I wondered about this the other day and didn't get much of an answer: Are there first-hand research studies where we take a large sample of some animal (whales

I wondered about this the other day and didn't get much of an answer: Are there first-hand research studies where we take a large sample of some animal (whales / mole rats / whatever) and check the animals for cancer? Apart from the thought experiment of Peto's paradox, has someone actually taken the time and effort to document this? I'd be interested in reading some papers.