When we took into account of exon length of genes, immunoglobulin genes and mitochondrially encoded genes such as IGHV2-70, IGHD2-15, IGHD3-3, IGLC2, MT-CYB, IGHV1-69-2, IGHG2, and MT-CO3 were potentially having higher mutation burden in a pan-cancer context (Supplementary Data S1). This evidence concerns the gene IGHG2 and cancer.