Insertion mutations in exon 20 of the epidermal growth factor receptor gene (EGFR exon20ins) are rare, heterogeneous alterations observed in non-small cell lung cancer (NSCLC). With a few exceptions, they are associated with primary resistance to established EGFR tyrosine kinase inhibitors (TKIs). As patients carrying EGFR exon20ins may be eligible for treatment with novel therapeutics—the bispecific antibody amivantamab, the TKI mobocertinib, or potential future innovations—they need to be identified reliably in clinical practice for which quality-based routine genetic testing is crucial. Spearheaded by the German Quality Assurance Initiative Pathology two international proficiency tests were run, assessing the performance of 104 participating institutes detecting EGFR exon20ins in tissue and/or plasma samples. EGFR exon20ins were most reliably identified using next-generation sequencing (NGS). Interestingly, success rates of institutes using commercially available mutation-/allele-specific quantitative (q)PCR were below 30% for tissue samples and 0% for plasma samples. Most of these mutation-/allele-specific (q)PCR assays are not designed to detect the whole spectrum of EGFR exon20ins mutations leading to false negative results. These data suggest that NGS is a suitable method to detect EGFR exon20ins in various types of patient samples and is superior to the detection spectrum of commercially available assays.
Supplementary Figure 1. Flowchart of high throughout screen (3D HTesiRNAS) in 3D PDAC organoids. Supplementary Figure 2. β8 integrin expression in cell fractions. Supplementary Figure 3. β8 integrin knockdown also radiosensitizes 2D PDAC cell cultures. Supplementary Figure 4. Co-immunofluorescence staining of β8 integrin with GM130, mitotracker, αV integrin, APPL2 and Caveolin. Supplementary Figure 5. Impact of αV integrin expression on survival of patients with PDAC. Supplementary Figure 6. Cytotoxicity of Gemcitabine, chloroquine, colchicine and paclitaxel in BxPC cells. Supplementary Figure 7. β8 integrin and LC3B double staining upon β8 integrin knockdown. Supplementary Table 1. Data of high-throughput esiRNA knockdown screen of 117 focal adhesion proteins in 3D PDAC cell culture. RLUC was the control. Supplementary Table 2. Classification of proteins of the β8 integrin interactome based on raw data of sequential immunoprecipitation-mass spectrometry using PANTHER database
