MMPs were initially thought to be produced solely by the tumour cell, but further investigation has also shown production by CAFs and the surrounding inflammatory cells.41 Recently, it has been shown that MMP9 could even lead to activation of EMT genes.42,43 In this way, it is plausible that the tumour stroma consisting of Rfs is involved in MMP9 upregulation and facilitate SCC invasion via EMT. The gene discussed is MMP9; the disease is neoplasm.