Clinical Application Of Targeted Next-Generation Sequencing For Lung Cancer Patients: A Belgian Experience

Objective: International efforts to catalogue mutations for multiple forms of cancer coupled with the successes of targeted agents in patients with molecularly defined tumors and improvements in genomic technology have generated enthusiasm for incorporating genomic profiling into clinical cancer practice. Molecular testing represents a paradigm shift in lung cancer diagnosis and has now become a standard of care. International guidelines recommend testing for EGFR mutations to guide patient selection for therapy. However, different biomarkers for which potentially active agents are being evaluated, such as PIK3CA, BRAF or ERBB2 mutations, have been proposed as valuable for managing patients with lung cancer. The increase in the number of genes to test is associated with a decrease in the sample size. The pathologist is facing a new challenge: optimization of available tumor tissue. As the number of clinically significant genetic variants has increased, clinical testing has evolved, moving from single mutations to multiplex hotspot evaluations in multiple cancer genes. Recently, next generation sequencing (NGS) has begun to supplant other technologies for gene panel sequencing that is now required for targeted therapies. In the present study we evaluate the clinical applicability of targeted NGS for patients with lung cancer. Methods: After initial validation of the Ion Torrent AmpliSeq colon/lung cancer panel using commercial reference standards, the panel which interrogates 1850 hotspots in 22 cancer-related genes was prospectively applied to clinical practice. The DNA of 234 samples from 2 different institutions was obtained from formalin-fixed paraffin-embedded material (including 69 surgical specimens, 83 biopsies and 82 cell blocks) and subjected to targeted NGS with the Ion Torrent AmpliSeq colon/lung cancer panel using the Ion Torrent Personal Genome Machine. Results: Our validation study showed that sensitivity and accuracy for detecting variants at an allelic frequency u003e4% was 100% for commercial reference standards. The set of 234 samples included 120 primary tumors and 114 metastatic lesions. 88% of tested samples were adenocarcinomas. For one case only, the sequencing was not performed due to an insufficient quantity of available tissue. Among the 233 cases sequenced, 223 (95.7%) samples were successfully sequenced. The number of mutations per tumor ranged from 0 to 9. The most frequent mutations were found in TP53 (42.1%) and KRAS (35.9%). Of successfully sequenced cases, 57 potentially actionable mutations were identified in 54 patients (24.4%), including 26 EGFR mutations, 8 PIK3CA mutations, 14 BRAF mutations, 3 PTEN mutations, 2 ERBB2 insertions, 2 NRAS mutations and 2 MEK1 mutations. The frequencies of these variants detected by NGS were consistent with frequencies reported in public databases. Conclusions: Overall, the AmpliSeq colon/lung cancer panel can be applied in daily practice even for small samples, such as lung biopsies or cell blocks. Moreover, it provides clinically relevant information for lung cancer patients. Citation Format: Nicky D9Haene, Marie Le Mercier, Nancy De Neve, Oriane Blanchard, Myriam Remmelink, Birgit Weynand, Isabelle Salmon. Clinical application of targeted next-generation sequencing for lung cancer patients: A Belgian experience. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-39.