Cancer of the GIT Flashcards
List 6 characteristic hallmarks of cancer.
1 - Evasion of apoptosis.
2 - Self-sufficiency in growth signals.
3 - Insensitivity to anti-growth signals.
4 - Tissue invasion and metastasis.
5 - Limitless replicative potential.
6 - Sustained angiogenesis.
List the two types of oesophageal cancer.
1 - Adenocarcinomas (ADCs).
2 - Squamous cell carcinomas (SCCs).
List 6 risk factors for oesophageal ADCs.
1 - Reflux and Barrett’s metaplasia.
2 - Gender.
3 - Age.
4 - Lower oesophageal sphincter (LOS) relaxing drugs.
5 - Obesity.
6 - Helicobacter pylori.
How do cells change in Barrett’s metaplasia?
Cells lining the oesophagus change from stratified squamous to simple columnar.
What is the most important risk factor for gastric cancers?
Helicobacter pylori.
List the areas of the stomach and briefly describe their locations.
1 - Cardia (oesophageal opening).
2 - Fundus (bulbous superior portion).
3 - Body / corpus.
4 - Antrum (inferior portion).
5 - Pylorus (funnels into duodenum).
What are the effects of H. pylori infection in the antrum of the stomach?
- Hypergastrinaemia.
- Duodenal ulcers.
What are the effects of H. pylori infection in the body of the stomach?
- Reduced acid secretion.
- Hypochlorhydria.
- Gastric ulcers.
What does treatment-triple therapy consist of?
1 - Amoxicillin (antibiotic).
2 - Clarithromycin (antibiotic).
3 - A proton pump inhibitor.
List 5 ways by which H. pylori cause its effects.
1 - Urease neutralises gastric acid, causing gastric mucosal injury by ammonia.
2 - Lipopolysaccharides cause inflammation.
3 - Type 4 secretion systems inject effectors that inhibit apoptosis.
4 - Secretory enzymes such as mucinase, protease and lipase cause mucosal injury.
5 - The exotoxin vacA causes mucosal injury.
What is hereditary diffuse gastric cancer?
An autosomal dominant susceptibility for diffuse gastric cancer that causes a thickening of the stomach wall.
What are the two histological types of adenocarcinoma?
Intestinal type and diffuse type.
What causes hereditary diffuse gastric cancer?
Germline mutations in the CDH1 gene.
What is e-cadherin?
A molecule that is important in the formatino of adherins junctions.
List the types of cell junctions.
1 - Tight junctions (zonula occludens).
2 - Adhering junctions (zonula adherens, desmosomes and hemidesmosomes).
3 - Gap junctions.
List 3 causes of e-cadherin repression.
1 - Epigenetic events.
2 - Promoter hypermethylation.
3 - Epithelial to mesenchymal transition (EMT) regulators.
What is epithelial to mesenchymal transition (EMT)?
The process whereby epithelial cells are transformed into mesenchymal cells.
List two risk factors for colorectal cancer.
1 - Older age.
2 - Meat intake.
3 - Obesity.
4 - Alcohol.
List 4 ways in which colorectal cancer risk can be reduced.
1 - High fibre intake.
2 - High fish consumption.
3 - Exercise.
4 - Aspirin and other NSAIDs.
What are the types of colorectal cancer?
Sporadic and familial.
List the types of familial colorectal cancer.
1 - Familial adenomatous polyposis (FAP).
2 - Hereditary nonpolyposis colorectal cancer (HNPCC) / Lynch syndrome.
How does familial adenomatous polyposis (FAP) cause colorectal cancer?
- The increased risk is due to polyp formation, which are benign but can become malignant.
- The polyp formation is due to a mutation to the APC (adenomatous polyposis coli) gene.
How does hereditary nonpolyposis colorectal cancer (HNPCC) cause colorectal cancer?
The increased risk is due to mutations that impair DNA mismatch repair.
How is familial adenomatous polyposis (FAP) treated?
Prophylactic surgery.
What is the difference between a carcinoma, a squamous cell carcinoma, an adenocarcinoma and an adenoma?
- A carcinoma originates from epithelial cells.
- A squamous cell carcinoma originates from squamous cells.
- An adenocarcinoma originates from glandular tissue.
- An adenoma is the benign counterpart to an adenocarcinoma.
List two drugs that can be used to treat colorectal cancer.
1 - Metformin.
2 - Cetuximab.
What role does iron play in the formation of cancer?
- Excess iron can contribute to tumour initiation and growth.
- Iron’s capacity to gain and lose electrons enables it to participate in free radical-generating reactions.
