Question

A man who had colon cancer has an aunt who also had the same type of colon cancer. The man's son has just been diagnosed with the same type of colon cancer and doctors perform genome sequencing of his cancer cells and normal cells. If this cancer is associated with an inherited mutation, select the expected results of genome sequencing.
Check All That Apply

A. His normal cells are heterozygous for a loss-of-function allele of a tumor-suppressor gene.

B. The cancer cells have two loss-of-function alleles of a tumor-suppressor gene.

C. The cancer cells have two loss-of-function alleles of an oncogene.

D. His normal cells are heterozygous for a gain-of-function allele of an oncogene.

Answer 1

If this cancer is associated with an inherited mutation, the expected results of genome sequencing is his normal cells are heterozygous for a loss-of-function allele of a tumor-suppressor gene.

Option A

Explanation:

Oncogenes are defined as the genes that are responsible for production of different proteins that are responsible for the formation of cancers and tumours in the body of a human. Tumour suppressor genes are the genes that are responsible for the production of certain proteins that are responsible to suppress the expression of Oncogenes.

In this person, he had a genetic defect in one of the alleles of a Tumour suppressor gene. This leads in the inability of suppression of the Oncogenes of that person, which produce the colon cancer. As this defect is congenital and hereditary, persons sharing his genes are all having defected allele of TSG. Thus this heredity suffers a colon cancer history running in their family.