302 Cancer genetics

Question 1

What does degeneracy mean?

Answer 1

There are many different ways to make the same protein

Question 2

What is a single nucleotide polymorphism (SNP)

Answer 2

A single base change

Question 3

What does a RET gene mutation cause?

Answer 3

MEN2 syndrome
It increases your risk of cancer
- medullary thyroid cancer 90%
-Pheochromocytoma 50%
-Parathyroid adenoma 20-30%

There’s a variation of MEN2 that causes 100% risk of familial medullary thyroid cancer

Question 4

What is MEN2B?

Answer 4

A variation of a RET gene mutation
Increases risk of cancer
-Medullary thyroid cancer 90%
-Pheochromocytoma 40-50%

Associated abnormalities 40-50%:
mucosal neuromas, marfanoid, and toxic megacolon

This disease is mostly de novo and not inherited from parents

Question 5

Name some tumour suppressor genes

Answer 5

TP53 - Li Fraumeni syndrome
BRCA1- cause breast and ovarian cancer
MLH1

Question 6

What are the risks associated with a BRCA1 mutation?

Answer 6

80% breast cancer risk
60% ovarian cancer risk
Average onset is 50 years
80% is ER-ve cancer

No clear increase in prostatic, pancreatic, or male breast cancer

Question 7

What are the risks associated with a BRCA2 mutation?

Answer 7

80% breast cancer risk
30% ovarian cancer risk
25% prostatic cancer risk
Average onset is 55 years
80% ER+ve cancer
Small increase in pancreatic and male breast cancer risk

Question 8

What is Li Fraumeni syndrome?

Answer 8

Inherited condition causes by a TP53 mutation