Detection of rearrangement of anaplastic lymphoma kinase (ALK) and mutation of epidermal growth factor receptor (EGFR) in primary pulmonary lymphoepithelioma-like carcinoma.

Abstract

BACKGROUND: Primary pulmonary lymphoepithelioma-like carcinoma (LELC) is a distinct rare subtype of lung cancer. The prevalence of anaplastic lymphoma kinase (ALK) rearrangement and epidermal growth factor receptor (EGFR) mutation in primary pulmonary LELC had not been thoroughly investigated. METHODS: We investigated a cohort of 42 patients with primary pulmonary LELC and genotyped for ALK rearrangement and EGFR mutation. ALK rearrangement was detected by fluorescence in situ hybridization (FISH). EGFR mutational analysis of exons 18 through 21 was analyzed by TaqMan real-time polymerase chain reaction (PCR). RESULTS: Epstein-Barr virus-encoded RNAs (EBERs) showed positive signals in all 42 patients. By immunohistochemistry staining, all patients demonstrated positive expression of CK5/6 and P63, but almost all patients were negative for TTF-1 (34/34, 100%) or CK7 (34/35, 97.1%). None of the 42 patients had ALK rearrangement. Of 42 patients tested, only one patient (2.4%) harbored L858R mutation and gefitinib was applied to this case, however no objective response was observed and the progression free survival (PFS) time was only 1 month. CONCLUSIONS: Primary pulmonary LELC is a unique histological subtype of lung cancer. ALK rearrangement and EGFR mutation are lack and they may not be the oncogenic driver gene in pulmonary LELC. Future efforts should be made to explore other oncogenic driver gene to guide targeted therapy in this rare disease to determine the optimal treatment.