The Neural Cell Adhesion Molecule NCAM is a membrane glycoprotein and belongs to the immunoglobulin superfamily. It is expressed on neural cells as well as on various neuroendocrine tumors and can be detected in sera of patients with small cell lung cancer. Its role is attributed to tumor invasion and formation of metastases. Malignant plasma cells and a subset of plasma cells from patients with monoclonal gammopathy exhibit surface expression of NCAM whereas normal plasma cells do not express NCAM. Expression as measured by flow cytometry using anti-CD56 antibodies does not seem to correlate with clinical course, however leukemic myelomas and myeloma cell lines tend to loose NCAM surface expression. An isoform of NCAM which is rich in polysialic acids and characteristic for embryonal NCAM (eNCAM) has been shown to be elevated in sera of patients with multiple myeloma using a chemiluminescence immunoassay. Patients with progressive myeloma tend to have high serum NCAM levels above the normal range of 20 U/ml. Analysis of 125 myeloma patients suggest that serum NCAM is a valuable parameter for tumor progression rather than tumor mass. Increase in serum NCAM may be associated with loss of adhesive function.

In 59 patients with ductal pancreatic cancer the monoclonal antibody (MAb) BW 494, which detects the CA 494 glycoprotein antigen, was analyzed in comparison with the reference tumor markers CA 19-9 and CEA. Eighty-one patients with non-pancreatic malignancies of the gastrointestinal (GI) tract, 95 with chronic pancreatitis, 124 with benign non-pancreatic GI diseases, 30 with diabetes mellitus (type I or type II) and 114 healthy blood donors served as controls. The sensitivity of pancreatic cancer was 90%, 44% and 90% for CA 19-9, CEA and CA 494, respectively. In chronic pancreatitis, as the most important control population for pancreatic cancer, the specificity was 85%, 72% and 94% for CA 19-9, CEA and CA 494, respectively.

Background. Small cell lung cancer (SCLC) is distinguished from other histologic types of lung cancer by possessing a variety of neuroendocrine properties. Neuron‐specific enolase (NSE) is the most frequently elevated tumor marker for patients with SCLC at diagnosis. To assess the value of neural cell adhesion molecules (NCAM), another possible tumor marker for small cell lung cancer, NCAM was evaluated in the sera of patients with histologically confirmed SCLC in two prospective multicenter trials. Methods. The study includes 221 patients with SCLC, normal human blood donors (n = 34), patients with benign lung disease (n = 53), and patients with non‐small cell lung cancer (n = 28). NCAM was determined by means of an enzyme immunoassay, NSE by a radioimmunoassay. Results. The data show the following: (1) 51% (113 of 221) of all patients with SCLC had NCAM levels higher than 20 U/ml, 34% (75 of 221) had NSE levels higher than 25 ng/ml; (2) levels of both markers significantly differ between limited and extensive disease patients; (3) patients with pathologic NCAM and NSE levels have significantly shorter survival times; (4) a positive correlation between pretreatment NSE and NCAM levels was found (n = 221, r = 0.60); and (5) a correlation between serum marker levels and clinical status was found in follow‐up studies of 19 patients. Conclusions. From these data, it is concluded that NCAM is, along with NSE, a potential tumor marker for SCLC.

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A retrospective study was carried out to determine the diagnostic and prognostic value of the soluble form of the embryonal neural cell adhesion molecule NCAM (CD56) in paraproteinemia. NCAM, beta 2-microglobulin, and interleukin-6 levels were measured in the sera of 170 patients with paraproteinemia. Of these, 125 had multiple myeloma, 20 Waldenström's disease, and 25 monoclonal gammopathy of unknown significance. Serum NCAM proved superior to beta 2-microglobulin and interleukin-6 in distinguishing multiple myeloma from paraproteinemias of various causes, with a high specificity of 95.5% in detecting multiple myeloma, although with a low sensitivity of 40%. In multiple myeloma NCAM is significantly correlated with beta 2-microglobulin, paraproteinemia, and low albumin levels. For the determination of tumor load beta 2-microglobulin levels accord best with the Salmon and Durie classification scheme. When patients are grouped according to their clinical course, the disease development is reflected better by NCAM than by beta 2-microglobulin or interleukin-6. Survival data indicate that all three markers have prognostic potential. Prognostic accuracy with respect to overall survival is best with beta 2-microglobulin.