a blush?

[HaraKiriBlade]

It began with his parents. First his father, diagnosed with liver cancer, a blush of wild cells diffusing.

I looked up the dictionary for 'blush', for the word in this sentence didn't go with what I know it is, which is "reddening (of face, usually)". Still couldn't figure out what it means in this sentence. I can probably just ignore the word and still get the gist of the sentence, but by doing so this will probably stick to the back of my head for the rest of my reading session. Help is much appreciated.

[2utopian]

The wild cells are red in color.