Does protein expression predict recurrence of benign World Health Organization grade I meningioma?

The aim of this study was to assess the predictive value of recurrence of protein expression in surgical samples of meningiomas. Thus, the expression of proteins that have been reported to be associated with prognosis of meningiomas was assessed in a sample of 59 World Health Organization grade I tumors obtained after Simpson grade I to III surgical resection (complete excision) and that were followed for 6 to 16 years. The expression was investigated applying immunohistochemical and tissue microarray techniques. One protein, the hepatocytic growth factor receptor, of 22 investigated proteins, showed significantly differing expression when comparing the 38 nonrecurrent with the 21 recurrent World Health Organization grade I meningiomas. It is noteworthy however that by means of logistic regression analyses, the independent predictive value of this protein expression was not significantly associated with the recurrence. Furthermore, it is noteworthy that the proliferation rate estimated by means of Ki67 expression did not show a significant difference, being 3.3 +/- 0.4 for the nonrecurrent meningioma and 3.9 +/- 0.5 for the recurrent and ranging from 0% to 10%. A significant and differing Spearman rank order of correlation was noted between 19 pairs of the investigated proteins when comparing nonrecurrent with recurrent World Health Organization grade I meningiomas. None of these correlations, however, showed a significant association by means of logistic regression analyses. Our results indicate that the Simpson grade significantly alters the outcome of a World Health Organization I grade meningioma and a longer follow-up period significantly increases the risk of recurrence. The expression of none of the proteins or correlation between protein expressions previously reported to be of significance regarding recurrence can be recommended as a diagnostic tool while assessing the risk of recurrence of World Health Organization grade I meningiomas.