HTR6 and nonpapillary renal cell carcinoma: Using Pearson’s correlation analysis, the DLK2 expression showed a strong positive correlation with the transforming growth factor β 1 (TGFβ1) (r = 0.502, p = 2.235 × 10−35), transmembrane protein 91 (TMEM91) (r = 0.4992, p = 6.114 × 10−35), HtrA serine peptidase 1 (HTRA1) (r = 0.4992, p = 6.114 × 10−35), AGAP2 antisense RNA 1 (AGAP2-AS1) (LOC100130776) (r = 0.4781, p = 8.475 × 10−32), and 5-Hydroxytryptamine receptor 6 (HTR6) (r = 0.478, p = 8.919 × 10−32) levels in human ccRCC tissues (Figure 6).