CASP3 and nasopharyngeal carcinoma: In agreement with the aforementioned in vitro results, IHC of the KLHDC4 knockout xenograft biopsies showed a substantial increase in the number of cleaved caspase-3 and cleaved PARP-positive cells and decreased Ki-67 positive cells (Fig 5D), further supporting the role of KLHDC4 in promoting NPC progression through regulating apoptosis.