Sequential
paraffin sections of 222 epithelial lung
tumors comprising all common histologic types, and 31 pleural
mesotheliomas of all variants were immunostained with
monoclonal antibodies (Mabs)
B72.3 and CSLEX-1. Reactivity with Mabs
B72.3 and CSLEX-1 respectively was noted in 7/57 and 4/57
squamous carcinomas, in 44/70 and 60/70
adenocarcinomas, 9/16 and 11/16
bronchioloalveolar carcinomas, 8/25 and 14/25 large cell
undifferentiated carcinomas, 3/3 and 3/3
adenosquamous carcinomas, 0/11 and 0/11
carcinoids, 0/10 and 2/10 well differentiated neuroendocrine (NE)
carcinomas, 4/13 and 5/13 intermediate cell NE
carcinomas, 0/17 and 0/17 small cell NE
carcinomas, and 0/31 and 1/31
mesotheliomas. In most instances, both Mabs stained the same
tumors; however, reactivity with CSLEX-1 was more intense and extensive, and involved more cases. Therefore, regardless of conventional histologic type, staining with Mabs
B72.3 and CSLEX-1 defines 4 subsets of lung
tumors: one expressing both
antigens, two expressing one but not the other, and one expressing neither. The possible
biological and/or clinical significance of these subsets remains undetermined. When correlated with conventional histologic
tumor types, our findings indicate: 1). both of these Mabs recognize most but not all
adenocarcinomas and
bronchioloalveolar carcinomas, and since CSLEX-1 stained more cases than
B72.3, it may be argued that the former is a broader exocrine phenotype marker than the latter; 2). both of these Mabs select exocrine subsets of large cell
undifferentiated carcinomas; 3). both of these Mabs
stain exocrine cell subpopulations in well differentiated and intermediate cell NE
carcinomas but not in
carcinoids or small cell NE
carcinomas, and 4). except for rare cases, neither
B72.3 nor CSLEX-1 reacts with
mesotheliomas regardless of variant.(ABSTRACT TRUNCATED AT 250 WORDS)