Immunohistochemical Expression of M30, BCL-2, BAX, and Ki-67 in Pancreatic Ductal Adenocarcinoma: Association with Clinicopathological Features

Background: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with limited survival despite advances in diagnosis and treatment. Dysregulation of apoptosis and tumor cell proliferation is a fundamental feature of cancer biology. M30, BCL-2, and BAX reflect different aspects of apoptotic activity and regulation, whereas Ki-67 is a widely used marker of cellular proliferation. However, the clinicopathological significance of these markers in PDAC remains incompletely characterized. This study aimed to evaluate the immunohistochemical expression of M30, BCL-2, BAX, and Ki-67 in PDAC and to investigate their associations with established clinicopathological features. Methods: This retrospective study included 50 patients with surgically resected PDAC treated at Afyon Kocatepe University Medical Faculty Hospital between January 2003 and May 2015. Archived tumor specimens were evaluated by immunohistochemistry for M30, BCL-2, BAX, and Ki-67. M30 and Ki-67 expression were quantified according to the percentage of positive tumor cells, while BCL-2 and BAX expression were assessed using semiquantitative staining scores based on staining intensity and the proportion of positive tumor cells. Immunohistochemical findings were compared with sex, tumor differentiation, tumor size, lymphovascular invasion, perineural invasion, surgical margin status, tumor stage, lymph node metastasis, and clinical stage. Results: The study cohort comprised 30 male and 20 female patients, with a mean age of 62.12 ± 10.93 years. M30 expression was detected in 39 (78%) cases, whereas Ki-67 expression ranged from 10% to 85% of tumor cells. BCL-2 and BAX expression showed variable staining patterns. None of the four markers demonstrated a statistically significant association with tumor differentiation, tumor size, lymphovascular invasion, perineural invasion, surgical margin status, tumor stage, lymph node metastasis, or clinical stage. Conclusions: In this cohort of surgically resected PDAC, immunohistochemical expression of M30, BCL-2, BAX, and Ki-67 was not significantly associated with conventional clinicopathological indicators of tumor aggressiveness. These findings indicate that immunohistochemical assessment of individual apoptosis- and proliferation-related markers may not adequately reflect tumor aggressiveness or clinicopathological heterogeneity in PDAC. Further studies incorporating larger cohorts, standardized immunohistochemical assessment, and clinical outcome data are warranted to clarify their potential biological and prognostic significance.