Figure 2

PTEN FISH results are highly concordant with PTEN immunohistochemistry (a) PTEN immunohistochemistry image ( × 200 magnification) demonstrating PTEN protein loss in tumor glands (arrow) and PTEN protein retention in nearby benign glands (arrowhead) (b) PTEN FISH image captured from the tumor in (a) demonstrates glands with homozygous PTEN gene loss (yellow signal; arrow and upper right panel) intermixed with glands with PTEN intact (yellow signal; arrowhead, lower right panel). Peri-centromeric control probes (red) as well as flanking gene probes WAPAL (green) and FAS (aqua) are intact in all cells. (c) PTEN immunohistochemistry image ( × 200 magnification) from a separate Gleason score 6 biopsy that was not upgraded at radical prostatectomy demonstrating focal loss of cytoplasmic PTEN protein in tumor glands (arrow). Adjacent tumor glands stain positively. (d) PTEN FISH image captured from tumor in (c) demonstrates lack of PTEN deletion in tumor cells throughout (inset). (e) PTEN immunohistochemistry image ( × 100) demonstrates PTEN protein loss in tumor glands (red outline) with PTEN protein retention in adjacent benign glands (blue outline). (f) Higher power ( × 630) image of boxed area from (e). Note the presence of apical membrane staining in glands with cytoplasmic PTEN loss (arrowhead). The biological significance of this membrane staining remains unclear in the context of homozygous deletion of the PTEN gene. (g) PTEN FISH image captured from region delineated in (e) demonstrates intermixed glands with hemizygous PTEN, WAPAL and FAS deletion (arrow, inset) and glands lacking PTEN deletion (arrowhead).