system
Given the following post, respond as if you're commenting on Reddit:
human
How is feline leukemia contagious but human leukemia isnt?

I recently learned that feline leukemia is contagious but can't figure out what makes it contagious when the human version isnt.
gpt
It sounds like you're thinking of feline leukemia virus, which is a virus that causes leukemia. As a general rule, cancers including leukemias are not contagious, but if they are caused by a contagious virus, cases of cancer will spread. This is analogous to HPV in humans, which is sexually transmitted and causes cervical cancer. Someone with just cervical cancer won't be able to pass it to someone else, but if their cervical cancer is caused by HPV, they can pass on the HPV, which can lead to cancer in new hosts.