Prognostic significance of RCAS1 expression in relation to the infiltration of dendritic cells and lymphocytes in patients with esophageal carcinoma.

RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) expression was determined in 107 esophageal carcinoma patients by immunohistochemical procedures and compared with tumor infiltrating lymphocyte (TIL) and dendritic cell (DC) infiltration to evaluate the effect of RCAS1 on immune responses in esophageal carcinoma. RCAS1 immunoreactivity was detected in 59 of 107 patients (55.1%). RCAS1 expression was significantly correlated with the depth of invasion, lymph node metastasis, and histologic stage. RCAS1 expression tended to be correlated with a lower TIL density in tumors with marked DC infiltration. The survival time for patients with RCAS1-negative tumors was significantly longer than that for patients with RCAS1-positive tumors. Especially, the prognosis was predicted by RCAS1 in cases with marked DC infiltration. Multivariate analysis revealed that RCAS1 expression was an independent prognostic factor. RCAS1 expression may play an important role in evading the immunological defense mechanisms in esophageal carcinoma.