CDKN2A and neoplasm: However, food intake was comparable between p16+/+ and p16−/− FVB mice at 8 weeks (before weight differences were observed), 18 weeks (at the time weight differences were observed), and 52 weeks (after body weights started to differ) (Fig. 1B), indicating that p16Ink4a deficiency does not induce anorexia due to tumor growth.