Stereotactic radiosurgical treatment of brain metastases to the choroid plexus.

PURPOSE: Choroid plexus metastases (CPM) are uncommon lesions. Consequently, optimal management of CPM is uncertain. We summarize our experience with stereotactic radiosurgery (SRS) of CPM. METHODS AND MATERIALS: Sixteen consecutive patients with presumed CPM treated with SRS between 1997 and 2007 were examined. Twelve were men with a median age at diagnosis of CPM of 61.9 ± 9.9 years; 14 had metastases from renal cell carcinoma (RCC). All patients had controlled primary disease at the time of treatment for CPM. Four patients with RCC and 1 with non-small-cell lung cancer had undergone whole-brain radiotherapy (WBRT) previously and 2 had received SRS to other brain metastases. The disease-free interval from the primary diagnosis to CPM diagnosis averaged 39.3 ± 46.2 months (range, 1.0-156.3). Five patients were asymptomatic; of the remaining 11, none had symptoms related to CPM. All presented with a single CPM. RESULTS: Average maximum diameter of the CPMs was 2.0 ± 1.0 cm (range, 0.9-4.1 cm); mean volume was 2.4 ± 2.6 cm(3) (range, 0.2-9.3). Median SRS dose was 24 Gy to the 53% isodose line (range, 14-24 Gy). Survival after SRS to the CPM was 25.3 ± 23.4 months (range, 3.2-101.6). Patients in Recursive Partitioning Analysis (RPA) class I (n = 10) had improved survival compared to those in class II (n = 6), as did those with better GPA scores. There were no local failures. After SRS, 1 patient underwent WBRT, 3 patients had one, and another had two subsequent SRS treatments to other brain lesions. Of the 14 patients who have died, 11 succumbed to systemic disease progression, 2 to progressive, multifocal central nervous system disease, and 1 to systemic disease with concurrent, stable central nervous system disease. There were no complications related to SRS. CONCLUSIONS: Most CPMs are associated with RCC. SRS represents a safe and viable treatment option as primary modality for these metastases, with excellent outcomes.

The Aurora A F31I polymorphism is not a risk factor for glioblastoma.

BACKGROUND: The Aurora A F31I polymorphism has been linked to increased risk of several human cancers. Glioblastoma (GBM) is the most malignant glioma as well as the most frequent adult primary brain tumor. METHODS: In this case-control study we investigated the association of Aurora A F31I polymorphism with GBM risk. RESULTS: A total of 96 histologically confirmed patients with GBM and 93 health individuals were analyzed for the Aurora A F31I single nucleotide polymorphism. The single nucleotide polymorphism data were compared and risks associated with individual genotypes and allelotypes were evaluated in terms of odd ratios. CONCLUSIONS: The data obtained from this case-control study demonstrates that the Aurora A F31I polymorphism is not a significant risk for GBMs.

The role of a single nucleotide polymorphism of MDM2 in glioblastoma multiforme.

OBJECT: Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, with a 5-year survival rate of < 5%. Aberrant function of TP53 is common in GBM. Although mutational inactivation of p53 is found in many cases, there remain tumors in which genetic alterations of p53 are absent. Negative regulators of the TP53 pathway such as MDM2, which directly inhibits TP53 expression and activity, may influence the pathogenesis of GBM. To understand its potential function in gliomagenesis, the authors analyzed a novel single nucleotide polymorphism (SNP) in the MDM2 promoter that enhances MDM2 expression. METHODS: The investigators isolated DNA from 98 patients with GBM and 102 healthy, cancer-free controls. A polymerase chain reaction analysis was performed to determine the MDM2 SNP309 genotype by using distinct primer pairs for the wild-type (T) and mutant (G) alleles. RESULTS: The frequency of the mutant MDM2 polymorphism was found to be higher (p = 0.0092) in patients with GBM (54.6%) compared with healthy controls (41.2%); the TT and GG genotypes were more common in healthy controls and patients with GBM (p = 0.0004 and p = 0.02, respectively). Although there was no association between the MDM2 SNP309 and overall survival, the GG genotype was associated with development of GBM at a younger age in patients with tumors harboring wild-type p53, which may mitigate the effect of the MDM2 SNP. CONCLUSIONS: Although the MDM2 SNP309 does not portend decreased survival, the increased incidence of the mutant G allele in patients with GBM and its influence on age of onset suggest a potential role in the molecular pathogenesis of GBM, and may be a therapeutic target.

Aurora B expression correlates with aggressive behaviour in glioblastoma multiforme.

Chromosomal abnormalities and genomic instability are common features of, and possible driving forces in, tumorigenesis. Recently, several mitotic proteins that are critical to proper chromosome segregation have been identified. Members of the Aurora kinase family have been identified as having important roles in mitosis; overexpression induces multicellularity and fosters polyploidy. As aneuploidy is a common feature of malignant gliomas, particularly glioblastomas (GBMs), we examined 25 prospectively collected GBMs to assess the role that overexpression of one member of this family, Aurora B, might have in the clinical behaviour of GBMs. Aurora B expression levels were markedly correlated with a shortened survival. Aurora B expression was not directly related to age, tumour proliferation status or to several common molecular changes found in GBMs. These results suggest that Aurora B may be a prognostic feature of impaired survival and a novel therapeutic target in some patients.

A novel method to detect functional microRNA targets.

MicroRNA (miRNA) molecules are non-coding RNAs, 19 to 24 nt in length that have been identified recently as important regulators of gene expression. Several computational methods have been developed to describe the target recognition mechanism by miRNA. We propose here a novel method to detect miRNA-mRNA complexes in eukaryotic cells. As a first step, we synthesize cDNA on an mRNA template using miRNAs as the endogenous cytoplasmic primer. This step extends miRNA and overcomes the problem of low complementary binding of miRNAs to their targets. Purified hybrid 3'-cDNA-miRNA-5' molecules are used in a second round of reverse transcription to anneal to target mRNA in a highly gene-specific manner. The 5'-end analysis of these cDNA molecules demonstrated that primers for cDNAs were "signatures" of miRNA molecules, and over-expression of their full-length mature miRNAs resulted in functional inhibition of target protein expression.