I've seen those ads. It's pretty unlikely that it will substantially increase your cancer risk. I would also mention that while there is some science behind their claims, the studies they put on their site are insufficient (n=120 people, t=8 weeks of study) to make any medically valid claims, and the efficacy of the treatment (consuming NAD+ and plant sterols) hasn't been clinically proven to have a positive effect on human health. They also don't claim the participants saw a benefit, just that their NAD+ levels were elevated

I am personally bullish on the thought process behind NAD+ [1], but I probably wouldn't buy a consumer product for it today without some serious clinical proof. Caveat Emptor.

1 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4112140/

Disclaimer: I'm involved in the business side of the aging industry, but I only have a BSc in Genetics/Biochem, not a PhD.