Reduced syndecan-I expression is correlated with the histological grade of malignancy at the deep invasive front in oral squamous cell carcinoma

BACKGROUND: Although many histopathological characteristics of oral squamous cell carcinoma (O-SCC) have been identified as prognostic factors, no factor is completely accurate and unequivocal. This study evaluated the association between the loss of syndecan-I expression and the histological grade of malignancy at the deep invasive front in O-SCC. METHODS: The expression of syndecan-I at the invasive tumor front of O-SCC was examined immunohistochemically using archived tissue from 72 cases. The mean age of the patients was 62.5 years (range: 23-90 years) and the male-female ratio was 1.3:1 (41 men, 31 women). There were 26, 24, 11, and I I cases classified as stages I-IV respectively. The correlation between the intensity of syndecan-I immunostaining and the clinicopathological factors, especially the histological grade of malignancy at the deep invasive front (invasive front grade) was analyzed. RESULTS: Of the 72 cases, seven (9.7%), 29 (40.3%). 36 (50.0%) showed strong, intermediate, and weak or negative syndecan-I staining respectively. There were significant differences between syndecan-I expression and prognosis, differentiation, and pattern of invasion at the deep invasive front. Moreover, the invasive front grade scores, based on the intensity of syndecan-I staining, were 5.6 +/- 1.0, 8.0 +/- 2.1, and 10.2 +/- 2.3 points with strong, intermediate, and weak or negative intensity respectively; and the difference was significant (P < 0.0001). Patients with intermediate or strong intensity for syndecan-I had significantly better prognoses than did those with negative or weak intensity (P = 0.0138). CONCLUSION: This study demonstrated that the reduced expression of syndecan-I seems to be a useful marker of histological malignancy at the deep tumor invasive front and may be a useful prognostic factor in O-SCC.