Representative immunoperoxidase with anti–Bcl-2 and anti-Bax antisera. (A) anti–Bcl-2 study of lymphoma negative for Bcl-2 (arrowhead indicates positive staining in background small lymphocyte); (B) same case as (A) showing positive staining in greater than 20% of lymphoma cells with anti-Bax antisera; (C) anti–Bcl-2 study of lymphoma showing Bcl-2 positivity in fewer than 20% of the neoplastic cells (arrowheads indicate positive large atypical cells); (D) same as (C) showing positive staining in greater than 20% of lymphoma cells with anti-Bax antisera; (E) anti–Bcl-2 study of lymphoma showing Bcl-2 positivity in greater than 20% of the neoplastic cells; (F) same case as (E) showing lymphoma with greater than 20% of cells positive for Bax.