PRCC and nonpapillary renal cell carcinoma: Furthermore, the Th2 gene signature (related to T-lymphocyte regulatory activity) was shown to be significantly upregulated in most of ccRCC, in all pRCC with a CpG island methylator phenotype (also known as CIMP-pRCC), and in some pRCC and chRCC; this signature may be considered a negative prognostic factor, regardless of tumor histologies [107].