Prognostic significance of serum sMICA levels in non-small cell lung cancer

OBJECTIVE: The soluble form of major histocompatibility complex class I-related chain A (MICA) is released from the surface of tumor cells of epithelial origin. Serum levels of soluble MHC class I-related chain A (sMICA) is related with the prognosis of various types of cancer. However, there are studies on the prognostic value of sMICA in non-small cell carcinoma (NSCLC). In this study, we retrospectively investigated the relationship between sMICA levels and clinical features of NSCLC, and we assessed the prognostic value of sMICA in NSCLC. PATIENTS AND METHODS: sMICA levels were detected in 207 NSCLC patients and 207 normal control individuals with using enzyme-linked immunosorbent assay (ELISA), and its associations with clinicopathological parameters were evaluated. Survival curves were compared using the Kaplan-Meier method and log-rank tests. Univariate Cox regression was used on each clinical covariate to examine its influence on patient survival. Multivariate models were based on step-wise addition. RESULTS: Serum sMICA levels were significantly higher in NSCLC patients than in healthy controls (mean +/- SD [pg/ml], 143.52 +/- 27.6 vs. 32.4 +/- 7.53 p < 0.01) and were significantly correlated with TNM stage, poorer differentiation, lymph node metastases and distant metastases. Survival analysis showed that a low sMICA level had longer survival time than those with high serum sMICA. Multivariate analyses indicated that high sMICA proved to be an independent predictor of survival time. CONCLUSIONS: Serum sMICA level in NSCLC patients is associated with metastasis. It is an indicator of a poorer survival probability. Serum sMICA levels may be an independent prognostic factor for NSCLC.