Objective: The aim of this study was to identify the immune response in sentinel lymph nodes (SLNs) of patients with endometrial and patients with cervical cancers by analyzing the number of S-100-, CD1a-, CD83-positive (+) dendritic cells that are the major antigen-presenting cells.

Methods: A total of 56 patients with early-stage cancer (n = 32, with cervical; n = 24, with endometrial cancer) underwent SLN biopsy. Sentinel lymph nodes and non-SLNs were stained with antibodies against S-100, CD1a, and CD83 as markers for dendritic cells to find out whether SLNs were immunomodulated compared with non-SLNs.

Results: The mean values of S-100(+) and CD1a(+) dendritic cells in both the tumor-free and the metastatic SLNs were significantly higher than those of both the tumor-free and the metastatic non-SLNs. When metastatic SLNs were compared with nonmetastatic SLNs, CD83(+) dendritic cells were found significantly more abundant in nonmetastatic SLNs.

Conclusions: Significantly higher numbers of S-100(+) and CD1a(+) dendritic cells in the SLNs compared with those in the non-SLNs may indicate that SLNs are the first sites of immunostimulation. Immunosupression may be the underlying factor for the metastatic involvement of SLNs, which might be secondary to the significantly decreased number of mature dendritic cells in metastatic SLNs compared with tumor-free SLNs.