ABSTRACT
Fifty-three primary non-small-cell lung carcinomas (NSCLC) were immunohistochemically investigated with antibodies against chromogranin A, chromogranin B, and ecretoneurin. All 3 peptides were focally immunolocalized in 3 of 25 adenocarcinomas and in 2 of 6 large-cell anaplastic carcinomas in more than 20% of tumor cells. Two of 15 squamous-cell carcinomas showed chromogranin B reactivity in more than 20% of tumor cells. Neuroendocrine (NE) differentiation was also demonstrated in lymphnode metastases of large-cell anaplastic carcinomas, in 1 adenocarcinoma, and in 1 squamous-cell carcinoma, with NE differentiation of the respective primary tumors. All tumors with NE differentiation exhibited (large cell) anaplastic tumor areas. We conclude that NE differentiation should be immunohistochemically proven or excluded, particularly in NSCLC with anaplastic components. Chromogranin B and secretoneurin are proposed as useful additional neuroendocrine markers for demonstration of NE differentiation in lung carcinomas.