Cyclin D1 expression in ductal hyperplasia of usual type, atypical ductal hyperplasia and ductal carcinoma in situ of the breast: an immunohistochemical study

摘要

The distinction between atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS) is notoriously subjective with markedly different clinical implications with respect to risk of future development of invasive carcinoma and management. Previous studies have shown that cyclin D_1 expression is increased in DCIS but not ADH. The aim of this study was to determine whether immunohistochemical assessment of cyclin D_1 expression could be employed to aid distinction between ADH and DCIS of low nuclear grade. A series of cases of ductal hyperplasia of usual type (DH) (n-13) ADH (n=17) and DCIS of low nuclear grade (n=26) were staine D1 mmunohistochemically for cyclin D1 and Ki67 using monoclonal antibody NCL-CYCLIN D_1-GM. Since cyclin D_1 is a cell cycle-associated protein, all cases were also stained for Ki67 using monoclonal antibody NCL-Ki67. The proportion of cells staining positively for both antigens was assessed in each case. Expression of cyclin D_1 was significantly increased in ADH and DCIS compared to DH. A significantly higher proportion of cells stained positively with Ki67 for ADH and DCIS compared to DH. This study does not support the use of cyclin D_1 or Ki67 as an aid to histological differentiation between ADH and DCIS of low nuclear grade, but the results are in keeping with the view that the two conditions are biologically related; it is possible that cases assigned by the current criteria to the category ADH represent small foci of DCIS.