In the current study, we utilized the ECLIA to assess serum level of polyglutamylated DNAJC7 protein in RCC sera vs. those from healthy controls, benign kidney diseases and found astonish data, i.e., while there was almost no polyglutamylated modification in sera of health controls and non-tumor kidney diseases, RCC sera showed dramatic upregulation of polyglutamylated DNAJC7 protein. Here, DNAJC7 is linked to renal cell carcinoma.