CHEK2 and cancer: One study revealed that a daily intraperitoneal administration of high-dose Vit-C (4 g/kg) inhibited the growth of neuroblastoma and ovarian cancer in a xenograft model, with increased checkpoint kinase 2 (CHK2), as well as histone 2AX (H2AX) function in malignancies resulting in DNA damage, which may be an in vivo cancer effect.