Such exon 9 PIK3CA mutations were discussed not to have an independent effect on anti-EGFR efficacy [8] and in all three patients we found the same mutation also in pretreatment samples, i.e. primary tumor (#2 and #5) or metastasis (#8) (Table S1) suggesting that targeted deep sequencing has not contributed to the identification of therapy related changes in the tumor genomes of our patient cohort. This evidence concerns the gene PIK3CA and neoplasm.