Overexpression of CD40 in sacral chordomas and its correlation with low tumor recurrence
To determine the degree of CD40 overexpression in sacral chordomas and its correlation with tumor recurrence. CD40 or CD31 overexpression was determined by immunohistochemical staining; the microvessel density (MVD) was calculated according to the CD31 expression. The correlation of CD40 over-expression with tumor recurrence was analyzed. 56% of the specimens from 36 cases of sacral chordomas overexpressed CD40, which is a significantly higher percentage than for the 2 specimens in 10 in normal notochordal tissue (p < 0.05). 36.84% of the specimens of the 19 recurrent cases were CD40 overexpressing, in contrast to less than 76.47% in the no-recurrence group (p < 0.05). Multivariate analysis demonstrated that CD40 overexpression and the resection margins were independent factors contributing to tumor recurrence. The MVD value was 25.71 ± 8.86 mm(-2) in the sacral chordomas and more than 6.63 ± 2.45 mm(-2) in the normal embryonic notochord tissue (p < 0.01). The MVD value in the recurrence group (30.08 ± 7.11 mm(-2)) was significantly higher than that of the no-recurrence group (20.82 ± 8.18 mm(-2); p < 0.05). But the MVD value was significantly lower in the CD40-overexpressing group than in the CD40-less expressing group (p < 0.05). CD40 was overexpressed in sacral chordomas, and the overexpression was not dependent on the intratumoral MVD. CD40 overexpression was correlated with low recurrence of the tumor, implying that CD40 plays an important role in the antitumor response against sacral chordomas and in the inhibition of tumor recurrence.