The endocrine and epigenetic impact of persistent cow milk consumption on prostate carcinogenesis

Abstract

This review analyzes the potential impact of milk-induced signal transduction on the pathogenesis of prostate cancer (PCa). Articles in PubMed until November 2021 reporting on milk intake and PCa were reviewed. Epidemiological studies identified commercial cow milk consumption as a potential risk factor of PCa. The potential impact of cow milk consumption on the pathogenesis of PCa may already begin during fetal and pubertal prostate growth, critical windows with increased vulnerability. Milk is a promotor of growth and anabolism via activating insulin-like growth factor-1 (IGF-1)/phosphatidylinositol-3 kinase (PI3K)/AKT/mechanistic target of rapamycin complex 1 (mTORC1) signaling. Estrogens, major steroid hormone components of commercial milk of persistently pregnant dairy cows, activate IGF-1 and mTORC1. Milk-derived signaling synergizes with common driver mutations of the PI3K/AKT/mTORC1 signaling pathway that intersect with androgen receptor, MFG-E8, MAPK, RUNX2, MDM4, TP53, and WNT signaling, respectively. Potential exogenously induced drivers of PCa are milk-induced elevations of growth hormone, IGF-1, MFG-E8, estrogens, phytanic acid, and aflatoxins, as well as milk exosome-derived oncogenic microRNAs including miR-148a, miR-21, and miR-29b. Commercial cow milk intake, especially the consumption of pasteurized milk, which represents the closest replica of native milk, activates PI3K-AKTmTORC1 signaling via cow milk’s endocrine and epigenetic modes of action. Vulnerable periods for adverse nutrigenomic impacts on prostate health appear to be the fetal and pubertal growth periods, potentially priming the initiation of PCa. Cow milk-mediated overactivation of PI3K-AKT-mTORC1 signaling synergizes with the most common genetic deviations in PCa, promoting PCa initiation, progression, and early recurrence.