Treatment with S-1–cisplatin is established as a standard first-line treatment of patients with unresectable metastatic gastric cancer in Japan. However, the useful biomarker to predict patients' response to this treatment remains unclear. We investigated the clinicopathologcal factors related to the response to S-1–cisplatin treatment in patients with unresectable metastatic gastric cancer. Moreover, we examined whether REG Iα, an antiapoptotic factor, could be a useful biomarker to predict the response to chemotherapy in these patients.Patients and methods
Seventy patients with stage IV-gastric cancer received first-line chemotherapy with S-1–cisplatin. We investigated the relationship between clinicopathological factors and duration of progression-free survival. REG Iα expression was immunohistochemically evaluated using biopsy samples before chemotherapy, and its relationship to clinicopathological factors was also investigated.Results
The median progression-free survival (PFS) of all patients was 5.4 months. In patients with scirrhous type of gastric cancer, PFS tended to be shorter than that in patients with non-scirrhous type of gastric cancer (P = 0.058). Of the 70 gastric cancer tissues, 19 (27%) were positive for REG Iα protein. Univariate and multivariate analyses revealed that REG Iα expression was independently predictive of worse progression-free survival [hazard ration (HR) 4.00; P < 0.0001]. None of patients with REG Iα-positive gastric cancer responded to chemotherapy.Conclusion
REG Iα may be a reliable biomarker to predict the poor response to chemotherapy with S-1–cisplatin in patients with metastatic gastric cancer.