PTEN and nonpapillary renal cell carcinoma: Overexpressed SPOP in ccRCC cells promotes proliferation and inhibits apoptosis through the ubiquitin–proteasome-mediated degradation of phosphatase and tensin homolog (PTEN), dual-specificity phosphatase 7 (DUSP7), death domain-associated protein (DAXX), and Sonic hedgehog (SHH) transcription factor glioma-associated oncogene homolog 2 (GLI2).