Detection of small-cell-lung-cancer cells in bone-marrow aspirates by monoclonal antibodies NCC-LU-243, NCC-LU-246 and MLuC1.

We have used immunocytochemistry to identify tumor cells in bone-marrow aspirates of patients with small-cell lung cancer and we have compared the results with conventional histomorphology. The monoclonal antibodies (MAbs) used were NCC-LU-243 and NCC-LU-246 (cluster 1) and MLuC1 (cluster 6); 108 slides (52 patients) incubated with NCC-LU-246, 106 (51 patients) with NCC-LU-243 and 69 with MLuC1 (36 patients) were evaluated. Bone-marrow biopsies (83) were also obtained from 50 of these patients; 48/108 bone marrow aspirates were positive for cluster-1 antigen and 22/69 were positive for MLuC1. Immunocytochemistry with anti-NCAM MAbs detected bone-marrow localization in 38/83 bone-marrow aspirates compared with 9/83 bone-marrow biopsies, while MLuC1 was positive in 18/60 and bone-marrow biopsies in 6/60. Moreover, bone-marrow aspirates were positive for cluster-1 antigen in 7/17 patients with limited disease at diagnosis. Patients with positive bone-marrow biopsies had significantly shorter survival. No differences were found between patients with positive and those with negative marrow aspirates.