Detection of active caspase 3 and cleaved PARP-1/p89 in biopsy specimens of primary nodal DLBCL. (A) Staining for active caspase 3 demonstrating brown, mostly nuclear, staining primarily in cells with morphologic features of apoptosis. (B) Cleaved PARP-1/p89 staining demonstrated strictly nuclear staining, also primarily in cells with morphologic features of apoptosis. (C) Double staining for active caspase 3 and CD20. (D) Cleaved PARP-1/p89 and CD20 demonstrating that active caspase 3-positive cells and cleaved PARP-1/p89-positive cells (both brown nuclear staining) are CD20⁺ positive (blue membranous staining) and thus probably neoplastic B cells. (E) Staining for active caspase 8 demonstrating brown, mostly nuclear, staining, also primarily in cells with morphologic features of apoptosis.