Oh how the Sun seeks to inform.
This is as you guessed a bollocks story.
Human cancer cells in mice?? This is a long way off phase 1 testing.
The link between chillis and gastric CA is quite complex. Again we are faced with a multi factorial disease and any causality neerds to be studied carefully. If chilli consumption was linked to gastric carcenoma we would expect to see epidemiologically a higher incidence in sub populations following this diet when compared with a comparitor group matched for ethnicity, socila class, age, tobacco consumption, alcohol consumption etc. I have not read of such multi variate comparison.
We do know that in the UK Capsiacin is licened by the MHRA for the topical relief of muscular skeletal pain associated with osteoarthritis. Probably working by placing a counter irritant effect on the skin and closing off the sensory gate. See Melzac and Wall's gate control theory of spinal nerve afferent sensory transmittion.
On a lighter note, I think chillis are possibly a good anti depressant as the world always seems a better place to me when I have a belly full of hot curry :P