CD56,Chromogranin A and Synaptophysin expression in small cell lung carcinoma and their diagnostic values

Objective To investigate the expression of neural cell adhesion molecule(NCAM/CD56),chromogranin A(CgA) and synaptophysin(Syn) in small cell lung carcinoma(SCLC) and to assess their diagnostic value. Methods 125 SCLC cases had been collected from the archive of the Department of Pathology in PLA General Hospital during the last 4 years(both surgical specimens and biopsies were included).All cases were stained for CD56,CgA and Syn by Max-Vision immunohistochemical technique.The data were analyzed by Chi-square test. Results 90.4%(113/125)of SCLC cases were stained positively for CD56.Generally,the stain was diffuse and most cases(65/125) were moderately to intensely.56.8%(71/125)of the cases showed weakly and focally positive for CgA.The positive percentage for Syn was 82.4%(103/125).The reaction was diffuse and weak in most cases(89/125) with a small proportion of them being focally stained.The positive percentages for CD56 and Syn were insignificantly different(P0.05),but both of them were significantly higher than that of CgA(P0.05). Conclusion As auxiliary molecular markers for the diagnosis of SCLC,CD56 and Syn,showing a positive stain in most SCLC cases,are confirmed to be reliable neuroendocrine markers.With its stable expression in SCLC,CD56 was proved to be the optimal molecular marker for the confirmation of SCLC.