Immunohistochemical study of MRP5 expression in meningiomas

Serum TIMP1 and TIMP2 concentration in patients with different grades of meningioma

OBJECTIVE

Meningiomas are common primary brain tumors that constitute about 13% of all intracranial tumors. Matrix metalloproteinase-9 (MMP-9) is able to degrade the extracellular matrix and basement membrane leading to cancer cell invasion and metastasis. MMPs are specifically inhibited by a family of small extracellular proteins known as the tissue inhibitors of metalloproteinases (TIMPs). The objective of this project was to evaluate serum concentration of TIMP-1 and TIMP-2 in patients with different grades of meningioma.

PATIENTS AND METHODS

Ninety samples from different stages of patients with meningitis (42 cases of grade I, 28 grade II, 20 grade III) and 51 samples from normal healthy were included in this study. Total protein concentration (TPC) and the level TIMP-1 and TIMP-2 serum were determined by Bio-Rad protein assay based on the Bradford dye procedure and enzyme-linked immunosorbent assay (ELISA), respectively.

RESULTS

No significant change in the TPC was seen in the serum of patients with meningioma when compared with normal controls. Results obtained demonstrated that all serum samples presented TIMP-1 and TIMP-2 expression, whereas, starting from grade I to III meningiomas, a significant decrease of TIMP-1 and TIMP-2 expression was observed as compared to controls.

CONCLUSION

The results of this study show that a low expression of TIMP1 and TIMP2 is correlated with advanced stages of meningioma. It is also concluded that the detection of serum TIMP1 and TIMP2 may be useful in classifying different grades of meningioma.

Genetic and epigenetic alterations in meningiomas

Meningiomas originate from the arachnoid layer of the meninges and divided histologically into three grades: benign (grade I), atypical (grade II), and malignant meningiomas (grade III). Genetic alterations in grade I meningiomas include frequent deletions of chromosomal locus 22q12 and NF2 gene mutations and uncommon somatic SMARCB1 and SMARCE1gene mutations; In grade II meningiomas, chromosomal losses occur on 1p, 22q, 14q, 18q, 10, and 6q, and gains on 20q, 12q, 15q, 1q, 9q, and 17q; In grade III meningiomas, losses have been recognized on 6q, 10, and 14q and alterations of PTEN, CDKN2A and CDKN2B genes. Epigenetic alterations in meningiomas include hypermethylation of the tumor suppressor genes p73 in grade I meningiomas and TIMP3 GSTP1, MEG3, HOXA6, HOXA9, PENK, WNK2 and UPK3A genes with an increasing frequency according to grade. Abnormal expression of IGF signaling family genes and Wnt signaling pathway is associated with meningioma progression. MiRNA expression profiling of meningiomas show downregulation of miR-29c-3p, miR-200a, miR-145 and miR- 219-5p and upregulation of miR-21 miR-335 and miR-190a levels. In conclusion, extensive genetic and epigenetic alterations exist in meningiomas that may help assessing prognosis. In addition, since miRNA expression may be modified by artificial miRNAs, new effective therapeutic strategies may be developed especially for resistant or high grade meningiomas.