Jiang, Strand, Fernandez et al. 351 Figure 4. Array–comparative genomic hybridization (array-CGH) and differential gene locus mapping (DIGMAP) analysis of NHPrE0 and BHPrE0 primary cells and derivative NHPrE1 and BHPrE1 cell lines. A: Array-CGH of NHPrE0 and BHPrE0 lines reveal a genome with no prominent unbalanced events; karyotypes resemble ‘‘normal.’’ In contrast, the derivative cell lines (BHPrE1 and NHPrE1) show more extensive genomic rearrangements. B: Converted DIGMAP data showing alterations in PTEN (ampliﬁed in NHPrE1), CTNNB1 (b-catenin ampliﬁed in BHPrE1), TERT, CDKN2A (p16), and TP53, which facilitate spontaneous immortalization in both lines. All array-CGH data have been deposited at the GEO database (accession number GSE18122). Abbreviations: BHPrE0, primary cultured benign human prostate epithelial cells isolated from a prostate surgical sample; BHPrE1, a spontaneously immortalized benign human prostate epithelial cell line from BHPrE0; NHPrE0 (NHP8), primary cultured ‘‘normal’’ human prostate epithelial cells isolated from a donated, 41-year-old, healthy, male prostate; NHPrE1: a spon- taneously immortalized ‘‘normal’’ human prostate epithelial cell line, that was established from parent NHPrE0 cells. and CTNNB1 (b-catenin) was ampliﬁed in BHPrE1 cells (Fig. 4B). These data support the concept that PTEN may be involved in some way in maintaining progenitor cell status [29]. TERT, CDKN2A (p16), and TP53 status in both cell lines (Fig. 4B) also supported the observed phenotypes during cellular immortalization [19]. An extended DIGMAP analysis www.StemCells.com