative error can lead to activation of genes that promote cancer formation (oncogenes) and turn off cell cycle moderation (tumor suppressants)