Hypoxia-inducible factor-1α expression predicts the response to 5-fluorouracil-based adjuvant chemotherapy in advanced gastric cancer

Hypoxia frequently occurs in various solid tumors, thereby accelerating cancer progression and treatment resistance. Hypoxia-inducible factor-1α (HIF-1α) plays a central role in tumor hypoxia by up-regulating the gene expression related to angiogenesis, cancer invasion and anti-apoptosis. The present study immunohistochemically investigated HIF-1α expression in 63 gastric cancer specimens. Those specimens were obtained from 44 patients that received 5-FU chemotherapy post-operatively whereas the remaining 19 patients did not. The immunostaining pattern of HIF-1α was classified into 3 patterns: diffuse-positive within the tumor (DP), positive at the invasive front of the tumor (FP) and negative (N). Thirty-six of 63 (57.1%) patients exhibited DP, 24 (38.1%) revealed FP and the remaining 3 (4.8%) patients were judged as N. The HIF-1α expression pattern grouped into DP and FP/N correlated with the clinicopathological factors and survival. As a result, the HIF-1α expression did not show a significant correlation with the clinicopathological factors, such as the depth of invasion, lymph node metastasis and tumor stage, nor patient survival in the 63 patients. However, in the 44 patients that underwent chemotherapy, patients with the FP/N pattern showed longer survival than those with the DP pattern. On the other hand, no significant difference in survival was found between the 2 patterns among 19 patients without the chemotherapy. These results indicated that the diffuse expression of HIF-1α in gastric tumors might lead to drug resistance against adjuvant chemotherapy using 5-FU. In conclusion, the assessment of the HIF-1α expression in the resected tissues might predict the drug response to adjuvant 5-FU chemotherapy in advanced gastric cancer patients.