Expression of CD66 in non-Hodgkin lymphomas and multiple myeloma

⁹⁰Y-labeled anti-CD66b monoclonal antibody clone BW 250/183 was developed for treatment of tumors. The aim of the study was the analysis of CD66 expression in lymphoproliferative malignancies to expand the potential of anti-CD66-based therapy.

Bone marrow samples from 260 patients were examined for the expression of CD66 on tumor cells in 104 B-chronic lymphocytic leukemias (B-CLL), 28 mantle cell lymphomas (MCL), 22 follicular lymphomas (FCL), 15 marginal zone lymphomas (MZL), 12 lymphoplasmacytic lymphomas (LPL), 13 diffuse large B cell lymphomas (DLBCL), 4 T-non-Hodgkin lymphomas (T-NHL), 3 B-NHL not otherwise specified (B-NHL NOS), 3 B acute lymphoblastic leukemias (B-ALL), and in 56 multiple myelomas (MM) by flow cytometry.

Positive (≥ 20%) expression of CD66abce clone Kat4c was detected in 76% of B-CLL and 76.8% of MM. The highest number of CD66abce-positive samples was in MCL and LPL (96.4% of 28 and 91.7% of 12 patients, respectively). Expression of CD66b clone BW 250/183 was examined in 114 of 260 samples. Positive expression was detected in 23.3% of B-CLL (6/35), 17.1% of MM (7/30), and 21.4% of MCL (3/14) samples.

The expression of CD66b compared to CD66abce was lower in all measured samples. Use of radiolabeled anti-CD66b antibody for the treatment of lymphoproliferative diseases appears to have limited preclinical substantiation.