The 100/D5 antibody is highly specific to Bcl-2 antibody (alpha) and shows no cross-reactivity with Bcl-x or Bax protein. Bcl-2 (b-cell lymphoma #2) is a proto-oncogene located at 18q21.3. Expression of Bcl-2 alpha oncoprotein has been shown to inhibit apoptosis. In most follicular lymphomas, neoplastic germinal centers express high levels of Bcl-2 protein, whereas the normal or hyperplastic germinal centers are negative. Various B- and T-cell lymphoproliferative diseases and some diffuse large B-cell lymphomas are Bcl-2 positive while Burkitt’s lymphoma/leukemia is generally negative.