We note that among other cell lines of different prostate cancer subtypes (PCS) we examined, LNCaP cells (PCS2) behaved similarly to C4-2 in clustering assays and expressed low amounts of MMP-7 whereas two other highly aggressive cell lines, LNCaP RANKL (PCS not profiled) and PC3 (PCS3), both of which constitutively produce MMP-7, either failed to cluster or formed small clusters (Table S1) [29]. This evidence concerns the gene MMP7 and Familial prostate cancer.