TCF7L1 and cancer: PIK3CA-mutant cancers displayed higher expression of 12 of the 17 Wnt genes compared to PIK3CA wild-type tumors, including five Wnt target genes (LEF1, MYCN, FZD7, SFRP2, and TNFRSF11B) and seven Wnt signaling components (TCF7L1, TCF7L2, CTNNB1, FZD4, SFRP1, WNT5A, and MSX2).