We then analyzed by RT–PCR the mRNA level of EGFR and of a small number of proteins involved in its activation and/or having prognostic value in cancer diseases: MMP-2 and -9 [32,33]; uPA [34,35,36]; G Protein Coupled Receptor 1 (GPER1) [37,38,39]; Estrogen Related Receptor alpha (ERR-alpha) [39,40,41]; SRC [42]; LDH-A and -B [43]; HBEGF. Here, PPIB is linked to cancer.