CYP3A4 and pure red-cell aplasia: Our previous nested case–control association studies found that the frequencies of the CYP3A4*1B and VDR TaqI TT genotypes are higher among BPH patients who subsequently develop PRCa than among BPH control patients (Odds ratio, OR: 5.2 and 5.16, respectively; Tayeb et al, 2002, submitted).