system
Given the following post, respond as if you're commenting on Reddit:
human
Is there something special about hearts that make them resistant to cancer?

It seems like cancer affects every single organ in the body, but for every news story I’ve heard about cancer I don’t remember a single one discussing heart cancer, even in patients whose original cancer has metastasized to other areas of their body.

Is there something special about hearts that makes them cancer-proof? Or is heart cancer so lethal that it’s pointless to discuss treatment/cure?
gpt
The heart is muscle, and muscle isn't cancer-prone. The cells that get cancer are those that get replaced a lot. Cancer generally requires a couple of accumulated errors that knock out multiple safeguards against uncontrolled cell division. The cells that accumulate lots of errors are the ones with lots of turnover, which means lots of chances to make a mistake in copying DNA.

Most of the common cancers are carcinomas, which means they come from cells that line things (epithelium.) Linings are replaced frequently, so there's more room for error. Think of skin, wet pink parts of the body like the lung and colon, or glands like the prostate or in the breast. Alternately, there's blood cancers like leukemias and lymphomas, since bone marrow is also a place where new cells are being made at a ferocious pace.

Sarcomas, which affect muscle/bone/cartilage/fat/some other stuff, are WAY more rare. Muscle cells would rather grow than make new cells, and heart muscle is replaced very slowly. There are true heart cancers, but they're absurdly uncommon.