Homing ösophagealer Karzinomzellen in Lymphknoten und ins Knochenmark — Rolle der CXCR4-Expression

Background: The chemokine and bone marrow homing receptor CXCR4 has been implicated in metastatic dissemination in different tumor types. In this study we investigated CXCR4 expression in esophageal cancer and the association with survival, lymph node and bone marrow micrometastasis. Methods: We retrospectively analyzed frozen tumor samples of 136 patients with completely resected esophageal cancer for CXCR4 expression by immunohistochemistry. Lymph node micrometastasis was determined by staining with mAb Ber-EP4, bone marrow micrometastasis by using pancyto-keratin mAb A45-B/B3. CXCR4 expression was correlated with these results and other clinicopathological features. Results: CXCR4 expression was found in 75 out of 136 (55%) esophageal tumors. Patients with positive immunostaining of CXCR4 had a significantly shorter overall and tumor-specific survival than patients without (p = 0.002; log-rank test). Further, CXCR4 expression significantly correlated with lymph node as well as bone marrow micrometastasis. Multivariate analysis identified CXCR4 expression as an independent prognostic factor (p = 0.001). Conclusion: CXCR4 expression is associated with a significantly worse outcome in esophageal cancer patients. Our results implicate a role for CXCR4 in systemic spread since expression correlates with lymph node and bone marrow micrometastasis and it could be a potential target for immunotherapy.