16 GI cancers

Question 1

What are the 2 main types of GI cancers

Answer 1

Adenocarcinoma (often from Barrett’s M)

Squamous Cell Cancer

Question 2

How would we test those with Barrett’s to see if they have ADC?

Answer 2

sponge on a string mate for a biopsy

Question 3

What proportion of Barrett’s patients have ADC, and where is the research directed?

Answer 3

15%
the research is going into developing a biomarker of cancer risk in those with barrett’s, which owuld save a lot of money on endoscopy

Question 4

What are the epithelial cell changes occuring from normal cells to ADC?

Answer 4

normal stratified squamous
BM - columnar simple
Dysplasia - bigger nucleus, chromosomal gains
ADC - even bigger nucleus, more chromosomal gains

Question 5

Generally, what might promote the risk of ADC?

Answer 5

anything that promotes reflux

Question 6

What might suppress the risk of oesophageal cancer?

Answer 6

H. Pylori

decreased stomach H+, reducing the likelihood of reflux

Question 7

How does H.Pylori achieve its’ functions?

Answer 7

releases exotoxins, like urea, which converts stomach acid into bicarbonate, neutralising its’ local niche
also secretes mucinase, allowing them to attach to the epithelium to mount an inflammatory response (mediated by IL-6) to protect them.

Question 8

What is E-cadherin?

What might happen if it’s mutated?

Answer 8

transmembrane protein in the adherins junctino, forming a zip between 2 cells
in mutation, cell integration is limited, and cells become more motile and invasive during proliferation
Hereditary Diffuse Gastric Cancer (HDGC)
cells that wouldn’t normally produce E-cadherin now begin to produce it, to stick together

Question 9

What might cause E-Cadherin repression?

Answer 9

epigenetic events
promotor hypermethylation
EMT (epithelial mesenchymal transition) regulators

Question 10

How might we suppress E-Cadherin?

Answer 10

slug and snail are EMT regulators, with slug/snail the epithelial cells grown in culture are more spindly, and hence more likely to metastatise

Question 11

What use might there be to understanding what enduces EMT regulators?

Answer 11

potential therapies

Question 12

What sort of lifestyle is colorectal cancer associated with?

Answer 12

western lifestyle, with red and processed meats

Question 13

What are the 2 main types of colorectal cancer?

Answer 13

Sporadic

Familial (people tend to be young)FAP

Question 14

What is FAP?

Answer 14

Familial adenomatous polyposis coli

the polyps can develop into coli

Question 15

How might FAP be treated?

Answer 15

prophylactectomy, reducing their risk of developing FAP elsewhere

Question 16

What is the difference between cancerous colonic cells and normal colonic cells?

Answer 16

non cancerous cells use APC to phosphorylate proteins like beta-catenin, preventing them from switching on oncogenes, this is inhibited in cancerous colonic cells

Question 17

How will nuclear beta-catenin molecules affect matastasis?

Answer 17

beta-catenin presence in the nucleus will increase