To provide and develop the most appropriate genetic therapy for one's cancer, personalized oncogenomics has been developed. By sequencing a cancer patient's genome, a clinical scientist can better understand which genes/part of the genome have been mutated specifically in that patient and a personalized treatment plan can potentially be implemented. With the advent of next-generation sequencing, the genome-wide sequencing analyses have been made more accessible to thoroughly understand the genetics of each patient's cancer. Genetic material from tumour biopsies can be analyzed by two genome-wide approaches: whole exome sequencing (WES) and whole genome sequencing (WGS). By developing tools to analyze these extensive sequence data, scientists have begun to comprehend how diseases, including cancer, can be attributed by genes and intergenic variants such as single nucleotide polymorphisms (SNPs) and copy number variants (CNVs). Although more expensive than WES, whole genome sequencing allows clinical scientists to understand how cancer can be caused by alterations in a genome including single nucleotide variants (SNVs), SNPs and CNVs. Since WES samples only the exome (the collection of known coding regions of the genome) alterations in the non-coding region of the genome will not be detected by WES. Non-coding regions, including untranslated regions, introns, promoters, regulatory elements, non-coding functional RNA, repetitive regions, and mitochondrial genomes, make up 98% of the human genome, the function of most regions remains unexplored. Although these methods are useful in finding shorter variants, they are limited by read lengths of sequencing technology and are unable to detect large indels and structural variants. Though variants in a non-coding region are not uncovered by WES, both approaches identify all mutations that are known to cause cancer in a given patient and have been helpful in identifying low frequency and rare pathogenic (disease-causing) variants. However, the challenge remains in analyzing all the genetic variations in a genome for the clinical significance (whether a mutation is disease-causing as not all mutations are harmful) as much of the genome is not thoroughly understood, and new variants are still being discovered. To better understand the pathogenicity of all possible genomic variants to interpret WES/WGS data, researchers are systematically studying genome-wide sequencing data across many tumour genomes. Whole exome sequencing has been the conventional data used by international cancer genome research programs such as The Cancer Genome Atlas (TCGA) and The International Cancer Genome Consortium (ICGC).