[mikepurvis]

Right, but that's within a single host isn't it? Like patient A gets that mutation and succumbs, that sucks, but the stronger cancer cells don't them jump to patient B the way antibiotic-resistant bacteria do.

(barring the transmissible cancers article that your sibling comment linked to, but that's not the common case)

[MontyCarloHall]

Sure, but my point is that convergent selective pressure across different individuals' tumors is strong enough that they independently arrive on the same resistance mechanisms to a given therapy, e.g. [0]. Just like if you performed the same bacterial antibiotic resistance experiment [1] across multiple independent trials, you'd repeatedly get the same result.

[0] https://pmc.ncbi.nlm.nih.gov/articles/PMC2538882/

[1] https://news.ycombinator.com/item?id=48505231#48507925