HepPar-1 expression in primary lung adenocarcinoma.

Abstract

To study a subset of lung adenocarcinomas with aberrant HepPar-1 antigen expression. We performed a clinicopathologic review of 16 cases. Of 241 primary lung adenocarcinomas tested for expression of the HepPar-1 antigen, 16 (6.6%) were positive. The cases occurred in older smokers with an equal sex distribution. Morphologically, these pulmonary adenocarcinomas had an acinar-predominant architecture, and prominent cribriform growth, with HepPar-1-expressing tumor cells being uniformly columnar with abundant bipolar lightly eosinophilic cytoplasm. HepPar-1 was coexpressed with thyroid transcription factor 1 in 94% of cases. No EGFR mutations were identified, while 31% of cases were positive for KRAS codon 12 mutations. Although aberrant HepPar-1 expression was frequently seen in tumors with visceral pleural and angiolymphatic invasion, its prognostic significance is uncertain.