CASP3 and rheumatoid arthritis: To investigate antigen retrieval (AR), we heated archival formalin-fixed paraffin-embedded RA synovial specimen-deparaffinized sections in EDTA solution with pH > 9 (S3307, Antigen Retrieval Reagent, high pH, Dako) for 5 min at 120 °C by autoclaving (heating-AR at high pH), and utilized an extremely sensitive indirect enzyme-labeled antibody method, the horse radish peroxidase (HRP)-labeled and secondary antibody-labeled polymer reagent method (polymer method, ordinary-IHC in Table 1) employing anti-cleaved caspase-3 antibody (Table 1).