CELF2 and pachyonychia congenita: To further reveal the effect of CELF2 regulating CD44 on PC, CELF2 and CD44 overexpression plasmids were co-transfected into PC cells, and it was observed that even CELF2 overexpression could not rescue the effect of CD44 overexpression on the proliferation, migration and invasion of the pancreatic cancer cells (Additional file 2: Figure S2), these results clearly indicated that CELF2 exerts its effects by modulating the expression of CD44.