Alpha-dystroglycan staining pattern and mortality in patients undergoing radical prostatectomy with lymph node positive prostate cancer.

Introduction: Dystroglycan (DG) is a cell surface receptor for extracellular matrix proteins involved in tissue mechanical stability and matrix organization. Initial work has demonstrated that alpha-DG expression is decreased in many types of adenocarcinoma, including prostate, and potentially associated with the development of metastatic disease. However, the consistency between prostate and lymph node alpha-DG staining has not been previously reported. In addition, identification of an immunohistochemical marker associated with prostate cancer grade, stage, need for adjuvant or salvage therapy and mortality would have potential clinical value.

Materials And Methods: Node positive, margin negative radical prostatectomy specimens at a single institution from 1982 to 2012 were reviewed and identified 35 prostate specimens, including 26 patients with available tissue from both the primary prostatectomy and lymph node specimens. The expression levels of the alpha-DG subunit were analyzed using immunohistochemistry and graded from 0 to 4. Survival was compared in different staining pattern groups.

Results: Strength of alpha-DG staining was found to be consistent between prostate and lymph node specimens (p < 0.004). The median overall survival was shorter in those without alpha-DG staining in the prostate compared to those with positive staining, but this difference was not statistically significant (13.2 years versus 19.4 years, p = 0.21). In addition, negative staining was associated with higher mean PSA, pathologic T stage, Gleason grade and the need for adjuvant or salvage therapy compared to positive group but none reached statistical significance (16.06 ng/mL versus 11.67 ng/mL, p = 0.79; 89% versus 68%, p = 0.38; 33.3% versus 23.1%, p = 0.66; 88.9% versus 76.9%, p = 0.44).

Conclusions: DG expression by immunohistochemistry staining was consistent between prostate and metastatic lymph node specimens. In a small cohort of prostate cancer patients with margin negative but node positive disease, DG staining was not associated with Gleason grade or with overall mortality.