Western diet and lifestyle risk factors and colon crypt expression of TGFα, TGFβ 1 , and TGFβRII in the Markers of Adenomatous Polyps II case‐control study

We examined whether normal colorectal tissue expression of TGFα and TGFβ 1 , potent autocrine/paracrine growth factors, and TGFβ receptor II (TGFβRII), a mediator of TGFβ signaling, are modulated by dietary factors in a feasibility study. In a random sample of 25 cases and 25 controls from a colonoscopy‐based case‐control study (n=200) of biomarkers of incident colorectal adenoma, we measured expression of growth factors in normal‐appearing rectal tissue using automated immunohistochemistry and image analysis. Diet was assessed with a Willett FFQ. Proportional differences in mean levels of TGFα, TGFβ 1 , TGFβRII, and the TGFα:TGFβ 1 and TGFβ 1 :TGFβRII ratios in cases vs. controls, were 77.4%, 25.4%, −7.7%, 141%, and −7.9%, respectively. Expression of TGFα was statistically significantly associated with mono: saturated fat ratio, alcohol and NSAID use; TGFβ 1 with estimated energy balance, fiber and sucrose intake; TGFβRII with an oxidative stress score, total energy intake (TEI), saturated fat, fiber, vitamin D, and zinc intake; TGFα:TGFβ 1 with overweight (BMI≥25), TEI, and sucrose intake; and TGFβ 1 :TGFβRII with mono: saturated fat ratio, obesity (BMI≥30), and TEI. These results suggest that autocrine/paracrine growth factor signaling may be involved in the progression of normal colonic mucosa to adenoma, and modulated by dietary factors related to energy balance, oxidative stress, and inflammation.