Neuroendocrine lung structures and tumours, immunohistochemical study by specific markers

Out of 360 lungs or lobes surgically removed, 13 non neoplastic specimens and 16 neuroendocrine (NE) tumours are investigated with immunohistochemical methods, in order to evaluate the presence of NE structures in normal and pathological human lungs. The markedused are neuron specific enolase (NSE), chromogranin (CG) and the 80 kd antigen (80 kdAg) of NE secretory granules detected by the new monoclonal Phe-5 antibody. In nonneoplastic lung specimens, clearcut immunoreactivity for al1 three markers appears in NE cells, neuroepithelial bodies (NEB), NE cell-hyperplasias and dysplasias. In the same specimens 4 tumourlets with analogous clearcut immunoreactivities were also observed. The NE tumours show distinct immunoreactivity for al1 three antisera in the 8 well differentiated cases. The 8 poorly differentiated tumours are variably immunoreactive for NSE and present low to ni1 staining with antisera to CG and 80 kdAg. The immunohistochemical data are interpreted according to current views about a possible relationship between NE tumours and parent normal NE lung structures.