Prognostic significance of professional antigen presenting cells according to morphological subtype of periampullary adenocarcinoma.

Abstract

121 Background: Dendritic cells (DCs) and macrophages play vital roles in tumorigenesis and may, depending on the context, promote or inhibit tumor progression. In this study, we examined the prognostic significance of DCs and macrophages in periampullary adenocarcinoma, with particular reference to morphological type. Methods: Immune cell-specific expression of CD68, CD163 and CD1a was analysed by immunohistochemistry on tissue microarrays with tumours from 175 consecutive cases of periampullary adenocarcinoma, 110 of pancreatobiliary type (PB-type) and 65 of intestinal type (I-type) morphology. Kaplan-Meier and Cox regression analysis were applied to determine the impact of the investigated cells on 5-year overall survival (OS). Results: Low density of CD68+ cells or CD163 + cells was significantly associated with an improved 5-year OS in unadjusted Cox regression analysis in the entire cohort (HR = 1.66; 95% CI 1.05-2.63 and HR = 1.84; 95 % CI 1.09-3.09, respectively), but not in adjusted analysis or in strata according to subtype. CD1a+ cell density was not prognostic in entire cohort or in I-type tumours. However, in PB-type tumors, high CD1a+ cell density was significantly associated with a reduced OS in unadjusted as well as in adjusted analysis (HR = 2.09; 95% CI 1.07-4.09 and HR = 2.35; 95% CI 1.13-4.87). The prognostic value of the investigated markers did not differ in strata according to adjuvant chemotherapy, neither in the entire cohort nor according to morphological type. Conclusions: The results from study demonstrate that the prognostic significance of dendritic cells, but not macrophages, differs by morphological subtype in periampullary adenocarcinoma. Hence, morphological subtype is an important factor to consider in studies on the prognostic and predictive role of the immune microenvironment in these types of cancer.