[Quiet Man Cometh]

Not a published book, but for amateur fiction, yes. It's like people riding unicorns instead of horses and calling it fantasy, with the only noticable difference being that the "horses" have horns. The characters would still get from point A to point B if the unicorns where something more mundane, especially if the unicorns did nothing but get the players from point A to point B. Put that on a plot sized scale and that's where genre becomes useless.

I read a short sci fi story where money was called "credits" and instead of paper bills people had "chips" and the term "Galactic Alliance" was used intead of (insert global police force's name here). It was billed as sci-fi, but the story itself with corrupt cops, prostitues, and blackmail could just as easily have happend downtown in the real world last week.