Lung Lymphoepithelial Carcinoma

Background: This study aimed to evaluate the clinical significance of baseline Epstein-Barr virus (EBV) DNA in recurrent or metastatic primary pulmonary lymphoepithelioma-like carcinoma (PLELC). Methods: 75 patients with baseline EBV DNA were included. The relationships between baseline EBV DNA and clinical characteristics, survival and objective response rate were analyzed. Results: The baseline EBV DNA levels were related to the liver, chest wall, distant lymph node(s) or multiple sites of distant metastasis. The high baseline EBV DNA group (≥41,900 copies/ml) was related to shorter progression-free and overall survival in univariate analysis and remained significant for progression-free survival in multivariate analysis. Conclusion: The baseline EBV DNA is a valuable biomarker for predicting prognosis and reflecting tumor burden in recurrent or metastatic PLELC.

Pulmonary lymphoepithelioma-like carcinoma (PLELC) is a rare form of non-small cell lung carcinoma (NSCLC) that shares similarities with nasopharyngeal carcinoma. The optimal treatment for stage III-N2 PLELC remains controversial.

We conducted a retrospective analysis from stage III-N2 PLELC patients between 2009 and 2022 in our center. The patients were categorized into three groups: Group 1 (G1, definitive chemoradiotherapy), Group 2 (G2, radical surgery plus adjuvant chemoradiotherapy), and Group 3 (G3, radical surgery plus adjuvant chemotherapy).

A total of 103 patients were included in the study, with 34, 25, and 44 patients in G1, G2, and G3, respectively. The median follow-up time was 47.4 months. The overall median PFS was 66.6 months, with 3-year PFS and 3-year OS rates of 66.0% and 92.4%, respectively, for all patients. Multivariate analysis revealed no significant difference in PFS between G1 and G2 (p = 0.354), while both groups exhibited significantly longer PFS than G3 (p < 0.001; p = 0.039). Similarly, no significant difference in OS was observed between G1 and G2 (p = 0.649), but both tended to demonstrate improved OS compared to G3 (p = 0.081; p = 0.092). Only one case of grade 3 radiation esophagitis was observed in G1, and no grade 3 or higher radiation pneumonitis were reported.

Patients with stage III-N2 PLELC have a favorable prognosis, with radiotherapy playing a crucial role in treatment. Both definitive chemoradiotherapy and radical surgery followed by chemoradiotherapy demonstrate favorable efficacy and manageable toxicity.

Pulmonary lymphoepithelioma-like carcinoma (pLELC) is a rare malignancy that lacks specific biomarkers. N6-methyladenosine (m⁶ A) is the most widespread internal modification of messenger RNA (mRNA), and its dysregulation is involved in the development of many cancers. However, the expression of m⁶ A genes in pLELC and their roles are unknown. We obtained an exosomal transcriptome data set of patients diagnosed with pLELC and healthy controls using RNA sequencing and identified differentially expressed genes (DEGs) in the two groups using R software. The differential expression of the 37 m⁶ A genes in the two sets of samples was further analyzed, and receiver operating characteristic (ROC) curves were plotted for each gene to identify their grouping ability. The STRING database was used to construct a protein-protein interaction network for m⁶ A genes. An mRNA-miRNA regulatory network of m⁶ A-related DEGs was constructed using the miRNet database, and a prediction score formula was established. A nomogram was constructed based on the candidate m⁶ A genes and prediction scores. The expression of key genes was determined through the immunohistochemical (IHC) staining of clinical tissue sections. Using ROC curves, nine m⁶ A genes were revealed to have classification efficacy in both groups of samples. We screened seven m⁶ A-related DEGs (MAN2C1, HNRNPCL1, FUS, EIF6, DIP2A, COA3, and BUD13) that were beneficial for grouping and constructed nomogram models. Through IHC, we identified FUS and EIF6 as being possibly involved in the occurrence and development of pLELC. The m⁶ A gene expression patterns in pLELC-derived exosomes were significantly different from those in healthy controls. We screened several key genes to facilitate the development of diagnostic markers for pulmonary lymphoepithelioma.