Detection of novel paraja ring finger 2‐fer tyrosine kinase mRNA chimeras is associated with poor postoperative prognosis in non‐small cell lung cancer

Previously, we reported that the overexpression of fer tyrosine kinase ( FER ), a non‐receptor tyrosine kinase, is correlated with poor postoperative prognosis and cancer‐cell survival in non‐small cell lung cancer ( NSCLC ). In the present study, we further analyzed FER ‐overexpressed NSCLC cases and identified various patterns of chimeric mRNA s, composed of paraja ring finger 2 ( PJA 2) and FER . We detected no genomic rearrangements between PJA 2 and FER and attributed these chimeric mRNA s to alterations at the transcriptome level: i.e., trans ‐splicing. Several chimeric patterns were detected concurrently in each patient, and the pattern sets varied among patients, although the pattern in which PJA 2 exon 1 was fused to FER exon 3 (designated as P e1‐ F e3 mRNA ) was detected constantly. Therefore, in a wide screening for PJA 2‐ FER mRNA s in NSCLC , we focused on this chimeric pattern as a representative chimera. In analyses of 167 NSCLC samples, P e1‐ F e3 mRNA was identified in about 10% of the patients, and the presence of chimeric mRNA was significantly correlated with a high expression level of parental FER mRNA . Furthermore, we found that the detection of P e1‐ F e3 mRNA was correlated with poor postoperative survival periods in NSCLC , consistent with a previous finding in which FER overexpression was correlated with poor postoperative prognosis in NSCLC . This report is the first to suggest a correlation between chimeric mRNA and the expression level of parental mRNA . Furthermore, our findings may be clinically beneficial, suggesting that PJA 2‐ FER mRNA s might serve as a novel prognostic biomarker in NSCLC .