Finally, our study demonstrates that PDGFβR is activated thus binding downstream molecular partners in sarcoid-derived cell lines expressing BPV-1 E5; this activation results in Ras activation but not major phosphorylation of MEK and ERK kinases, suggesting that this signalling cascade may possibly cross-talk with other transduction pathways which had been found to be activated in BPV-induced tumours. This evidence concerns the gene MAP2K7 and neoplasm.