Proliferative potentials of intracranial chordomas with a reference to extracranial chordomas

Some intracranial chordomas are known to have frequent recurrence in their clinical course. The biological features regulating recurrence of intracranial chordomas has not been elucidated. We studied the proliferative potentials of chordomas with an immunohistochemical staining method using anti-Ki-67 antibody, MIB-1, together with an immunohistochemical examination on the expression of p53 protein. The correlation among MIB-1 staining indices, the immunoreactivities of p53 protein and clinical courses of intracranial chordomas was analyzed retrospectively, and the statistically significant correlation between MIB-1 staining index (SI) and recurrence has been clarified. The mean MIB-1 SI of recurrent tumors was 10.2%, which was higher than that of non-recurrent tumors (2.8%). The p53 immunopositivity correlated well with recurrence and high MIB-1 SI. Literature review also showed the importance of MIB-1 Sl and p53 overexpression in extracranial chordomas. In conclusion, both the examination on proliferative potentials of chordomas using MIB-1 Sl and the study on the immunoreactivity of p53 protein, are important for their biological and histopathological analyses and the prediction of future recurrence.