We first examined the series of patient-derived tRCC cell lines, where UOK145 cells expressing SFPQ-TFE3 showed a striking reduction in PAX8 protein expression compared to ccRCC cell lines, but nearly all tRCC cell lines showed some decrease in PAX2 expression compared to the average expression seen in ccRCC lines (Fig. 6G, H). Here, TFE3 is linked to nonpapillary renal cell carcinoma.