p53 and epidermal growth factor receptor (EGFR) are common genes involved in the pathogenesis of lung cancer, but their roles in lymphoepithelioma-like carcinomas (LELC) are unclear. In this study, we investigate the roles of p53 and EGFR in LELC carcinogenesis. Forty-six pulmonary LELCs were identified to evaluate p53 and EGFR aberrations. p53 mutations were identified in three patients, which all occurred in exon 8. EGFR mutations were detected in 8 of 46 cases with a majority of exon 21 mutations but without L858R. The other cases harbored mutations in exons 20 and 18. Only one case gained a deletion in exon 19. Notably, EGFR mutation was more commonly observed in patients with tumor size ≤ 3 cm (P = 0.014). In addition, there was a trend of more common EGFR overexpression in female (22/30) than in male patients (7/16, P = 0.061). However, there was no correlation between p53/EGFR mutations and protein expressions, suggesting the presence of complex mechanisms. p53 and EGFR mutations are uncommon in LELCs, indicating that these genes are not the important events in carcinogenesis for this tumor subtype. The EGFR mutation in 35% patients with LELC tumors <3 cm in size suggests the potential benefits to EGFR tyrosine kinase inhibitors of inoperable LELCs.
© 2010 Japanese Cancer Association.