Strictly speaking, contagious cancer is a thing, but not in humans. See https://en.wikipedia.org/wiki/Canine_transmissible_venereal_tumor https://en.wikipedia.o

Strictly speaking, contagious cancer is a thing, but not in humans. See https://en.wikipedia.org/wiki/Canine_transmissible_venereal_tumor https://en.wikipedia.org/wiki/Canine_transmissible_venereal_...