system
Given the following post, respond as if you're commenting on Reddit:
human
Can cancer happen in any organ?

I've never heard of renal cancer or heart cancer or bladder cancer, but is that just because they're incredibly rare?
gpt
Theoretically speaking, any organ or tissue type can become cancerous.

Kidney cancer (such as clear cell renal cell carcinoma) and bladder cancer are uncommon cancers, but they are not extremely rare. In the US, there are about 70k new cases of kidney cancer every year, and about 80k new cases of bladder cancer every year.

Heart cancer exists, but it is **extremely** rare.