Umeå universitets logga

Background: Smoking is by far the most important cause of lung cancer. However, lung cancer among never-smokers is common and increasing [1]. A smoking-independent subgroup of lung adenocarcinoma with certain molecular and clinical features exists [2-3]. Therefore, as 1st project within the Swedish Molecular Initiative against Lung cancer (SMIL) we aim to characterize never-smoking lung cancer for etiological, diagnostic and therapeutic purposes.

Method: Through the Swedish National Lung Cancer Registry [1], we identified all individuals who underwent surgery for lung cancer in Sweden 2005-2014 and who were registered as never-smokers (n=540). At each study site (n=6), clinical data were reviewed by a thoracic oncologist/pulmonologist through patients' medical charts and archived tumor tissues were retrieved and reviewed by a thoracic pathologist. For subsequent studies, we extracted DNA and RNA (using the Qiagen AllPrep kit for FFPE tissue) and constructed tissue microarrays. As a first pre-planned analysis, we performed fusion gene mapping using an RNA-based NanoString nCounter Elements assay, as previously described [4].

Result: In the first 212 (out of 540) analyzed samples, we detected 17 fusions involving ALK, 8 involving RET, and 2 involving NRG1. In addition, MET exon 14 skipping was found in 17 samples. In total, these findings involved 21% of analyzed cases. Additional results from further studies on the cohort will be presented.

Conclusion: SMIL is an ongoing nation-wide molecular research collaboration on lung cancer where we currently collect one of the largest never-smoking lung tumor cohorts worldwide. From the first pre-planned analyses, we conclude that, in a population-based cohort of early stage lung cancer from never-smokers, druggable oncogenic fusions are frequent.