In 14 patients with WHO/ISUP grade 2/3 clear cell RCC with venous invasion, the expression of main EMT markers (the miR-200 family, miR-205, SNAI1/2, TWIST1, ZEB2, and CDH1) was analyzed by qPCR in the selected tumour regions—the tumour centre (TC), the tumour periphery (TP), the venous tumour thrombus (VTT)—and compared to the corresponding non-neoplastic kidney tissue (N). The gene discussed is SNAI1; the disease is neoplasm.