MAPK1 and pachyonychia congenita: Interestingly, the results from Gene Ontology enrichment analysis of The Cancer Genome Atlas (TCGA) data showed that high ABCA8 expression in PC was significantly associated with “positive regulation of ERK1 and ERK2 cascade” (Supplementary Fig. S7), indicating that ERK signaling also contributed to the ABCA8-mediated chemoresistance.