Definition
the transference of a bodily function or disease to another part of the body, specifically the development of a secondary area of disease remote from the original site, as with some cancers.
DFW's Sentence Of course, this is assuming one believes that information and spin are different things—and one of the dangers of partisan news's metastasis is the way it enables the conviction that the two aren't really distinct at all. Such a conviction, if it becomes endemic, alters democratic discourse from a "battle of ideas" to a battle of sales pitches for ideas (assuming, again, that one chooses to distinguish ideas from pitches, or actual guilt/innocence from lawyers' arguments, or binding commitments from the mere words "I promise," and so on and so forth).
My Sentence There she sat in a foul mood, glaring at the word with unrestrained loathing, and try as they might the thirty other occupants of Room 213 could not resist the disposition's metastasis, and so, quite naturally, a regrettable time was enjoyed by all.
01: DFW Source: The Host
02: Definition Source: Wiktionary and Wikipedia