OLFM4 is associated with lymph node metastasis and poor prognosis in patients with gastric cancer.

The present study investigated the clinical significance of the relationship between olfactomedin 4 (OLFM4) expression and the clinicopathological features of patients with gastric cancer. Tumor tissue and adjacent normal tissue, lymph nodes, and peritoneal metastases were analyzed by the Affymetrix GeneChip(®) HG-U133A2.0 array. The expression of OLFM4 was detected by real-time quantitative RT-PCR in gastric tumor tissue and adjacent normal tissue. OLFM4 expression was analyzed by immunohistochemistry in 436 clinicopathologically characterized gastric cancer cases and in corresponding distant metastases from 61 patients. A total of 434 genes and 169 expressed sequence tags were upregulated, including OLFM4. The expression of OLFM4 mRNA or protein differed significantly among gastric tumor tissue, matched normal gastric mucosa, and lymph node metastases. Further multivariate analysis suggested that lymph node metastases and distant metastases, TNM stage, and expression of OLFM4 were independent prognostic indicators for gastric cancer. Gene expression profiles were useful for simultaneously analyzing the expression levels of thousands of genes. Reduced expression of OLFM4 in gastric cancer is associated significantly with lymph node and distant metastases and with poor prognosis. OLFM4 may prove to be an important molecular marker for predicting the carcinogenesis, development, progression, and metastasis of gastric cancer.