MAPK3 and neoplasm: Although the extracts analysed by Western blots never represent proteins from tumour cells only, but always also include proteins from stromal fibroblasts and, partly, myoepithelial or ductal epithelial cells which might also express activated kinases, we found correlations of p-ERK1/2 expression in Western blots with IHC p-ERK1/2 expression in tumour cells (P=0.030 and 0.048 for p-ERK1 and p-ERK2, respectively; not shown).