library_construction_protocol: Genomic DNA was extracted from EDTA-whole blood using QIAamp DNA Mini kit (Qiagen, cat.no. 51304) according to the manufacturer's instructions. Libraries were prepared as outlined in the methods section. Briefly, DNA was bisulfite converted, and five DNA fragments, representing promoter regions of five established tumour suppressor genes, were amplified using custom set of primers (MLH1, chr3:36993123-36993500; CDKN2A, chr9:21974554-21974921; MGMT, chr10:129467118-129467477; CDH1, chr16:68737102-68737469; BRCA1, chr17:43125171-43125550), indexed, and sequenced on the Illumina MiSeq following the manufacturer's protocols.