GMO alone doesn't seem to me really a concern.

That can just mean it was engineered to be larger or taste sweeter or that it's a chimera of different plants.

Glyphosate resistance genetic modification is a different story. That glyphosate stuff (an herbicide) probably gives people cancer. For a product that's safe, Monsanto has spent quite a lot of time and resources rigging study results to say it's safe. There have even been a handful of legal settlements where they had to pay people who got cancer from Roundup, a ready to use Glyphosate formulation.

Can't hurt to wash, in any case.