Background: CD74 is known as a type II transmembrane glycoprotein that is associated with the major histocompatibility complex class II alpha and beta chains. Recent studies have demonstrated that the expression of CD74 is also linked to some forms of tumors. The present study was to assess the effect of CD74 expression on the prognosis of resectable pancreatic ductal adenocarcinoma (PDAC).
Methods: Forty-six patients who had received a curative resection of primary PDAC and postoperative chemotherapy were included in this study. Immunohistochemical staining was conducted of CD74 on paraffin-embedded tumor sample slices. The patients were grouped according to CD74 staining: CD74 (-): CD74 positive tumor cells<25%; and CD74 (+): CD74 positive tumor cells ≥25%. The correlation of CD74 expression level with clinicopathological features and cumulative survival rate was calculated.
Results: The numbers of CD74 (+) and (-) patients were 32 and 14, respectively. CD74 (+) patients showed a high rate of perineural invasion (P=0.007). The 3- and 5-year cumulative survival rates of CD74 (-) patients were significantly higher than those of CD74 (+) patients (62% and 41% vs 9% and 0%, P=0.000). Multivariate analysis showed that CD74 expression and lymphatic permeation were the independent prognostic indicators.
Conclusions: The overexpression of CD74 is a key factor associated with perineural invasion. Lower-stage (I and II) PDAC patients with CD74 overexpression have a poor prognosis even if they receive a curative resection. CD74 can be used as a prognostic indicator for resectable PDAC.