Genetics Flashcards
What are some of the causes of hereditary susceptibility to colorectal cancer ?
Sporadic (65%)
Rare CRC Syndromes
Lynch syndrome
Familial
What are the 2 types of mutations which occur and can predispose people to cancer ?
Germaline mutations
Somatic mutations
Which type of mutations cause cancer family syndromes ?
Germaline Mutations
Which type of gene mutations are nonheritable ?
Somatic mutations
Where in the cell cycle do oncogenes contribute ?
After G1 (Cell growth)
Where in the cell cycle do tumor suppressor genes contribute ?
Between G0 and Synthesis (S)
Where in the cell cycle does DNA repair genes ?
Between synthesis and G2
How many mutations are need for cancer development ?
1 Mutation is sufficient for role in cancer development ?
In cancer what takes a normal epithelium to a hyper-proliferative epithelium ?
Loss of APC
In cancer what takes an early adenoma to an intermediate adenoma ?
Activation of K-ras
In cancer what takes an intermediate adenoma to a late adenoma ?
Loss of 18q
In cancer what takes a late adenoma to a carcinoma ?
Loss of TP53
What is the main mechanism for familial cancer ?
Faulty DNA mismatch repair
What is Lynch syndrome/Hereditary Non-Polyposis Colon Cancer ?
Mutation in mismatch repair genes
Excess of colorectal, endometrial, urinary tract, ovarian and gastric cancers.
What are the clinical features of Hereditary Non-Polyposis Colon Cancer ?
Early but variable age
Tumour site in proximal colon predominates
What areas in the body are cancer most likely in Lynch syndrome ?
Colon
Endometrial