TCF7L2 and type 2 diabetes mellitus: As shown by microarray analyses, mRNA levels of the Wnt/β‐catenin signalling target genes related to metabolic diseases, including TCF7L2, WISP‐1, IGF‐1 and PPARδ, were lower in the visceral adipose tissues from patients with T2DM than in tissues from non‐diabetic subjects (Figure 1A and B).