Expression of SPARC in tongue carcinoma of stage II is associated with poor prognosis: an immunohistochemical study of 86 cases.

SPARC (secretory protein acidic and rich in cysteine), also known as osteonectin or BM-40, associates with progression in various kinds of tumors. We have examined whether SPARC expression can be a prognostic marker for patients with head and neck squamous cell carcinomas (HN-SCC). We examined immunolocalization of SPARC in 86 clinical specimens of tongue carcinoma. Although there was no correlation between SPARC positivity in the tumor cells and tumor stages, the 5-year overall survival rate was significantly lower in the SPARC positive cases (28.6%) than in the SPARC negative cases (91.7%), confined to stage II patients (p < 0.001, Wilcoxon test). Additionally, in stage II cases (n = 3), frequency of the postoperative metastasis was significantly higher in SPARC positive cases (5/8, 62.5%) than in the negative cases (1/15, 6.7%) (p < 0.01, chi2 test). Together with these results, SPARC can be a beneficial prognostic marker for the stage II tongue carcinoma, of which clinical outcomes are sometimes difficult to predict.