THBS1 and melanoma: Some of these genes had already been described in earlier studies as being down-regulated during melanoma progression: COL17A1 [15,18], DSC3 [15,18], KLK7 [10,15], SLPI and KLK8 [18], or over-expressed, e.g. CCL20 [55], THBS1 [55] and THBS4 [15].