However, having previously shown that PDGFRB is highly expressed on PDS tumor cells, but neither on differentiated or undifferentiated (sarcomatoid) cSCC1, the enrichment of “PI3K/AKT signaling in cancer” in PDS (Spearman correlation = 0.29, FDR = 3 × 10–4), which included PDGFRB as a receptor and PDGFD a as ligand, was of interest. The gene discussed is PDGFD; the disease is cancer.