PDGFRB and neoplasm: Considering the presence of markers for tumour-associated fibroblasts such as αSMA (ACTA) and PDGFRB, we found that the ‘high collagen’ dataset segregated into groups with high and low MITF ‘signature’ gene expression, and this was inversely correlated with the expression of the fibroblast markers ACTA2 and PDGFRB (Fig. 5b).