Clinicopathological implications of expressions of hypoxia-related molecules in esophageal superficial squamous cell carcinoma

This study was conducted to clarify whether or not expressions of hypoxia-related molecules would have clinicopathological significance in squamous cell carcinoma (SCC) of the esophagus. Expressions of hypoxia inducible factor-1 alpha (HIF-1α), glucose transporter 1 (GLUT-1) and RAC-1 were immunohistochemically analyzed in 96 surgically resected SCCs at pT1b (sm1, 12 cases; sm2, 35 cases; sm3, 49 cases). They were divided into a lymph node metastasis (LNM)–positive group composed of 44 cases and an LNM-negative group composed of 52 cases. Immunohistochemical profiles were estimated based on the staining extent (score: 1+, 2+, 3+) and intensity (score: 1+, 2+, 3+). A significant expression pattern was found in the nucleus for HIF-1α, cell membrane for GLUT-1 and cytoplasm for RAC-1. The cases were categorized into a high score group (total score of 4 or more) and a low score group (total score of 3 or less) in each maker, respectively. A comparison made between the LNM-positive group and the LNM-negative group showed that the proportion of cases with a high score was larger in the LNM-positive group than in the LNM-negative group (HIF-1α, P = .02; GLUT-1, P = .008; RAC-1, P = .001). Among them, HIF-1α was found to be significantly related to the disease-free survival (P = .019) and overall survival (P = .034) as well as LNM (disease-free survival, P = .030; overall survival, P = .030). The multivariate analysis demonstrated that the HIF-1α expression would be an independent indicator for prognosis. In the superficial SCCs of the esophagus, GLUT-1 and RAC-1 may be involved in LNM, and HIF-1α overexpression is expected to predict an unfavorable clinical outcome.