Figure 1

(a) Localization of the FISH probes used for detection PTEN deletion and intragenic breaks. For detection of PTEN deletion, a PTEN deletion probe covering the entire PTEN gene and 3′ adjacent DNA, and a spectrum green-labeled centromere 10 control probe (data not shown), were co-hybridized. For detection of PTEN breakage, two differentially labeled probes corresponding to the 5′ and 3′ edges of PTEN were co-hybridized. (b) Examples of PTEN aberrations as detected by FISH. (I–III) Examples of the deletion probe: (I) normal copy number with two red PTEN signals and two green centromere 10 signals, (II) heterozygous deletion of PTEN showing loss of one red signal, but two green centromere signals, (III) homozygous deletion of PTEN lacking PTEN signals but showing two green centromere 10 signals. (IV–VI) Examples of the break-apart probe: (IV) intact PTEN as indicated by presence of two adjacent red (3′ PTEN) and green (5′ PTEN) signals, (V) translocation of PTEN showing one normal, adjacent red/green signal and a split of the second one into clearly separated green and red signals, (VI) heterozygous deletion of one allele and translocation of the remaining allele.