Genetic Predisposition For Cancer

Question 1

What are the differences between somatic and germline mutations?

Answer 1

Somatic mutations are those which occur in nongermline tissues and are non inheritable.
Germline mutations are present occur in eggs or sperm and are heritable.

Question 2

What are three genes associated with cancer and what do they do?

Answer 2

Oncogenes
Tumour suppressor genes
DNA damage response genes
They accelerate cell division.

Question 3

What are proto-oncogenes?

Answer 3

Normal version of the gene that codes for proteins to regulate cell growth and differentiation.
When it mutates it becomes an oncogene. One mutation is enough to cause cancer.

Question 4

What is the Knudson two hit hypothesis?

Answer 4

It happens in tumour suppressor gene mutations and means that two mutations of the gene are needed to cause cancer.

Question 5

What is MSI and what does it arise from?

Answer 5

Microsatellite Instability is the addition of nucleotide repeats and occurs due to mismatch repair.

Question 6

What does dysplastic mean?

Answer 6

It means a benign growth that could lead to malignancy due to abnormally of cells and their appearance and maturation.

Question 7

What is the dominant tumour suppressor gene that causes breast cancer in women, and women and males?

Answer 7

BRCA1

BRCA2

Question 8

What is retinoblastoma?

Answer 8

An inheritable or non inheritable eye tumour commonly found in children.

Question 9

What is the cause of colorectal cancer?

Answer 9

Failure of MMR genes

Question 10

What are four types of hereditary colorectal cancer syndromes?

Answer 10

Non polyposis CRC have few adenomas such as HNPCC.
Polyposis CRC have multiple adenomas such as
FAP-familial adenomatous polyposis
AFAP-attenuated FAP
MAP-MYH associated polyposis