3.7 Remained
Questions
Although the microarray-based genome-wide investigation is effec-
tive and informative, these approaches can’t directly identify chro-
mosomal rearrangements, tumor-specific point mutations, small
insertions/deletions (INDEL), or structure variations (SVs). Rou-
tine diagnostic microarray profiling of DNA CNA in ALL is becom-
ing increasingly widely used, either using oligonucleotide array-
based comparative genomic hybridization or SNP microarrays.
Data from these arrays must be analyzed and interpreted with
great care, as several array platforms, even those with hundreds of
thousands of features, lack sufficient resolution to detect very focal
alterations. Consequently, there is intense interest in the use of
next-generation sequencing technology for comprehensively geno-
mic investigation.4 Next-Generation Sequencing-Based Investigation Era
4.1 Next-Generation
Sequencing
Investigation
Since the completion of the Human Genome Project in 2003
[113, 114], genomic research has stepped into the whole genome
research era. Of note, the onset of next-generation sequencing
(NGS) reduced the cost of whole genome sequencing for one
individual from $500 million to around $14 million [115]. With
a decade of technology improvement, cost of NGS is still dropping
and has only charged $1000 to sequence a human genome in 2016
(Fig.3); $100 could be even expected in the near future. Although
the technologies of sequencing long-read are becoming more
mature, the prevalent applications of NGS are still focusing on the
short-read sequencing which has advanced cost-effective platforms.Fig. 3Cost decrease for sequencing human genome with the development of technologies for genomic
investigation
400 Heng Xu and Yang Shu