system
Given the following post, respond as if you're commenting on Reddit:
human
Can plants get cancer from the sun? 

Can plants get cancer from the sun?
gpt
Basically, plants don't really get cancer as we think of it.  They can get uncontrolled growths, but they are more like our benign tumors, like warts. They don't kill the plant, generally. There are several big reasons for this:

1. Every plant cell is basically glued to its neighbors.  They have cell walls that provide structural integrity and hold the cell in place.  What that means is that you don't get cells moving around in a circulatory system like humans have.  So cancer can't really spread in plants.  With a few exceptions (brain tumors, other inoperable locations), cancer in humans that doesn't spread to distant sites isn't really that dangerous.  It's very rarely the primary tumor that kills people, it's the spread of the tumor to distant sites that kills.

2.  The cells that get hit by the sun in a plant are usually non-growing cells.  Their dividing cells, meristem cells, are hidden away from the sun pretty well.  So by the time plant cells are getting bombarded by UV, they have already stopped dividing and are glued in place.  That makes it a lot harder for them to re-enter the cell cycle and start causing problems.