Gastrointestinal Cancers

Question 1

2 types of oesophageal cancer

Answer 1

• Squamous cell cancer (SCC)
• Adenocarcinoma (ADC)

Question 2

Stages of oesophageal adenocarcinoma development

Answer 2

Normal squamous epithelium –> Barrett’s metaplasia –> Dysplasia –> Adenocarcinoma

Question 3

Risk factors for oesophageal adenocarcinoma

Answer 3

• Barrett’s metaplasia
• Gender (men > women)
• Age
• Reflux
• LOS relaxing drugs
• Obesity (as increased intra-abdo pressure

Question 4

Protective factors against oesophageal adenocarcinoma

Answer 4

• H-pylori
• Fruit + veg
• Anti-oxidants

Question 5

Most important risk factor of gastric cancer

Answer 5

Helicobacter pylori infection

Question 6

What does h-pylori infection of the antrum cause?

Answer 6

• Hypergastrinaemia
• Duodenal ulcers

Question 7

What does h-pylori infection of the corpus cause?

Answer 7

• Reduced acid secretion
• Hypochlorhydria

Question 8

Treatment of h-pylori infection

Answer 8

• Triple therapy:
  > Amoxicillin
  > Clarithromycin
  > Proton pump inhibitor

Question 9

H-pylori equation converting urea to bicarbonate

Answer 9

C=O(NH2)2 + H+ + 2H2O –> HCO3- + 2NH4+

Question 10

How does h-pylori infection of the corpus cause hypochlorhydria?

Answer 10

IL-1b down regulates gastrin

Question 11

What is hereditary diffuse gastric cancer (HDGC) caused by?

Answer 11

Germline mutations in the CDH1 gene

Question 12

What is E-cadherin?

Answer 12

Main transmembrane protein in adherens junction (cement in a brick wall)

Question 13

Why is an E-cadherin deficient cancer worse?

Answer 13

Cells are not connected to metastasise to more locations

Question 14

What causes E-cadherin repression?

Answer 14

• Epigenetic events
• Promoter hypermethylation
• EMT regulators (snail/slug)

Question 15

Risk factors of colorectal cancer

Answer 15

• Increased red/processes meat
• Decreased fish
• Decreased fibre
• Obesity
• Decreased physical activity
• Alcohol
• Decreased aspirin/other NSAIDs

Question 16

Types of colorectal cancer

Answer 16

• Sporadic
• Familial (FAP + HNPCC)

Question 17

What is familial adenomatous polyposis coli (FAP) and what is it caused by?

Answer 17

• Multiple benign adenomatous polyps at an early age
• Mutated APC gene on chromosome 5q21

Question 18

How is familial adenomatous polyposis coli treated?

Answer 18

Prophylactic surgery

Question 19

Types of polyps that can arise from GI mucosa

Answer 19

• Adenomatous (become cancer)
• Serrated (less risk)
• Non-neoplastic (less risk)

Question 20

What does the National Bowel Cancer Screening Program aim to identify?

Answer 20

Asymptomatic individuals with potentially curable disease

Question 21

What test does the National Bowel Cancer Screening Program use, and what are the results of this?

Answer 21

• Faecal occult blood test
• 1.9% have +ve test and get colonoscopy

Question 22

What is drug repurposing?

Answer 22

Using drugs intended for 1 purpose for a different purpose (usually old so cheaper)

Question 23

How can metformin be used to treat colorectal cancer?

Answer 23

Suppressor of growth of the cancer