Tumors of Small and Large Bowel Flashcards
GIST: mutation in what gene?
c-Kit
carcinoid tumors of GI tract: symptoms (3)
diarrhea, wheezing, elevated serotonin (5-HT) 5-HIAA
dx: growths of normal colonic tissue with distorted architecture
hamartoma
juvenile polyposis syndrome: what is it and for what are these patients at increased risk?
multiple hamartomatous polyps in stomach, small intestine or colon; colon cancer
Peutz-Jeghers syndrome: what is it and for what are these patients at increased risk?
multiple hamartomatous polyps in GI tract associated with hyperpigmentation of mouth, lips, hands; increased risk of cancer in pancreas, lung, and female cancers
what type of polyp is premalignant?
sessile serrated
pathogenesis of sessile serrated polyps (3)
BRAF mutations, hypermethylation, microsatellite instability
tubular vs. villous adenoma: size, shape, location
size: tubular = small; villous = large
shape: tubular = pedunculated; villous = sessile
location: tubular = colon; villous = rectosigmoid colon
dietary risk factors for colorectal carcinoma
meat, low fiber
right or left sided colon cancer: iron deficiency anemia
right-sided
right or left sided colon cancer: abdominal pain
left-sided
right or left sided colon cancer: obstructive
left-sided
________ in an older male signifies colon cancer until proven otherwise
iron deficiency anemia
adenoma-carcinoma sequence in colorectal carcinoma
AK-53:
- loss of APC
- K-RAS mutation
- loss of p53
what does dysfunction of APC cause in the adenoma-carcinoma sequence?
decreased cell adhesion and increased cellular proliferation
FAP: gene involved, inheritance, increased risk of what, treatment
APC (two-hit hypothesis); autosomal dominant; colon adenocarcinoma; prophylactic colectomy
dx: FAP + osseous and soft tissue tumors
Gardner syndrome
dx: FAP + malignant CNS tumor
Turcot syndrome
Garner syndrome
FAP + osseous and soft tissue tumors
Turcot syndrome
FAP + malignant CNS tumor
MYH protein
base excision repair; repairs oxidation-induced DNA damage by removing A mis-paired with G
Lynch syndrome: pathogenesis, increased risk of what
defect in DNA mismatch repair (MMR) genes with subsequent microsatellite instability; colorectal, endometrial, ovarian, skin cancer
microsatellite instability means better or worse clinical outcome and better or response to adjuvant chemo?
MSI: better clinical outcome, worse response to adjuvant chemo
GIST: most specific marker
DOG1
genes involved in juvenile polyposis syndrome (2)
SMAD4, BMPR1A
gene involved in Peutz-Jeghers syndrome
STK11
distribution of colorectal cancer
RAD: rectosigmoid > ascending colon > descending colon
risk factors for colorectal carcinoma (2)
adenomatous and serrated polyps
apple-core lesion on x-ray
colorectal carcinoma
depth of invasion for TIS, T1, T2, and T3 colorectal cancer
TIS: mucosa
T1: submucosa
T2: muscularis externa
T3: serosa
define Stage I-IV colorectal cancers
Stage I: T1 or T2, N0, M0
Stage II: T3 or T4, N0, M0
Stage III: any T, positive nodes, M0
Stage IV: any T, any N, M1 (distant metastases)
2 monoclonal antibodies used for metastatic colorectal cancer
bevacizumab, cetuximab
monoclonal antibody against EGFR used in colorectal cancer
cetuximab
contraindications for cetuximab treatment
KRAS or BRAF mutations
MAP: gene involved
MYH
4 genes involved in mismatch repair implicated in Lynch syndrome and their respective functions
MSH2/MSH6: identifies mismatch
MLH1/PMS2: fixes mismatch
