The nm23-H1 gene as a predictor of sensitivity to chemotherapeutic agents in oesophageal squamous cell carcinoma

Recently, nm23-H1, an anti-metastasis gene, has been reported to correlate with sensitivity to chemotherapeutic agents including cisplatin in human br east and ovarian carcinoma cells. The aim of this study was to evaluate a r ole for nm23-H1 in responsiveness to cisplatin-based chemotherapy in patien ts with oesophageal squamous cell carcinoma (OSCC). The expression of nm23- H1 protein was examined immunohistochemically in 32 eligible patients with OSCC who underwent adjuvant chemotherapy with cisplatin, etoposide, and 5-f luorouracil after tumour resection. Fifteen (46.9%) of 32 patients were pos itive for nm23-H1 staining and 17 (53.1%) were negative. Both disease-free survival and overall survival rates of nm23-H1-negative patients were signi ficantly shorter than in nm23-H1-positive patients (P < 0.01 for both). The re was no significant difference in clinicopathologic characteristics betwe en nm23-H1-positive and nm23-H1-negative groups. Multivariate analysis also showed that nm23-H1 expression was the most significant factor for overall survival of OSCC patients included in this study (P = 0.0007). To further study the role of nm23-H1, a human OSCC cell line (YES-2) was transfected w ith a plasmid containing a fragment of the nm23-H1 cDNA in an antisense ori entation. Reduced expression of nm23-H1 protein in the antisense-transfecte d (AS) clones was found by Western blot analysis as compared to wild-type Y ES-2 and YES-2/Neo (clone transfected with the neomycin resistance gene alo ne). MTT (3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl tetrazolium bromide) assa y showed that reduced expression of the nm23-H1 protein in AS clones was co nsistent with the degree of increased resistance to cisplatin but not etopo side or 5-fluorouracil. These data support the conclusion that reduced expr ession of nm23-H1 may be associated with resistance to cisplatin, suggestin g the value of nm23-H1 expression as a prognostic marker for OSCC patients who are to undergo cisplatin-based chemotherapy (C) 1999 Cancer Research Ca mpaign.