NO PREDICTION OF RECURRENCE OF MENINGIOMAS BY PCNA AND KI-67 IMMUNOHISTOCHEMISTRY

Immunohistochemistry for the expression of the proliferation markers p roliferating cell nuclear antigen (PCNA) and Ki-67 was studied in 16 n on recurring meningiomas, 11 meningiomas recurring as benign tumors, 6 recurring as atypical meningiomas and in 9 recurring as malignant men ingiomas. Non recurring meningiomas were defined in this study as tumo rs without recurrence at least 8 years after surgery. In addition 16 b enign recurrences, 14 atypical- and 12 malignant meningiomas were stud ied. In each group great variation of labeling indices (LI) = per cent of tumor cells labeled was observed, especially of PCNA LIs. The non recurring meningiomas displayed lower mean LI for PCNA and Ki-67 than did the recurring meningiomas of all groups but the differences were n ot statistically significant. The same pattern was seen when totally r esected tumors were studied alone. Benign-, atypical-, and malignant m eningiomas had labeling indices that were related to the grade of mali gnancy. Only PCNA LIs of atypical- and malignant meningiomas were stat istically significantly higher than PCNA LIs of non recurring meningio mas. The study indicates that PCNA and Ki-67 are of minor value as pre dictors of recurrence of benign meningiomas.