QuestionSBA
QuestionChoice
P53 is a tumour suppressor gene. Mutation in this gene can be seen in the development of sporadic cancers.

Mutations in P53 genes may cause cancer cells to grow and spread in the body and are linked to a genetic condition called Li- Fraumeni Syndrome which increases the risk of various cancers including sarcomas, breast cancer, leukaemias and adrenal cancer.
10005853
c
P53
QuestionChoice
BRCA genes are tumour suppressor genes and help repair damaged DNA that has had double-strand breaks.

When mutations occur, they increase the risk of developing cancers such as breast, ovarian, colorectal, pancreatic and prostate cancer.
10005851
a
BRCA1 and 2
QuestionChoice
This is a mismatch repair gene. These genes allow corrections that DNA polymerase has made. For example, insertion and deletion can be reversed to prevent frameshift mutations.

They specifically allow the detection of mistake in DNA. This allows the excision of the mistake and resynthesis of the DNA with DNA polymerase. There is a normal cell division rate but an increased mutation rate.

This is associated with Hereditary Non-polyposis Colorectal Carcinoma/ Lynch Syndrome. These patients can develop polyps which can rapidly convert to large, non-fibrous cancerous tumours in the colon.
10005852
b
MLH1
QuestionChoice
This is a tumour suppressor gene that regulates cell cycle progression. There is an inherited condition called Familial adenomatous polyposis (FAP) where a defective APC gene is inherited.

When defective, there is more susceptibility that the gene will develop more mutations that can lead to colorectal cancers as there is an increased rate of cell division.

Colonoscopy shows multiple benign tumours - polyp.
10005854
d
APC
QuestionChoice
These are also mismatch repair genes that lead to an increased mutation rate in Lynch syndrome.

The other genes associated are MLH1 and PMS1 and 2.
10005855
e
MSH2 and 6
Concept
Chapter
2693
4452
BRCA genes
Topic
226
Cancer Genes
13717
38 year old female presents to the GP with a painless breast lump. She felt it when she was in the shower about a year ago and has increased in size since then.

On examination, there is a 10mm by 20mm breast lump in the upper right quadrant of the left breast. It feels hard and nodular. There are no skin changes such as erythema and dipping

Her mother was diagnosed with breast cancer at 50 years of age and her grandfather on her mother's died from pancreatic cancer.

Which of these genes is likely to have contributed to the presentation in this family?
a