For example, Barry et al. [11] found no unequivocal intrafocal heterogeneity in 32 multifocal prostate cancers, Furusato et al. [10] reported three tumors with signs of intrafocal heterogeneity in 81 multifocal cancers, Gumuskaya et al. [17] identified 7 % intrafocal heterogeneity in 44 ERG-positive tumor foci, Young et al. [16] found 4 % intrafocal heterogeneity in 78 ERG-positive tumor foci, and Svensson et al. [12] reported incidental intrafocal heterogeneity without specifying exact numbers. This evidence concerns the gene ERG and prostate cancer.