The multidrug resistance-associated protein 4 (ABCC4) showed a predominant membrane staining pattern (Figure 3B and 3E), and was overexpressed in 82.9% (39 of 47 samples) of tumor cases and in 81.25% (13 of 16 samples) of PIN lesions. This evidence concerns the gene ABCC4 and prostate intraepithelial neoplasia.