Gastric Cancer Flashcards
what are the hallmarks of cancer?
self sufficiency from growth signals, resistance to antigrowth signals, metastasis, tissue invasion and sustained angiogenesis (formation of new blood vessels)
What are the 2 types of oesophageal Cancer
Adenocarcinoma (ADC) and squamous cell carcinoma (SCC)
what are the risk factors for ADC?
Barret’s Metaplasia (therefore obesity, drugs that relax LOS etc), gender
what factors decrease risk of oesophageal cancer?
fruit, vegetables, antioxidants, H.Pylori (reduces risk of ADC if present in corpus due to it causing hypochloridria)
Where do ADC and SCC commonly occur?
SCC - distal 2/3 to the stomach, ADC proximal third to the LOS
Explain the factors that effect E-Cadherin expression and can lead to Gastric Cancer
E-Cadherin is a key cadherin in the cadherin zipper component of adherence junctions which holds cells together
Suppression of E cadherin can lead to EMT via:
inherited E cadherin mutation = hereditary diffuse type gastric carcinoma
other epigenetic events e.g. hypermethylation of promoters or expression of SNAIL and SLUG - EMT regulators that supress E cadherin expression
what are the risk factors for Gastric Cancer?
Red meat, aging, obesity and alcohol
What does FAP stand for in relation to inherited Gastric Cancer?
Familial Adenomatous Polyposis Coli
Explain the mechanism of FAP
Adenomatous Polyposis Coli (APC), is part of a family of proteins which bind to B-catenin in the cytoplasm to direct in to the ubiquitin proteasome pathway
if not bound B catenin bind to a TF which migrates into the nucleus and causes transcription of immediate early genes (cyclins) which drive uncontrolled cell proliferation
therefore APC binding stops this and is a tumour suppressor gene
inherited familial mutations in APC leads to uncontrolled cell proliferation, developing multiple begnin growths along the GI tract which can turn cancerous
what is the treatment for FAP?
removal of parts of the intestine via prophylactic surgery to prevent cancer, however pops can grow in other areas
Give an Example of why personalised genetic specific treatment is important when treating tumours?
cetuximab - binds to EGFR a RTK to prevent the activation of K RAS in tumours which causes uncontrolled cell proliferation
this treatment only works in tumours related to EGFR mutation / overexpression, in cases such as K RAS switch mutation so that it is always active this treatment is unhelpful
