ITGA4 and cancer: These markers were mapped to the exons of 18 genes and the promoters of 21 genes (Additional file 2: Table S3), among which five of the exon-overlapping genes (NSD1, ELMO1, ITGA4, HOXC13 and ITPKB) and three of the promoter-overlapping genes (ESRRG, MEF2D and PTPRU) were curated as cancer genes by the Network of Cancer Genes (NCG) database [22] (Additional file 2: Table S3).