Former FDA Commissioner Scott Gottlieb told CNBC he isn’t convinced that vaping nicotine is carcinogenic, calling out a study that pointed toward the opposite conclusion.

“I’m skeptical that nicotine causes cancer,” Gottlieb, a former physician, said Monday on “Squawk Box.” “It might be a tumor promoter, [researchers] have said that there’s a potential that nicotine is a tumor promoter, but it doesn’t cause cancer.”

Gottlieb was reacting to a study released last Monday that said e-cigarette vapor with nicotine causes lung cancer and potentially bladder cancer in mice, damaging their DNA and leading researchers at New York University to conclude that vaping is likely “very harmful” to humans as well.

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