GI Cancers

Question 1

what are the 2 main variants of esophageal carcinomas

Answer 1

• adenocarcinoma
• squamous cell carcinoma

Question 2

what are present at early stages of esophageal adenocarcinoma

Answer 2

mutation or overexpression of p53 are present at early stages of esophageal adenocarcinoma

Question 3

esophageal adenocarcinoma usually occurs in the ? and may invade the ?

Answer 3

distal third of the esophagus
adjacent gastric cardia

Question 4

in contrast to adenocarcinoma, half of squamous cell carcinomas occur in ?

Answer 4

the middle third of the esophagus

Question 5

what are the clinical features of esophageal carcinomas

Answer 5

dysphagia, odynophagia, obstruction

Question 6

gastric polyps are usually develop in association with ?

Answer 6

chronic gastritis

Question 7

what are the types of gastric adenocarcinoma

Answer 7

diffuse - diffuse infiltrative growth patterns
intestinal - composed of glandular structures

Question 8

what is the gene of interest of gastric adenocarcinoma

Answer 8

p53

Question 9

intestinal gastric adenocarcinoma are composed of

Answer 9

malignant cells forming neoplastic intestinal glands resembling those of colonic adenocarcinoma

Question 10

diffuse gastric adenocarcinoma are composed of

Answer 10

gastric-type mucous cells that generally do not form glands but rather permeate the mucosa and wall as scattered individual “signet-ring” cells or small clusters in an “infiltrative” growth pattern

Question 11

Most common cause of “pro-lymphomatous” inflammation in stomach is

Answer 11

chronic H. pylori infection

Question 12

gastric lymphoma originate

Answer 12

in GI tract at sites of preexisitng MALT such as the peyer’s patches of the small intestine

Question 13

what is the most important characteristic of colorectal adenocarcinoma that correlates with risk of malignancy

Answer 13

size

Question 14

what are the two genetic pathways for adenocarcinoma of the colon

Answer 14

• APC/beta-catenin pathway
• microsatellite instability pathway

Question 15

what is APC

Answer 15

a key negative regulator of beta catenin, component of the WNT signaling pathway

Question 16

with loss of APC function, what happens

Answer 16

beta-catnin accumulates and translocates to the nucleus

Question 17

what does beta catenin do

Answer 17

activates MYC and cyclin D1 which promotes proliferation

Question 18

Due to loss of mismatch repair genes, mutations accumulate in microsatellite repeats, a condition referred to as

Answer 18

microsatellite instability

Question 19

Hepatic adenomas have clinical significance for three reasons:

Answer 19

1. When they present as an intrahepatic mass they may be mistaken for the more ominous hepatocellular carcinomas
   
   2. Subcapsular adenomas have a tendency to rupture, particularly during pregnancy, causing life-threatening intraperitoneal hemorrhage
   3. Rarely, they may transform into carcinomas
      - Usually they are well-differentiated and are almost always benign

Question 20

what is the primary carcinomas of the liver

Answer 20

hepatocellular carcinoma

Question 21

what gene is the most frequently altered oncogene in pancreatic cancer

Answer 21

KRAS gene

Question 22

what is the main risk factor of pancreatic cancer

Answer 22

smoking

Question 23

KRAS gene does what

Answer 23

constitutively activation of Ras