7.6 Cancers of the Digestive System Flashcards
True or false: the mechanism of chronic liver disease is thought to be entirely separate from hepatocellular carcinoma
- False
- Most HCC arises on a background of chronic liver disease, and emerges with development of cirrhosis
List three classes of factors that are thought to occur with the onset of HCC, and give examples
- Toxicity (alcohol, aflatoxin)
- Viral infection (Hep B/C)
- Metabolic disease (hereditary haemochromatosis, alpha 1 antitrypsin deficiency)
List three mutations that may cause Hepatocellular Carcinoma
- Activation of B-catenin
- Inactivation of p53
- Increase in IL-6
List three kinds of lesions that may act as precursors for HCC
- Hepatocellular adenoma
- Dysplastic nodules
- Diffuse cell changes
What are hepatocellular adenomas? Are they more common in men or women? What medication are they associated with?
- Benign lesions of the liver; arise in non-cirrhotic liver
- More common in women
- Associated w/ OCP
What are the two types of dysplastic nodules in the liver? Which is more likely to progress to HCC?
- High grade and low grade nodules
- High grade is more likely to progress
CRC is the _____ most common type of cancer in Australia. It is more common in men/women, and almost all are _______carcinomas
- Third most common
- More common in men
- Almost all are adenocarcinomas
Modifiable risk factors for CRC
- Smoking
- Obesity
- Processed meat
- Alcohol
- Low fibre, high refined carbs
List three protective factors for colorectal cancer
- Vegetarian diet
- High fibre diet
- NSAIDs
What is familial adenomatous polyposis (FAP)? What is its genetic nature? What is the prognosis?
- Genetically, it is autosomal dominant (caused by mutation in APC gene)
- Causes many adenomas of the colon, prophylactic colectomy indicated
Explain the pathophys of Lynch Syndrome. What is it also called?
- Mutation in mismatch repair, causing mutations in microsatellite DNA regions affecting areas of DNA that control cell replication
- Also called Hereditary Non-Polyposis Colorectal Cancer (HNPCC)
What is the genetic basis of HNPCC/Lynch Syndrome?
- Patients inherit one mutant gene (usually of MSH2 or MLH1
- These are mismatch repair genes (what’s the link to pathophysiology?)
- When the second copy is lost, cell growth becomes out of control
Familial Adenomatous Polyposis typifies which aetiological mechanism of CRC?
Adenoma-carcinoma progression
What is the most common mechanism of CRC pathogenesis?
Progression from adenomatous polyps
List some non-modifiable risk factors for colorectal cancer
- Family history (closer = worse)
- FAP/HNPCC
- IBD
- Increasing age
- African descent
