4.5. qRT-PCR
Cell lines 786-O for ccRCC and HK-2 for normal cells were extracted using the TRIzol method (Invitrogen Co., Carlsbad, CA, USA). The above two cell lines were purchased from a commercial company (Zhong Qiao Xin Zhou Biotechnology Co., Ltd., Beijing, China). For cDNA synthesis, a High Capacity RNA-to-cDNA kit (Toyobo Co., Ltd., Osaka, Japan) was used. 