Galanin and galanin receptor expression in neuroblastic tumours: correlation with their differentiation status

Neuroblastoma and its benign differentiated counterpart, ganglioneuroma, are paediatric neuroblastic tumours arising in the sympathetic nervous system. Their broad spectrum of clinical virulence is mainly related to heterogeneous biologic background and tumour differentiation. Neuroblastic tumours synthesize various neuropeptides acting as neuromodulators. Previous studies suggested that galanin plays a role in sympathetic tissue where it could be involved in differentiation and development. We investigated the expression and distribution of galanin and its three known receptors (Gal-R1, Gal-R2, Gal-R3) in 19 samples of neuroblastic tumours tissue by immunohistochemistry, in situ hybridization and fluorescent-ligand binding. This study provides clear evidence for galanin and galanin receptor expression in human neuroblastic tumours. The messengers coding for galanin, Gal-R1 and -R3 were highly expressed in neuroblastoma and their amount dramatically decreased in ganglioneuroma. In contrast, Gal-R2 levels remained unchanged. Double labelling studies showed that galanin was mainly co-expressed with its receptors whatever the differentiation stage. In neuroblastic tumours, galanin might promote cell-survival or counteract neuronal differentiation through the different signalling pathways mediated by galanin receptors. Finally, our results suggest that galanin influences neuroblastoma growth and development as an autocrine/paracrine modulator. These findings suggest potential critical implications for galanin in neuroblastic tumours development

Malignant peripheral nerve sheath tumors are t(X;18)-negative sarcomas. Molecular analysis of 25 cases occurring in neurofibromatosis type 1 patients, using two different RT-PCR-based methods of detection

To verify the absence of the synovial sarcoma translocation t(X;18) (SYT-SSX) in malignant peripheral nerve sheath tumors, 34 tumor samples from 25 neurofibromatosis type 1 patients were examined in two independent laboratories (Bordeaux, France, and Lausanne, Switzerland) using reverse transcriptase polymerase chain reaction (RT-PCR)-based techniques. RNA was extracted from paraffin blocks using standard methods, reverse transcribed, and conventional (in one laboratory) versus real-time (in the other laboratory) PCR performed. Twenty-seven tumor samples from 19 patients were negative for the t(X;18) in both laboratories; six additional tumors that were t(X;18)-negative in one laboratory gave noninterpretable results in the other, due to lack of internal positive controls; one case was noninterpretable in both places. In conclusion, malignant peripheral nerve sheath tumors in neurofibromatosis type 1 patients do not bear the synovial sarcoma t(X;18) (SYT-SSX). Laboratories that use PCR-based techniques for diagnostic purposes would benefit from quality assurance program