BRCA1 and BRCA2 are human genes that code for tumour suppressor proteins. Mutations in BRCA1 and BRCA2 can cause cancer (lines 1–2). Explain how.

Genetic testing, using DNA from saliva, can screen for all known harmful mutations in both genes (lines 5–6). Describe how this DNA could be screened for all known harmful mutations in both genes.

Effective treatment of ER-positive breast cancers often involves the use of drugs which have a similar structure to oestrogen (lines 9–10).

Suggest and explain how these drugs are an effective treatment of ER-positive breast cancers.

Blood tests can be used to test for cancers (line 11). However, the results of blood tests may not be conclusive when testing for prostate cancer. Explain why.

Treatment with drugs might be able to reverse the epigenetic changes that cause cancers (lines 16–17). Suggest and explain how.