PGP and prostate cancer: In order to investigate whether efflux ATP-binding cassette (ABC) transporter proteins were involved in the reversal of docetaxel and quercetin, the expression of P-gp was analyzed by Western blotting (Figure 7d), which showed that the expressions of P-gp in LNCaP/R and PC-3/R cells were significantly higher than that of their parental prostate cancer cells (p<0.05, Figure 7e & 7f).