The word "meme" was created by Dawkins to be similar to "gene", because they spread similarly. Cancer is, in a certain sense, a genetic disease, the result of the malfunction of genes caused by mutation. So, to continue the analogy, a badly mutated meme can be like cancer, and can spread like one.

https://en.wikipedia.org/wiki/Meme#Etymology

https://en.wikipedia.org/wiki/Cancer#Genetics