PCNA and cancer: A number of key players in ccRCC are spotted in the network with PCNA and SOX9 as hub proteins controlling the operations of many neighboring proteins like POLD3, HUS1B and MNX1. PCNA is a well known molecular marker for proliferation14 and SOX9 is known to be upregulated in metastatic renal cell carcinoma and causes drug resistance in cancer by activating Raf/MEK/ERK pathway15.