If I understand the article correctly, they are talking about the sarcomas. Those are the same ones they are trying to link to vaccinations. And from what I've heard from other vets, techs, those sarcomas can be caused by ANY needle poke whether filled with sterile water, vaccinations or microchips or just even appear by themselves randomly.

I think some people are getting overly paranoid about many coincidences. I can't count the number of microchipped pets (several hundered at least) we have at the hospital, many of them chipped years before I started working there, and not one single one has ever had any type of sarcoma even remotely related to a microchip.