Prognostic significance of nm23-H1 expression in esophageal squamous cell carcinoma

Tumor recurrence and metastasis are major causes of treatment failure in esophageal squamous cell carcinoma (ESCC). Recently, nm23, originally considered to be an anti-metastatic gene, has been reported to associate with various roles in different human cancers. We therefore investigated the clinical significance of nm23-H1 expression in ESCC.

Pathological sections were immunohistochemically stained with monoclonal antibody that was specific to nm23-H1. Expression of positive nm23-H1 staining was further confirmed by Western blot and reverse transcription-polymerase chain reaction (RT-PCR). The relationship between nm23-H1 expression and clinicopathological variables was examined by statistical analysis. Except for 11 (7%) surgical morality, the remaining 145 patients entered the prognostic analysis. The cisplatin-based chemotherapy was established for the patients with tumor stages at or beyond IIb, or with tumor recurrence. Survival difference between groups was compared by log rank test.

Immunohistochemically, nm23-H1 expression was detected in 39.3% (57/145) of the pathological sections. It was positively correlated with tumor stage (P = 0.002), evident lymphovascular invasion (P < 0.001) and tumor recurrence (P = 0.02). Survival of nm23-H1 positive group was statistically superior to nm23-H1 negative group (P < 0.0001) By multivariate survival analysis, tumor stage, the number of lymph node metastasis and expression of nm23-H1 were the independent prognostic factors for ESCC patients.

Our study demonstrated that nm23-H1 expression was associated with disease progression in ESCC. However, survival of nm23-H1 positive group was superior to nm23-H1 negative group. This paradoxical result could suppose that nm23-H1 expression might increase cisplatin chemosensitivity and hence improve survival. Screening for nm23-H1 expression in tumor cells may be a potential therapeutic strategy in ESCC patients.