[The use of monoclonal antibodies that recognize the neural cell adhesion molecule (NCAM) in the diagnosis of bone marrow localization of small cell lung cancer].

We have used immunocytochemistry to identify tumor cells in bone-marrow aspirates of 40 untreated patients with small cell lung cancer and we compared the results with conventional histomorphology. The monoclonal antibodies (MAbs) used were NCC-LU-243 and NCC-LU-246 (both cluster 1). For each MAb 76 slides were evaluated. Sixty bone-marrow biopsies were also obtained from these patients. The positivity rate between the 2 MAbs was not statistically different (46% for NCC-LU-246 and 43% for NCC-LU-243). Bone-marrow biopsies detected tumor localization in 8/60 specimens (13%), significantly less than immunocytochemistry with anti-NCAM MAbs (p = 0.003). Moreover, bone-marrow aspirates were positive for cluster 1 antigen in 6/16 patients with limited disease at diagnosis. The results confirm that NCC-LU-243 and NCC-LU-246 have equivalent ability to identify bone-marrow involvement; immunocytochemistry appears to be better suited for this purpose than conventional bone-marrow biopsy; a non-negligible proportion of patients with "limited disease" might be understaged; the clinical value of detecting bone marrow involvement by immunocytochemistry is still unclear.