> the majority of cancer causing sequence variants are found in non-coding regions of the genome That's not entirely accurate. The majority of variants occurs

> the majority of cancer causing sequence variants are found in non-coding regions of the genome That's not entirely accurate. The majority of variants occurs in the non-coding genome, but that's also because the vast majority of the genome is non-coding. There certainly are non-coding variants that are oncogenic (e.g. hTERT promoter), but for the most part the functional significance of a given non-coding variant is unknown. I'm not suggesting greater sequencing isn't important, but there are a lot of considerations that goes into what part of a cancer genome get sequenced (WGS, exome, gene panels, specific variants). We simply don't know what a lot of the variants do, but for those that suggest a particular therapy (BRAF V600E), it can be quite effective.