The role of PTEN tumor suppressor pathway staining in carcinoma in situ of the bladder1

ObjectivesThe PI3k/Akt pathway has been associated with the development and progression of bladder tumors, with most studies focused on papillary or muscle-invasive tumors. We sought to characterize the expression patterns of the PI3K/Akt pathway in a large cohort of high-risk preinvasive carcinoma in situ (CIS) tumors of the bladder. Our goal was to understand whether PI3K/Akt pathway alterations associated with CIS resemble early- or late-stage bladder cancers.Material and methodsWe evaluated tissue specimens from 97 patients with CIS of the bladder, of which 14 had a concomitant papillary tumor. All patients were treated with intravesical bacillus Calmette-Guerin. All specimens were evaluated for PTEN, p-AKT, and p-S6 immunoreactivity. Markers were evaluated for percentage and intensity of staining and were scored using a 0 to 3+grading system.ResultsPTEN staining was noted as least intense in 67% of tumor specimens and 22% of normal urothelium. P-Akt and p-S6 had intense staining in 77% and 90% of tumor specimens vs. 44% and 68% in normal tissue, respectively. Low-intensity staining for PTEN at 12 months correlated with higher recurrence risk (P = 0.026).ConclusionWe describe a large cohort of CIS bladder tumors with decreased staining intensity of PTEN and increased staining intensity of p-AKT and p-S6, similar to high-grade and high-stage papillary tumors. Low-intensity staining of PTEN at 12 months was associated with an increased risk of recurrence.