nci metathesaurus nci metathesaurus the nci metathesaurus is product of the us national cancer institute's enterprise vocabulary service, a collaborative effort of the nci center for bioinformatics and the nci office of communications. the nci metathesaurus is based on nlm's unified medical language system metathesaurus supplemented with additional cancer-centric vocabulary. the public version of the nci metathesaurus currently contains all public domain vocabularies from the national library of medicine's umls metathesaurus, as well as a growing number of nci-specific vocabularies developed by the national cancer institute. the public version of the nci metathesaurus also contains proprietary vocabularies. certain vocabularies, such as icd-10 and icd-o-3, are made available, by permission, for non-commercial use only. others, specifically meddra, are made available subject to license restrictions.