Question

• Start your discussion post with a summary paragraph on the major groups of genes that when mutated can cause cancer, and include the types of mutations that can change their protein structure.
• Your next paragraph will focus on your gene of choice. You should find one to two reliable sources that discuss that gene. Focus on the group of cancer-causing genes that this gene belongs to, its normal function, and why the mutation can lead to the cell cycle becoming out of control.
• Is your mutated gene inherited, or does it become mutated throughout a person’s lifetime?
• If you could develop a drug that treats cancer caused by your mutated gene, how would the drug work? Would the drug damage non-cancerous cells as well? Explain

Answer 1

Answer: Cancer is the uncontrolled growth and division of cells. The major groups of genes that when mutated can cause cancer is the tumour suppressor genes and genes that cause apoptosis. Tumour suppressor genes inhibit the cell division thereby regulating the uncontrolled cell growth. A single point mutation causing frameshift cause make the protein product dysfunctional. Many genes cause apoptosis or programmed cell death. Mutations in a single nucleotide or sequence of nucleotides (due to breakage) can inhibit the usual cell death leading to excessive cell growth causing cancer. Similarly, the gain-of-function mutation of proto-oncogenes can cause overexpression (oncogenes) and cause cancer.

One such tumour suppressor gene that controls uncontrolled cell division is that encodes a cell cycle checkpoint protein, retinoblastoma (RB) protein. If there is DNA damage (mutation), then these proteins do not allow the cells to enter into the other stages of cell cycle and divide. RB protein prevents the damaged from passing the G1/S checkpoint. Mutation in the RB gene causes major cancers.

Mutated RB gene is inheritable and if both the alleles are mutated it causes cancers in humans.

Synthetic production of wild-type RB gene can be developed and used in gene therapy. This gene will be integrated into the genome of the cell and will start producing functional RB proteins. This will not damage the non-cancerous cells, because this protein is natural and will only inhibit cell division of damaged cells (cells not prepared for division or the DNA of the cell has been damaged).