TGFB1 and cancer: In this study, we also measured two growth factors, TGF‐β‐1 and PDGF‐AB, implicated in the pathogenesis of cancer (Silver, 1992; Meulmeester & Ten Dijke, 2011), which have previously been shown in observational studies to be reduced by long‐term severe CR in humans (Fontana et al., 2004; Meyer et al., 2006).