Diagnostic value of cyclin D1 immunohistochemistry in differentiating malignant mesothelioma from reactive mesothelial proliferation

Abstract

Introduction

Although morphologic assessment carries utmost importance in differentiating malignant mesotheliomas (MM) from reactive mesothelial proliferations (RMP), sometimes it may fail to clearly differentiate between these two entities. The aim of this study is to evaluate the potential role of cyclin D1 immunohistochemistry in this differentiation.

Material and methods

Eighty cases (40 MM, 40 RMP) were examined. Nuclear staining of the mesothelial cells was evaluated after cyclin D1 immunostaining. Immunostaining was scored according to the percentage of immunopositive cells (0 %, 1–25 %; 26–50 %; 51–75 %; 76–100 %).

Results

For MMs, 24/40 (60 %) cases demonstrated >50 % staining, with 13/24 in the 51–75 %, 11/24 in the >75 % range. RMPs generally showed no staining (27/40 cases) or 1–25 % staining (11/40 cases) with no cases showing >50 % staining. There was a statistically significant difference between RMP and MM groups according to Cyclin D1 staining percentage (p = 0.001). When 50 % was set as the cut-off value for Cyclin D1 staining, cyclin D1 immunohistochemistry had 60 % sensitivity, 100 % specificity and 80 % accuracy in differential diagnosis between MM and RMP.

Conclusion

In the diagnosis of MM, immunostaining of >50 % of the cells with cyclin D1 is a useful adjunct to morphologic assessment. Although cyclin D1 immunostaining showed high specificity when 50 % immunopositivity was set as a cut-off value in the differentiation between MM and RMP, its sensitivity and accuracy were relatively low. Validation of diagnostic utility of cyclin D1 immunohistochemistry based on the results of relevant prospective studies is necessary before its clinical application.