Small Cell Lung Cancer and Embryonic Lung Epithelium Share Monoclonal Antibody Defined Neuroendocrine-related Antigens

¹ The Department of Clinical Immunology, University Hospital, Groningen, The Netherlands.

Our results indicate that epithelial cells of first trimester fetal lungs have an antigenic makeup, which is similar to that of SCLC. Both epithelial and NE antigens are present. During fetal development, the NE antigens are lost, for the major part, at the beginning of the second trimester. Only NE cells are still reactive with MOC-1, whereas the NE antigens defined by MOC-21, -32 and -52 disappear completely. Leu-7 is not present on first trimester epithelia, but is expressed in NE cells during the second and third trimesters. Adult lung epithelium does not contain any NE-related antigens, except in occasionally occurring NE cells, which react with MOC-1 and Leu-7. The occurrence of a number of NE antigens in both first trimester fetal lungs and in SCLC suggests that these NE-related antigens in SCLC could represent reexpressed fetal lung antigens.