[UnoriginalGuy]

I love how you cut off the sentence in order to mislead:

> While no epidemiological evidence supports that nicotine alone acts as a carcinogen in the formation of human cancer, research over the last decade has identified nicotine's carcinogenic potential in animal models and cell culture.

It then goes on to say:

> Nicotine has been noted to directly cause cancer through a number of different mechanisms such as the activation of MAP Kinases.[76] Indirectly, nicotine increases cholinergic signalling (and adrenergic signalling in the case of colon cancer[77]), thereby impeding apoptosis (programmed cell death), promoting tumor growth, and activating growth factors and cellular mitogenic factors such as 5-LOX, and EGF. Nicotine also promotes cancer growth by stimulating angiogenesis and neovascularization.[78][79] In one study, nicotine administered to mice with tumors caused increases in tumor size (twofold increase), metastasis (nine-fold increase), and tumor recurrence (threefold increase).

[mistercow]

While it was dishonest to cut the sentence off in the middle, the lack of epidemiological evidence basically puts nicotine in the same camp as a ton of other substances that have "carcinogenic potential" but aren't considered a risk. Basically, it's plausible that nicotine is carcinogenic to some degree, but with the carcinogenicity of tobacco explained entirely by other factors, there's no real reason to believe that it's a significant risk, especially for bystanders.

[cjh_]

I cannot upvote this enough, thank you for going to the effort of actually checking the source for the full claim.