Here are the answers to your questions based on the provided scientific article:

1. **What tool was used for pathway enrichment analysis?**
   - DAVID (Database for Annotation, Visualization and Integrated Discovery)

2. **Was a tool version number provided?**
   - Not described

3. **What gene set library was queried (eg: GO, KEGG, Reactome or other)?**
   - Gene Ontology (GO) and KEGG pathway databases

4. **Was a background gene list defined for pathway enrichment analysis?**
   - Yes, the categories of KEGG Pathways served as background databases.

5. **What statistical test was used for enrichment analysis?**
   - Not described

6. **Was false discovery rate correction used to control the number of false positives in the pathway enrichment analysis?**
   - Not described