S100A4 and neoplasm: The data showed that all six samples were positive for ACTA2, S100A4, PDGFRA, FAP, IL-6 and P4HA1. This confirms that the cells are activated fibroblasts, especially based on the high expression of S100A4, PDGFRA and IL-6 in all samples.26–28 Gene expression levels were compared between the samples and HDFs and also between the different tumour fibroblast populations, which showed varying levels of expression.