32 - CANCER GENETICS 2 Flashcards
what are the two types of retinoblastoma
rare cancer of the eye in childhood
can be unilateral or bilateral
what is the two hit hypothesis that knudson developed for retinoblastoma
retinoblastoma results from two separate genetic defects (mutations), two hits
how does sporadic retinoblastoma happen (unilateral)
how does inherited retinoblastoma happen (bilateral)
how do oncogenes and tumor suppressor genes mutations express?
oncogenes: mutant alleles tend to be dominant
tumor suppressor genes: tend to be recessive acting
the chance of acquiring the second mutation in a somatic cell is high
in theory, a single cell acquiring the second mutation is enough to cause cancer
not all carriers will develop cancer
what are the phases of the cell cycle and the checkpoints?
how does the RB protein work?
what are the things that affect/are affected by p53
what are the domains of p53 and where do the mutations happen
TAD: transcription activation domain
DBD: DNA binding domain
OD: oligomerization domain
most mutations (if not all) happen in the DBD, which makes it unable to bind DNA
but able to form the tetramer
p53 is mutated in more than 50% of all human tumors
what is p53 and how do the mutant alleles function
how does HPV act
viral oncoproteins (E7 and E6) from DNA virus bind and inactivate Rb and p53
how does clonal evolution of cancer cells happen
how does colon cancer development happen
defined genetic changes are associated with specific stages of colon cancer development
loss of normal tumor suppressor gene APC
APC=familial adenomatous polyposis
1. a polyp (small growth) forms on the colon wall
2. a benign, pre cancerous tumor grows
activation of the oncogene ras
3. an adenoma (benign tumor) grows
loss of tumor suppressor gene p53
4. a carcinoma (malignant tumor) develops
other changes: loss of anti metastasis gene
5. the cancer metastasizes and spread to other tissues through the bloodstream
