Colorectal Cancer

Question 1

Familial adenomatous polyposis (FAP) is an autosomal ____ disorder, where there are mutations in APC gene and KRAS. 100% of patients with this disorder will develop colorectal cancer by the age of 40 if it remains untreated.
A. Dominant
B. Recessive
C. Heterogenous

Answer 1

A. Dominant

Question 2

True or False: Hereditary nonpolyposis colorectal cancer (HNPCC, Lynch Syndrome) is a type of autosomal dominant disorder caused by gremlin mutations in DNA mismatch repair (MMR) genes, and results in colorectal cancer.

Answer 2

True

Question 3

Micro satellite instability (MSI) analyzes the DNA length because tumor cells will insert and delete DNA sequences inappropriately, leading to defective sequences and frameshift mutations. Which of the following levels of MSI is associated with a good prognosis, but is unlikely to benefit from fluorouracil monotherapy?
A. Microsatellite stable (MSS)
B. MSI-low
C. MSI-high

Answer 3

C. MSI-high

Question 4

High dietary fiber and chronic NSAID use can be used in prevention. Because 90% of CRC patients have increased COX2 expression, this COX2 inhibitor is indicated for patients with the hereditary syndrome FAP as adjunct to standard treatment.

Answer 4

Celecoxib 400 mg PO BID

Question 5

When it comes to the sidedness of colorectal cancer, which has the worst prognosis?
A. Ascending (right sided)
B. Decending (Left sided)
C. Sigmoidal/rectal

Answer 5

A. Ascending (right sided colon cancer)

Question 6

True or False: The right side of the colon is only identifiable with a colonoscopy.

Answer 6

True

Question 7

90-95% of colorectal cancers have this pathology.

Answer 7

Adenocarcinoma

Question 8

Which mutations should be tested for if a patient has colorectal cancer?

Answer 8

KRAS, NRAS, BRAF

Question 9

True or False: EGFR inhibitors do not work on colorectal tumors in the descending colon.

Answer 9

FALSE! They work on the descending colon, but don’t worry on the ascending colon regardless of tumor mutations.