MAPK3 and neoplasm: IHC staining on tumour sections of xenografts and metastasized organs demonstrated that the upregulation of BART1 significantly reduced the expression of PTEN (see Fig. 3d) but clearly increased the phosphorylation levels of p-Akt, p130Cas, p-Shc and p-ERK1/2 in 5-8F-BART1 tumours compared with the 5-8F-mock tumours (Fig. 4c).