ARHGEF15 and neoplasm: The role of E5 in naturally occurring sarcoids has been largely investigated: E5 is found in molecular complex with the phosphorylated PDGFβ-r (pPDGFβ-r) in sarcoids and the high levels of pPDGFβ-r activate the PI3-K-Akt pathway and Grb2-Sos-Mek-Erk pathway (G Borzacchiello, personal observations) such as in bovine tumours [76].