PRCC and nonpapillary renal cell carcinoma: Among the risk factors, high expression of ABCB8 (logrank P = 1.2*10–5, HR 1.99, CI 1.45–2.73) and ABCB9 (logrank P = 4.2*10–7, HR 2.14, CI 1.58–2.88) were strong predictors of poor prognosis in ccRCC, while ABCB6 correlated with reduced survival in HCC (logrank P = 9.5*10–7, HR 2.36, CI 1.66–3.36) and PRCC (logrank P = 2.8*10–5, HR 3.34, CI 1.84–6.06).