PYCR1 and nonpapillary renal cell carcinoma: In ccRCC pathogenesis, PYCR1 exerts dual oncogenic functions by fueling tumor proliferation and metastatic dissemination through mTOR signaling activation while concurrently shaping the immune landscape via its correlation with the enhanced infiltration of activated CD4+ memory T cells—a paradoxical relationship suggesting metabolic–immune crosstalk within the tumor microenvironment [17].