To do this, you can do a POST query with your pathway identifiers to the endpoint described here

To know if a Pathway is a disease, look at  the “isInDisease” property. The disease name is contained in the displayName of the diseases in the “disease” array of the Pathway models.

One query example would be 

 
curl -X 'POST' \ 
    'https://reactome.org/ContentService/data/query/ids' \ 
    -H 'accept: */*' \ 
    -H 'Content-Type: text/plain' \ 
    -d 'R-HSA-9679506,R-HSA-8876384' > pathwaysDescription.json 

To do this for multiple ids using cypher, you can use this query:

 
MATCH (p:Pathway) 
WHERE p.stId in ["R-HSA-9679506","R-HSA-8876384"] 
OPTIONAL MATCH (p)-[:disease]->(d:Disease) 
RETURN p,d 

Using the optional match allows you to get both pathways associated with a disease and those which are not. 

If you want to filter for only disease pathways, use the following:

 
MATCH (p:Pathway)-[:disease]->(d:Disease) 
WHERE p.stId in ["R-HSA-9679506","R-HSA-8876384"] 
RETURN p,d 

You just need to provide your list of stId (reactome identifiers) in the “where” list.

Finally, if you want to export a table instead of viewing it in the browser, use the following:

 
MATCH (p:Pathway) 
WHERE p.stId in ["R-HSA-9679506","R-HSA-8876384"] 
OPTIONAL MATCH (p)-[:disease]->(d:Disease) 
WITH p, collect(d) as diseases 
RETURN p.stId, p.displayName, p.isInDisease, [d in diseases | d.displayName] as diseaseNames, [d in diseases | d.databaseName + ":" + d.identifier] as diseaseIdentifiers 

Note that some pathways, like R-HSA-9608290 are associated with several diseases.