ABCG2 and pachyonychia congenita: The ABC transporter-mediated anticancer drug efflux is a common mechanism of chemoresistance (Trigueros-Motos et al., 2017), and Yang C et al. discovered that ABCA8 expression was significantly increased in human pancreatic cancer (PC) cells after gemcitabine (GEM) treatment and in GEM-resistant (Gem-R) PC cells.