Comparative expression of immunohistochemical biomarkers in cribriform and pattern 4 non-cribriform prostatic adenocarcinoma

The morphology of Gleason 4 prostate cancer (PCa) can be subdivided into cribriform and non-cribriform patterns. A large body of evidence has shown that pattern 4 cribriform PCa (especially non-glomeruloid type) is associated with adverse pathologic features and clinical outcomes compared with non-cribriform pattern 4 PCa. The underlying mechanisms for the aggressiveness of cribriform PCa are not fully understood. The aim of this study is to compare the immunohistochemical expression of various biomarkers and to determine the potential proteins that may account for their biologic and clinical differences. A total of 14 biomarkers were studied. The number of non-glomeruloid cribriform PCa cases studied for each biomarker ranged from 18 to 74 and the number of non-cribriform pattern 4 PCa studied for each biomarker ranged from 29 to 112. We demonstrated that, compared with non-cribriform Gleason pattern 4 PCa, EGFR was significantly upregulated and standard CD44 (CD44s) was significantly downregulated in cribriform PCa; no significant differences were found in the expression of AR, NKX3.1, ERG, EZH2, p53, Rb, C-Myc, BCL2, p16, CyclinD1, Her2/Neu, and Synaptophysin between these two groups of pattern 4 PCa. The study also showed, compared to non-cribriform PCa, cribriform PCa presented with significantly higher serum PSA and more advanced tumor stage. The significant overexpression of EGFR and downregulation of CD44s in non-glomeruloid cribriform PCa may, at least, partly explain the unfavorable pathology and clinical results for this growth pattern. Given that EGFR targeted inhibitors are now available, the findings may also have significant therapeutic implications.