TGFB1 and skin neoplasm: In order to better understand the role of TGF-β/activin signalling in human skin tumours (hereafter referred to as TGF-β signalling for simplicity), we characterise the expression of nuclear PO4-SMAD2 and PO4-SMAD3 as markers of endogenous canonical TGF-β signalling activity within normal human skin and primary human cSCC samples.