SPARQL query not working - SNOMED-CT ontology

Question

I'm trying to execute a very simple SPARQL query to retrieve information about a specific disease using https://bioportal.bioontology.org/ontologies/SNOMEDCT/?p=classes&conceptid=root (in Java) based on a name passed in the query string, and I don't understand why it's not working. Here are the relevant code:

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

SELECT DISTINCT *
FROM <http://bioportal.bioontology.org/ontologies/SNOMEDCT>
FROM <http://bioportal.bioontology.org/ontologies/globals>
WHERE
{
    ?x rdfs:label ?label .
    FILTER (CONTAINS ( UCASE(str(?label)), "MELANOMA") )
}

Answer 1

The only occurrence of rdfs:label in SNOMED-CT on BioPortal is snomed-term: rdfs:label "SNOMEDCT". BioPortal uses skos:prefLabel (which is a subproperty of rdfs:label) instead.

Try this query:

PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX snomed-term: <http://purl.bioontology.org/ontology/SNOMEDCT/>

SELECT DISTINCT *
FROM <http://bioportal.bioontology.org/ontologies/SNOMEDCT>
FROM <http://bioportal.bioontology.org/ontologies/globals>
WHERE {
    ?x skos:prefLabel ?label .
    FILTER (CONTAINS ( UCASE(str(?label)), "MELANOMA") )
}

There should be 10 results.

If you need to restrict results to diseases, probably you'd have to add ?x rdfs:subClassOf+ snomed-term:64572001 to your query. But unfortunately, it seems that the BioPortal SPARQL endpoint doesn't support SPARQL 1.1 property paths.