CTRC and cystic fibrosis: We identified seven potential pain modifiers in CF, including chymotrypsin C (CTRC), serine protease inhibitor Kazal-Type 1 (SPINK1), tumour necrosis factor (TNF), ATP-binding cassette subfamily B Member 1 (ABCB1), protease serine 1 (PRSS1) and transforming growth factor beta 1 (TGFB1) interacting with the CFTR gene.