Gastrointestinal Cancers Flashcards
2 types of oesophageal cancer
- Squamous cell cancer (SCC)
- Adenocarcinoma (ADC)
Stages of oesophageal adenocarcinoma development
Normal squamous epithelium –> Barrett’s metaplasia –> Dysplasia –> Adenocarcinoma
Risk factors for oesophageal adenocarcinoma
- Barrett’s metaplasia
- Gender (men > women)
- Age
- Reflux
- LOS relaxing drugs
- Obesity (as increased intra-abdo pressure
Protective factors against oesophageal adenocarcinoma
- H-pylori
- Fruit + veg
- Anti-oxidants
Most important risk factor of gastric cancer
Helicobacter pylori infection
What does h-pylori infection of the antrum cause?
- Hypergastrinaemia
- Duodenal ulcers
What does h-pylori infection of the corpus cause?
- Reduced acid secretion
- Hypochlorhydria
Treatment of h-pylori infection
- Triple therapy:
> Amoxicillin
> Clarithromycin
> Proton pump inhibitor
H-pylori equation converting urea to bicarbonate
C=O(NH2)2 + H+ + 2H2O –> HCO3- + 2NH4+
How does h-pylori infection of the corpus cause hypochlorhydria?
IL-1b down regulates gastrin
What is hereditary diffuse gastric cancer (HDGC) caused by?
Germline mutations in the CDH1 gene
What is E-cadherin?
Main transmembrane protein in adherens junction (cement in a brick wall)
Why is an E-cadherin deficient cancer worse?
Cells are not connected to metastasise to more locations
What causes E-cadherin repression?
- Epigenetic events
- Promoter hypermethylation
- EMT regulators (snail/slug)
Risk factors of colorectal cancer
- Increased red/processes meat
- Decreased fish
- Decreased fibre
- Obesity
- Decreased physical activity
- Alcohol
- Decreased aspirin/other NSAIDs
Types of colorectal cancer
- Sporadic
- Familial (FAP + HNPCC)
What is familial adenomatous polyposis coli (FAP) and what is it caused by?
- Multiple benign adenomatous polyps at an early age
- Mutated APC gene on chromosome 5q21
How is familial adenomatous polyposis coli treated?
Prophylactic surgery
Types of polyps that can arise from GI mucosa
- Adenomatous (become cancer)
- Serrated (less risk)
- Non-neoplastic (less risk)
What does the National Bowel Cancer Screening Program aim to identify?
Asymptomatic individuals with potentially curable disease
What test does the National Bowel Cancer Screening Program use, and what are the results of this?
- Faecal occult blood test
- 1.9% have +ve test and get colonoscopy
What is drug repurposing?
Using drugs intended for 1 purpose for a different purpose (usually old so cheaper)
How can metformin be used to treat colorectal cancer?
Suppressor of growth of the cancer
