S100 as an immunohistochemically-detected marker with prognostic significance in endometrial carcinoma.

Background: Several studies have indicated that dendritic cells (DC) participate in anti-tumor immunity, possibly influencing the course of malignant disease. We tested whether tumor infiltration by S100+ DC could be a prognostic marker for endometrial cancer.

Materials And Methods: A retrospective study analyzing 115 tissue samples from patients with endometrial carcinoma and known histological grading as well as hormone receptor, Ki-67, Her-2/neu and p53 expression. Sections of paraffin-embedded endometrial tissue were immunohistochemically-stained with anti S100 antibody. Tumor infiltrating S100+ DC were counted via microscopic examination and calculated as S100+ DC per mm2 of tissue.

Results: Samples were divided into group 1: less than 10 S100+DC/mm2 (n = 44) and group 2: 10 or more S100+ DC/mm2 (n = 71). Correlation with clinico-pathological markers was calculated by Chi-square test. Compared to group 1, the DC-rich group 2 showed a higher level of differentiation (p=0.045), a lower overexpression of p53 (p=0.021) and less proliferation (p=0.028). DC infiltration was not correlated with Her-2/neu, hormone receptor status and FIGO-stage. Although no significant correlation could be seen, the DC-poor group samples seemed to correlate with a higher FIGO-stage compared to the DC-rich group. In uni- and multivariate analysis, DC infiltration proved to be a significant prognostic marker for adjusted survival but not for overall survival.

Conclusion: Our results indicate that the immunohistochemical determination of S100+ DC could contribute to the identification of a high-risk subgroup and, therefore, would be a favorable prognostic factor for endometrial carcinoma. Our observation that pronounced DC infiltration is associated with good prognosis points to an important role of the host's immune system response for the clinical course of endometrial cancer.