Immunohistochemical results (Supplementary Figure S3B) in HPA database also showed that the moderate or high staining intensity and cell quantity (>75%) of these four genes (UBA1, S100A13, SH3KBP1 and NISCH) in PC tissues contrasted sharply with the lack or low staining intensity and small quantity (<75%) in normal tissues, while COPS7A presented high expression level in both normal and tumor tissue. Here, COPS7A is linked to pachyonychia congenita.