Here, we report that novel epidermal growth factor receptor (EGFR) gene fusions comprising the N-terminal of EGFR linked to various fusion partners, most commonly RAD51, are recurrent in lung cancer. We describe five patients with metastatic lung cancer whose tumors harbored EGFR fusions, four of whom were treated with EGFR tyrosine kinase inhibitors (TKIs) with documented anti-tumor responses. In vitro, EGFR-RAD51 fusions are oncogenic and can be therapeutically targeted with available EGFR TKIs and therapeutic antibodies. These results support the dependence of EGFR-rearranged tumors on EGFR-mediated signaling and suggest several therapeutic strategies for patients whose tumors harbor this novel alteration.

Cancer molecular heterogeneity might explain the variable response of EGFR mutant lung adenocarcinomas to tyrosine kinase inhibitors (TKIs). We assessed the mutational status of 22 cancer genes by next-generation sequencing (NGS) in poor, intermediate or good responders to first-line gefitinib. Clinical outcome was correlated with Additional Coexisting Mutations (ACMs) and the EGFR Proportion of Mutated Alleles (PMA). Thirteen ACMs were found in 10/17 patients: TP53 (n=6), KRAS (n=2), CTNNB1 (n=2), PIK3CA, SMAD4 and MET (n=1 each). TP53 mutations were exclusive of poor/intermediate responders (66.7% versus 0, p=0.009). Presence of ACMs significantly affected both PFS (median 3.0 versus 12.3 months, p=0.03) and survival (3.6 months versus not reached, p=0.03). TP53 mutation was the strongest negative modifier (median PFS 4.0 versus 14.0 months). Higher EGFR PMA was present in good versus poor/intermediate responders. Median PFS and survival were longer in patients with EGFR PMA ≥0.36 (12.0 versus 4.0 months, p=0.31; not reached versus 18.0 months, p=0.59). Patients with an EGFR PMA ≥0.36 and no ACMs fared significantly better (p=0.03), with a trend towards increased survival (p=0.06). Our exploratory data suggest that a quantitative (PMA) and qualitative (ACMs) molecular heterogeneity assessment using NGS might be useful for a better selection of patients.

No abstract

ATF2 is a transcription factor involved in stress and DNA damage. A correlation between ATF2 JNK-mediated activation and resistance to damaging agents has already been reported. The purpose of the present study was to investigate whether ATF2 may have a role in acquired resistance to cisplatin in non-small cell lung cancer (NSCLC). mRNA and protein analysis on matched cancer and corresponding normal tissues from surgically resected NSCLC have been performed. Furthermore, in NSCLC cell lines, ATF2 expression levels were evaluated and correlated to platinum (CDDP) resistance. Celastrol-mediated ATF2/cJUN activity was measured. High expression levels of both ATF2 transcript and proteins were observed in lung cancer specimens (p << 0.01, Log 2 (FC) 5 14.7). CDDP-resistant NSCLC cell lines expressed high levels of ATF2 protein. By contrast, Celastrol-mediated ATF2/cJUN functional inhibition restored the response to CDDP. Moreover, ATF2 protein activation correlates with worse outcome in advanced CDDP-treated patients. For the first time, it has been shown NSCLC ATF2 upregulation at both mRNA/protein levels in NSCLC. In addition, we reported that in NSCLC cell lines a correlation between ATF2 protein expression and CDDP resistance occurs. Altogether, our results indicate a potential increase in CDDP sensitivity, on Celastrolmediated ATF2/cJUN inhibition. These data suggest a possible involvement of ATF2 in NSCLC CDDP-resistance.Non-small cell lung cancer (NSCLC) is characterized by high incidence and mortality rate worldwide, being the most common subtypes represented by adenocarcinoma and squamous cell carcinoma. 1 Platinum-based chemotherapy in combination with other cytotoxic agents such as Gemcitabine, taxanes and vinorelbine represented the standard of care for unselected patients with advanced NSCLC. Recently, in nonsquamous histology, the combination of cisplatin (CDDP) and pemetrexed showed superior activity. 2,3 However, in chemotherapy-treated NSCLC, the duration of response is relatively short due to primary or acquired resistance to chemotherapy. 4 Patients with advanced disease may not derive any benefit from first-line chemotherapy, while they face significant treatment-related side effects. Consequently, it appears a logical approach to investigate alternative ways to increase the effectiveness outcomes of chemotherapy, through the identification of molecular features suggestive of a better therapeutic ratio.Activating transcription factor 2 (ATF2) is a member of the basic helix-loop-helix (b-ZIP) transcription factor family, whose transcriptional activities are mediated by stressactivated kinases JNK/p38 and activated by phosphorylation on threonine residues. 5,6 Independent of its transcriptional activity, ATF2 also plays an important role in the DNA damage response and in the regulation of intra-S-phase checkpoint (reviewed in Ref. 7). Several studies reported a correlation between ATF2/JNK-mediated activation and resistance to DNA damaging agents. Hayakawa et al. showed that stable expression of ATF...