Heme oxygenase-1 expression predicts cervical lymph node metastasis of tongue squamous cell carcinomas

Heme oxygenase-1 (HO-1) is known as a stress-inducible protein. The present study was designed to investigate the relationship between HO-1 expression levels and clinical features of tongue cancer by using HO-1 responsiveness to stress as a clinical indicator. One-hundred and twelve biopsy samples from tongue squamous cell carcinomas were analyzed semiquantitatively by immunohistochemistry. Correlations between the expression level of HO-1 and the clinical features of tumors were statistically analyzed. Fifty-four cases with surgical confirmation of lymph node metastasis were examined for the association between cervical lymph node metastasis (pN) and other clinical features, including the HO-1 expression level, using logistic regression. The low HO-1 expression group contained significantly more undifferentiated samples (P=0.04) and pN positive cases (P=0.01) by univariate analysis. The low HO-1 expression group (odds ratio=8.49; 95% confidence interval=1.64-44.09, P=0.01) and an endophytic shape (odds ratio=16.79; 95% confidence interval=1.77-159.53, P=0.01) were significantly associated with an increased risk of developing lymph node metastasis by multivariate analysis. Low HO-1 expression was associated with lymph node metastasis. The expression profile suggests HO-1 could be used clinically as a marker for tumors possessing the potential for lymph node metastasis. This method could prove useful as an adjuvant method to detect lymph node metastasis and may help reduce the number of surgeries by indicating when surgery is unnecessary.