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3082 Background: Identification of “agnostic” genetic drivers in cancer is foreseen as a major step forward in precision medicine.Unfortunately, “off label” use of targeted therapies is not widely available and many oncogenic alteration do not present the same behaviour accross all tumor types.We aimed to analyze the real impact on patients management of the implementation of a systematic screening of genetic alterations in centers of the Spanish Group for Rare Cancer (GETHI). Methods: We designed an observational, prospective and multicenter study to molecularly characterize any adult patient with advanced cancer.Formalin fixed paraffin-embedded samples were studied by TrkA-C,ROS1 and ALK immunohistochemistry followed by RT-PCR when positive to confirm gene fusions. Additonally, the Next Generation Sequencing paltform ArcherFusion Plex (able to detect point mutations and rearrangements in 53 cancer related genes) was implemented.Clinical data regarding treatment administered and outcome, were collected from patients identified as harboring drugable alterations. Results: Up to 26 hospitals all over the country got involved in the study. 341 tumoral tissues, representing 41 different histologies were collected. Molecular studies could be performed in 292 samples that led to the identification of 33 patients as harboring somatic oncogenic mutations. 21 were considered druggable and 5 got targeted therapy directed against the alteration identified (three glioblastoma patients with EGFR mutations received erlotinib, one prostate cancer with a BRAF fusion received trametinib and one lung cancer with ALK translocation, previously deemed as negative by standard screening, received crizotinib). One of the glioblastoma patients achieved a long lasting stabilitation and both the prostate and lung tumors presented dramatic partial responses. Conclusions: Though only few cases harboring drugable alteratons got specif treatment, 50% achieved a meanignful benefit. A wide access to molecular screening and targeted drugs could improve the outcome of cancer patients.