Tissue and serum expression of microRNAs miR-34a, miR-143, miR-145 and miR-335 is not correlated with tumor progression in meningiomas
Meningiomas are the most common primary tumors of the central nervous system, accounting for 35.5% of cases, considering all age groups. Despite progress made in recent decades, tumorigenesis of meningiomas still remains a challenge. There is a consensus of a need for molecular tools to assist in diagnosis and prognosis of meningiomas. In this context, some studies demonstrate the importance of the role of estrogen and progesterone receptors, as well as the understanding of alterations in microRNA (miRNAs) expression levels in the tumorigenesis of meningiomas. The serum expression profile of miRNAs has been shown to correlate with tumor classification and clinical evolution. Investigation of such miRNAs as biomarkers is of great interest because it would be a non-invasive procedure. We evaluated the tissue and serum expression profile of miRNAs associated with estrogen and progesterone receptor pathways in grade I, II and III meningiomas. Tissue and blood samples from 40 patients with grade I, II and III meningiomas were investigated using real-time PCR to analyze the expression of the miRNAs miR-34a, miR-143, miR-145 and miR-335. The miRNAs miR-34a and miR-145 had significantly lower expression in the tumor tissue samples of grade II meningiomas when compared to grades I and III. We did not observe significant differences in miRNA expression in the blood samples. We concluded that the expression of these miRNAs is not correlated with tumor progression in meningiomas.