MAPK3 and renal cell carcinoma: In the RCC cell line Caki‐2, GABA stimulation promotes cancer cell invasion via ERK1/2‐dependent upregulation of MMPs; an effect mediated mainly through the GABA‐B receptor.19 Thus, while DNA methylation changes may serve as prognostic markers in pRCC, they may also functionally influence the underlying biology of the disease.