RESUMEN
Integrins are heterodimeric transmembrane glycoproteins resulting from the non-covalent association of an α and ß chain. The major integrin receptor for collagen/laminin, α2ß1 is expressed on a wide variety of cell types and plays an essential role in the adhesion of normal and tumor cells to the extracellular matrix. Integrin-triggered signaling pathways promote the invasion and survival of glioma cells by modifying the brain microenvironment. In this study, we investigated the association of a specific genetic polymorphism of integrin α2ß1 with the incidence of diffusely infiltrating astrocytoma and the progression of these tumors. Single-nucleotide polymorphism in intron 7 of the integrin ITGA2 gene was examined in 158 patients and 162 controls using polymerase chain reaction and restriction enzyme analysis. The ITGA2 genotype +/+ (with a BglII restriction site in both alleles) exhibited higher frequency in grade II astrocytoma compared to control (P = 0.02) whereas the genotype -/- (lacking the BglII site) correlated with the poorest survival rate (P = 0.04). In addition, in silico analyses of ITGA2 expression from low-grade gliomas (LGG, n = 515) and glioblastomas (GBM, n = 159) indicated that the higher expression of ITGA2 in LGG was associated with poor overall survival (P < 0.0001). However, the distribution of integrin ITGA2 BglII genotypes (+/+, +/-, -/-) was not significantly different between astrocytoma subgroups III and IV (P = 0.65, 0.24 and 0.33; 0.29, 0.48, 0.25, respectively) compared to control. These results suggest a narrow association between the presence of this SNP and indicate that further studies with larger samples are warranted to analyze the relation between tumor grade and overall survival, highlighting the importance of determining these polymorphisms for prognosis of astrocytomas.
RESUMEN
In this paper, the authors present the case of a patient with multifocal intradural extramedullary ependymoma, and they review 18 previously reported cases. A 32-year-old man presented to the authors' institution with a 1-month history of partial medullary syndrome. Magnetic resonance imaging of the neuraxis revealed multifocal intradural extramedullary lesions at the bulbomedullary junction and C2-3, T5-11, L-2, L-4, L-5, and sacrum. Histological examination revealed a WHO Grade II ependymoma. The literature survey yielded 18 cases of ependymoma at the same location; none of them were multifocal at presentation. The authors analyzed the epidemiological, clinical, and surgical features of all 19 cases reported to date, including the present case. Patients' ages ranged from 24 to 69 years; 15 patients were women and 4 were men. The time elapsed from symptom onset to diagnosis ranged from 1 month to 8 years. Pain (in 13 patients) and medullary syndrome (in 12) were reported as the initial symptoms (information was not provided for 1 patient). Tumors were predominantly located in the thoracic spine (11), but they also occurred in the cervicothoracic (3), cervical (2), and lumbar (2) spine. The remaining tumor was multifocal. Solitary extramedullary tumors were found intraoperatively in 13 patients; 3 were described as exophytic and 3 as extramedullary with some degree of medullary invasion. Histological examination revealed 9 WHO Grade II tumors, 4 Grade III tumors, and 1 myxopapillary tumor. Data obtained for the remaining cases proved inconclusive. The clinical condition improved in 11 patients, remained stable in 2, and worsened (recurrence or progression) in 6. Of the 4 patients with Grade II tumors who presented with recurrence or neuraxis spreading, 3 had meningeal infiltration or adhesion to the pia mater, which does not rule out the possibility of neoplastic remnants in that area. Intradural extramedullary ependymomas are rare, they predominate in women in the 5th decade of life, and pain is the most frequent initial symptom. The extent of resection and the presence of meningeal infiltration seem to be key determinants of prognosis. The present case is the first intradural extramedullary ependymoma (with the exception of those occurring at the conus medullaris and terminal filum) with multiple lesions at presentation.