Analysis of expression of microRNAs and genes involved in the control of key signaling mechanisms that support or inhibit development of brain tumors of different grades.

BACKGROUND: MicroRNAs (miRNAs) are a class of small non-coding RNA molecules involved in the regulation of key biological processes. Different miRNAs with pro-oncogenic and anti-oncogenic properties have been identified in glioblastomas. We decided to analyze expression profiles of 10 mature miRNAs (miR-7-1, miR-10а, miR-17, miR-20а, miR-21, miR-23а, miR-26а, miR-137, and miR-222) in post-surgery glioma specimens of different grades in order to find whether the expression level correlates with tumor grades. We also measured expression of six key genes such as PTEN, p21/CDKN1A, MDR1, ABCG2, BAX, and BCL-2 involved in the regulation of critical glioma signaling pathways to establish the effect of miRNAs on these signaling mechanisms. METHODS: Using RT-PCR, we performed expression analysis of 25 tumor fresh samples (grades II-IV). RESULTS: We found gradual increase in miR-21 and miR-23a levels in all tumor grades whereas miR-7 and miR-137 were significantly down-regulated depending on the glioma grade. MDR, ABCG2, and p21/CDKN1A levels were significantly up-regulated while expression of PTEN was down-regulated in tumor samples compared to the normal brain tissue. CONCLUSIONS: These observations provide new insights into molecular pathogenic mechanisms of glioma progression and suggest about a potential value of miRNAs as a putative diagnostic marker of brain tumors.

Lipomas of the pineal region.

BACKGROUND: Intracranial lipomas are rare lesions, representing 0.02% of operated intracranial lesions. Lipomas of the pineal region are even rarer and are reported occasionally in the literature. This is possibly because of the fact that they may give rise to clinical symptoms rather infrequently. When they become symptomatic, some form of management must be contemplated. METHODS: Four cases of lipomas of the pineal region observed in our institute during a 5-year period were investigated, and clinical-diagnostic features were studied. Two of the cases were symptomatic and were submitted to direct surgical treatment. RESULTS: Computed tomography (CT) scanning was performed in 3 cases and magnetic resonance imaging (MRI) in all 4. MRI angiography was performed in the last case. The appearance of the lipoma was quite pathognomonic in the neuroimaging diagnostic test. The infiltrative character of the lesion was better defined by MRI. MRI angiography gave evidence of the upward displacement of the deep veins. Direct surgical approach was performed via a right occipital transtentorial approach in one case and supracerebellar route in another. Neither approach appeared to be superior to the other one. Total removal of the lesion seemed to be impossible because of the infiltrative character of the lesion. Postoperative results were satisfactory even with incomplete removal of the lesion. CONCLUSION: Lipomas of the pineal region are rare. Modern neuroimaging permits a straightforward diagnosis of the nature of intracranial lipomas in general and of these lipomas in particular. Some form of management must be contemplated when these lesions become symptomatic. Direct surgical approach, either via an occipital transtentorial or an infratentorial supracerebellar approach, is feasible. Tumor removal must be dealt with cautiously because total removal is impossible without unacceptable postoperative deficits, and generous partial removal warrants long-term symptomatic improvement.