Low Transforming Growth Factor-β3 Expression Predicts Tumor Malignancy in Meningiomas

We sought to clarify the expression characteristics and prognostic significance of transforming growth factor (TGF)-β3 in cranial meningiomas.

We analyzed the expression of TGF-β3 at the mRNA level in 38 frozen meningioma samples. Clinical data collection, follow-up, correlations, and survival analyses were performed.

World Health Organization (WHO) grade I meningiomas showed an average expression level of 2.55, which was higher than that of WHO grade II (average of 1.50) and WHO grade III (average of 0.21) (Kruskal-Wallis test, P = 0.008). For meningiomas with a history of surgery, the mean TGF-β3 expression level was 0.71, much lower than that of primary meningiomas with a mean value of 2.55 (Mann-Whitney U-test, P = 0.008). According to the Kaplan-Meier analysis and univariate Cox analysis, WHO grade (P = 0.001), history of surgery (P < 0.001), tumor volume (P = 0.045), preoperative Karnofsky Performance Status (P = 0.001), peritumoral brain edema (P = 0.039), postoperative radiotherapy (P = 0.001), degree of resection (P = 0.039), and TGF-β3 expression (P = 0.038) were prognostic factors for tumor recurrence. In addition, WHO grade (P < 0.001), history of surgery (P < 0.001), preoperative Karnofsky Performance Status (P = 0.002), peritumoral brain edema (P = 0.006), postoperative radiotherapy (P = 0.007), bone invasion (P = 0.03), and TGF-β3 expression (P = 0.041) were prognostic factors for mortality.

TGF-β3 expression levels gradually declined with the increase of WHO grade and were lower in recurrent meningiomas than in primary meningiomas. Besides, low TGF-β3 expression was found to predict tumor recurrence and mortality in meningiomas based on univariate analysis.