As I'm an engineer, I couldn't help but look at the actual document referenced in that article. It is not demonstrating a clear link between microchips and cancer.
Please read the quote from that document below ( in bold ) -
They searched pubmed articles over a SIXTEEN year period and found a total 11 articles listed referring to microchips.
Three of those indicated no concern.
Two were centered on dogs who had developed tumors in or near the injection site, but it can't be said with any certainty they were related.
The remaining articles refer to lab rats. Consider the role of the lab rat.
They are subjected to all sorts of experimentation. That a handful developed cancer is not damning evidence in my mind.
The largest study of a group of 4000 + lab rats showed 0.8 % (less than one percent) developed cancer.
All 4000+ were microchipped (most all lab rats are). However, it can't be stated that they developed cancer because of the chip, or other reasons.
I'm not suggesting there is no possible relation.
But there is no actual correlation between microchips and cancer in this article or document.
From section 8.4
There have been no large-scale, statistically valid,
clinically controlled, experimental studies involving
microchip implants in dogs and cats, so we know very
little about their long-term safety. However, the fact that
we have not seen an epidemic of cancers in pets would
suggest that only a small number will be impacted. As the
chip-removal procedure may be both costly and invasive,
pet owners may wish to leave the implanted microchips
intact within their animals unless a problem surfaces.
Owners of pets that have been implanted should
regularly check the area around the chip for any abnormal
lumps or swelling. If something unusual is found, it should
be immediately reported to a veterinarian, and tests should
be done to rule out cancer. The pet owner may be the key
to detecting a problem in the early stages and saving the
life of a pet. In the two cases where dogs developed
tumors around and attached to implants, it was the owners'
astute eye and probing fingers that found the cancers, not
the veterinarian. The only indication that there was a
problem was the lump; all other laboratory tests came
back within normal ranges