PDGFRB and melanoma: Based on databases EBI [17] and FANTOM5 [18] and recently published data, human melanoma A-375 [19] and human embryonic kidney 293T [20] cell lines were preliminarily considered to be PDGFRβ-negative, while murine colon carcinoma CT26 [21] and murine embryonic fibroblasts NIH/3T3 [22] cell lines were assumed to be PDGFRβ-positive.