Lecture 21 - Cancer Flashcards
important epithelial cancer types
breast
colon
prostate
important examples of non epithelial cells
melanoma
all the blood ones
osteosarcoma
what is a carcinoma
tumours from epithelial cells
what are adenomas and adenocarcinomas
tumours arising from secretory epithelial cells
adenomas are benign
the other is malignant
why is cancer more prev in older people
is a multi step process
so it develops over decades
4what is the process that cancer follows
normal epithelium
mutation causes hyperplastic epithelium
early to intermediate to late adenoma
then turns into carcinoma
finally, invasion and metastasis
what is metastasis
spread of cancer to other places
4 of the hallmarks of cancer
- sustained proliferative signalling
- evading growth suppressors
- resisting cell death
- genome onstbaility and mutation
what genes need to be mutated to cause cancer
oncogenes
tumour suppressor genes
how do mutations disrupt tissue homeostasis
alters gene expression
dysfunctional protein networks
abnormal cell function
loss of tissue homeostasis
what is rous sarcoma virus
a retrovirus
causes cancer
- infected cells will hyperproliferate
how is RSV different from other retrovirus
RSV has an extra gene
v-src
what genes do retroviruses have that make it so they can inflitrate cells
gag
pol
env
what is v-src cellular coutnerpart
c-src
cancer causing gene
what is src
non receptor tyrosine kinase
activating it will stimulate cells to enter the cell cycle
what is ras
a viral oncogene and a cellular cancer causing gene if mutated
what is the ras mutation that causes signalling pathways to be constantly on
Ras G12V
only one allele needs to be mutated
causes inactivated of RASability to inactivate itself
what are types of oncogenic mutations
- mutation in coding sequence
- gene cmplification
- chromosome rearrangement
(either causing overexpression or fusion protein with a new function
what are the 2 types of retinoblastoma
- sporadic
no family history, only one eye, low risk of other tumours - familial
vice vers
what gene needs to be mutateed to cause retinoblastoma
Rb
and both copies
what happens when Rb mutated
can’t inhibit E2F as usual
and so E2F is active
and drives entry into S phase in absence of mitogens
what mutated gene causes neurofibromatosis
NF1 gene
NF1 is a tumour surpressor
and if lost, Ras is always active
what does wnt do
wnt is a mitogen
that when bound, it inhibits degraation of B catenin
so b catenin can go into nucleus and stim production of cyc D
what complex phosphorylates B catenin and subsequently tags it for degradation
GSK-3B, APC, B catenin comlpex
what 2 things can be mutated in wnt pathway that cause cancer
APC - a tumour supressor
B-catenin - an oncogene
what type of cancer is caused when wnt mutated
colon cancer
what is TGF-B signalling
acts as inhibitory ligand
so if its removed, then process not inhibited
