PADI4 and AL amyloidosis: Histone cit has been identified as a biomarker and therapeutic target in cancer, particularly as PAD4-mediated cit of histone H3 is associated with poor clinical outcomes and a high rate of short-term mortality in patients with advanced cancer, and it can also predict the risk of venous thromboembolism.231,233,346 Studies have also indicated that PAD2-mediated cit of histone H3 at arginine 26 promotes malignant progression in multiple myeloma and prostate cancer.223,347 Targeting both PAD4 and HDAC2 concurrently emerges as a promising approach in osteosarcoma therapy.