Abstract
Abstract: :
Purpose: Primary intraocular lymphoma (PIOL) and CNS lymphoma (CNSL) are lethal neoplasms classified as extra-nodal large B-cell lymphomas. The five-year survival rate is 3-4% among treated patients. The purpose of this study is to characterize the immune-expression of PCNA in both PIOL and CNSL, and to correlate it with DNA Flow Cytometry in an effort to explain the aggressive behavior of these tumors. Methods: Eleven formalin-fixed, paraffin-embedded specimens, representing 4 PIOL and 7 CNSL, were immunostained with a monoclonal antibody against PCNA. A PCNA grading system of 0, + and ++ was applied to evaluate the intensity of the immunostain. Furthermore the percentage of PCNA stained cells was determined in ten high power fields and recorded as low (less than 30%), medium (from 30 to 70%), and high (more than 70%). All specimens were analyzed using DNA Flow Cytometry to measure the S-phase fraction (SPF) of the tumors. Mitotic figures were counted in ten high power fields. Results: All eleven specimens were PCNA positive. There was no difference in the degree of staining between the two groups. All of them had areas with + and ++ staining. In the CNSL group there were 2 cases with high number of PCNA positive cells (70%), 3 with medium (50%) and 2 with low (20 -30%). In the PIOL group 3 cases were graded as high (70% and 90%) and 1 as medium (40%). The SPF average was higher in the PIOL group (25.2 %) than in the CNSL group (15,8%) .The highest number of mitotic figures was found in the highest SPF tumor. This CNSL was also recorded as high PCNA. Conclusions: PCNA correlates with the SPF of both primary intraocular and CNS lymphomas and is therefore a useful immune marker of proliferation activity of neoplastic cells in these malignancies. PCNA activity represents a reliable indicator of the aggressive behavior of these lymphomas.
Keywords: 434 immunohistochemistry • 413 flow cytometry • 508 pathology techniques