BPV E5 induces recruitment of GRB2 to activated PDGFβR (pPDGFβR), contributing to cell transformation in vitro [22]; furthermore, pPDGFβR recruits GRB2-Sos1 which promote Ras activation in bovine urinary bladder cancer, suggesting a role of this pathway in BPV-induced carcinogenesis [25]. The gene discussed is GRB2; the disease is urinary bladder cancer.