PARP9 and pachyonychia congenita: And to elucidate the relationship between PARP9, LOXL2, and drug resistance in PC, we initially performed a comparative analysis of multidrug efflux system-associated genes, including ABCB1 (ATP-binding cassette subfamily B member 1), ABCC1 (ATP-binding cassette subfamily C member 1), ABCG1 (ATP-binding cassette subfamily G member 1), and ABCG2 (ATP-binding cassette subfamily G member 2), between normal pancreatic tissues and PC tissues using the GEPIA online database.