Immunohistochemical expression of PCNA and CD34 in colorectal adenomas and carcinomas using specified automated cellular image analysis system: A clinicopathologic study

Background/Aim: To evaluate the immunohistochemical expression of proliferating cell nuclear antigen (PCNA) and CD34 in colorectal adenomas and carcinomas, and to correlate this expression with different clinicopathologic parameters. Materials and Methods: The study was retrospectively designed. A total of 86 tissue samples, including 33 paraffin blocks from patients with colorectal adenomas, 33 paraffin blocks from patients with colorectal adenocarcinomas, and a control group of 20 samples of nontumerous colonic tissue, were included in the study. From each block, 3 sections of 5 ΅m thickness were taken, 1 section was stained with hematoxylin and eosin (H and E) and the other 2 sections were stained immunohistochemically for PCNA and CD34. Scoring of the immunohistochemical staining was performed using a specified automated cellular image analysis system (Digimizer). Results: PCNA expression was significantly increased in a sequence of normal mucosa-adenoma-carcinoma. It was significantly higher in adenomas ≥ 1 cm and those with severe dysplasia, and it showed a significant positive correlation with grade and lymph node involvement in colorectal carcinoma. CD34 showed significantly higher expression in carcinoma than adenoma and in adenoma than in the control group. CD34 expression showed a significant correlation with adenomas carrying severe dysplasia and large-sized adenomas (≥1cm). It was significantly correlated with tumor grade, lymphovascular invasion, and lymph node involvement in colorectal carcinoma. Conclusion: PCNA plays an important role in colorectal neoplastic progression and can be utilized as ancillary marker for the risk of malignant transformation in colorectal adenomas as it correlates with high grade dysplasia and size. Intratumoral quantification of the mean (A and N) of CD34 in colorectal carcinoma reflects the grade of tumors and can predict lymph node involvement and lymphovascular invasion, to make a useful additional prognostic factor