Read the following passage.
TP53TP53TP53 and APCAPCAPC are human genes that code for tumour suppressor proteins. Mutations in TP53TP53TP53 and APCAPCAPC can cause colorectal cancer. Specific inherited and somatic mutations in these genes increase the risk of colorectal cancers and have been associated with increased risks of several other types of cancer. Genetic testing, using DNA extracted from a blood sample, can screen for all known harmful mutations in both genes.
Androgen-receptor (AR)-positive prostate cancers have receptors for the hormone testosterone. These cancers develop and progress as a result of increased testosterone concentrations in the blood. Effective treatment of AR-positive prostate cancers often involves the use of drugs which have a similar molecular structure to testosterone.
Blood tests can be used to test for specific cancers. Individuals with colorectal cancer often have a high concentration of carcinoembryonic antigen (CEA) in their blood. However, heavy smoking, inflammatory bowel disease (IBD), and liver cirrhosis can also increase concentrations of CEA.
Recent development of epigenetic therapies has indicated that several cancers result from epigenetic abnormalities, such as altered promoter methylation. Treatment with epidrugs could be able to reverse the epigenetic changes that cause colorectal cancers.
Use the information in the passage and your own knowledge to answer the following questions.
TP53TP53TP53 and APCAPCAPC are human genes that code for tumour suppressor proteins. Mutations in TP53TP53TP53 and APCAPCAPC can cause cancer. Explain how.
Genetic testing, using DNA extracted from a blood sample, can screen for all known harmful mutations in both genes. Describe how this DNA could be screened for all known harmful mutations in both genes.
Effective treatment of AR-positive prostate cancers often involves the use of drugs which have a similar molecular structure to testosterone. Suggest and explain how these drugs are an effective treatment of AR-positive prostate cancers.
Blood tests can be used to test for cancers. However, the results of blood tests may not be conclusive when testing for colorectal cancer using CEA. Explain why.
Treatment with epidrugs could be able to reverse the epigenetic changes that cause colorectal cancers. Suggest and explain how.
