Looking for a short story where hostile aliens are tricked into curing cancer

Question

This was a short story published in a collection of sci-fi short stories, at least as long ago as the eighties but probably a lot older, possibly even the fifties or sixties.

The gist of the story is that an astronaut is making first contact with aliens. They ask him to send a sample of flesh for research purposes. He sends it, then they return it to him (I can't remember why). The twist is, the astronaut knew all along the aliens were going to be hostile, and he sent them a sample of his cancerous tumor. The aliens infected it with a virus, thinking they were going to wipe out human life, but instead cured cancer. Hooray!

Anyway, if anyone knows what this story is, I'd love to read it again!

Answer 1

I believe you are thinking of "The Peacemaker", (also sometimes titled "The Life Hater") one of the Berserker stories by Fred Saberhagen. This one was published in 1964. There is a brief synopsis on this page:

The berserker asks for a cell sample, ostensibly to see if human cells really are so complex. In reality it uses the information from the cell sample to develop a biological warfare agent! The berserker says it is convinced, and will now serve humankind, and sends the pacifist back to his planet infected with the biowarfare agent, expecting the human to land and infect the entire planet. But the joke is on the berserker! The pacifist has cancer, and provided the robot with a cancer-stricken sample, so the infection is curing him instead of killing him! And his proximity to the berserker allowed him to gather valuable recon that will help the hastily assembled defense destroy the mechanical menace!