부산대학교 도서관

10562 Background: The insulin-like growth factor 1 receptor (IGF1r) is a tyrosine kinase receptor that plays a key role in the growth of normal tissues. The aberration of IGF system has been found in many cancers. Some interesting results about IGF1r were published on GISTs. However, until now the real role on the pathogenesis of this disease and its clinical implications still needs to be defined.Methods: We studied IGF1r in 8 patients affected by gastric GIST. Seven patients underwent surgery at diagnosis, whereas one patient was operated after imatinib and sunitinib treatment. Two patients were young (< 30 years old), and other patients ranged between 54 and 85 years. IGF1r was studied as gene expression profiling performed with Affymetrix GeneChip HG-U133 Plus 2.0 arrays, as genomic copy number with SNP array analysis Affymetrix Genome Wide Human SNP 6.0 arrays, and with western blotting (WB) usinganti-IGF-IRβ (Santa Cruz Biotechnology).Results: The unsupervised analysis of gene expression profiling of our patients merged with a data set from a gastric GIST identified two groups with different regulation of IGF1r (FDR threshold to 0.2%). In particular, IGF1r was up-regulated in the two youngest patients (28 and 30 years-old). The SNPs array analysis gene copy number showed that none of the patients bore IGF1r amplification. The quantitative analysis of protein level by WB again showed that only the two youngest patients had an over-expression of IGF1r. In all the other patients the WB analysis was negative.Conclusions: These results suggest that IGF1r seems to be a novel signalling pathway other than KIT and PDGFRA in a subset of GISTs. The young adult patients had a strongly different molecular background in comparison to the other older ones. The correlation between IGF1r and mutational status of KIT and PDGFRA, clinical outcome, treatments responsiveness as well as its role as potential target deserves to be further investigated. No significant financial relationships to disclose.