Footnotes

• Contributors EVD and NAS designed the study. MVZ and VMP collected the tumour samples. EVD and TSG performed laser microdissection and whole genome amplification. NAS and SAV performed array comparative genomic hybridisation and analysed data. EVD, NAS and SAV wrote the paper. INL, NVC and VMP assisted in critiquing, editing and refining the paper. All authors reviewed the manuscript.

• Funding The study was supported by the Russian Scientific Foundation (grant #14-15-00318). The study was done using equipment under support of Human Proteome Project of Russian Academy of Sciences. EVD was supported by Tomsk State University Competitiveness Improvement Programme.

• Competing interests None declared.

• Patient consent Obtained.

• Ethics approval The procedures followed in this study were in accordance with the Declaration of Helsinki (1964, amended in 1975 and 1983). This study was approved by the institutional (Cancer Research Institute, SB RAMS) review board, the patient signed an informed consent for voluntary participation, and the number of ethical approval was 10 (29 September 2011).

• Provenance and peer review Not commissioned; externally peer reviewed.

• EVD and NAS contributed equally.