Table 2.

Overview of the development of sequencing technologies that have enabled the understanding of the genetic component of cancer development

Methods	Explanation
Cytogenetics	These are methods used to study the structure and function of chromosomes. In cancer, they commonly refer to methods such as karyotyping, fluorescent in situ hybridisation (FISH), and comparative genomic hybridization (CGH), and give an overview of which areas of the chromosome may have been lost or gained during oncogenesis
Polymerase chain reaction (PCR)	The amplification of a few copies of a short region of DNA, generating thousands to millions of copies of this sequence. This allows the detection of mutations within the amplified sequence
Next generation sequencing	Next generation sequencing (NGS), massively parallel or deep sequencing are related terms that describe a DNA sequencing technology that can sequence an entire human genome within a single day. This is a catch-all term used to describe a number of different sequencing technologies such as Illumina (Solexa), Roche 454, Ion torrent or SOLiD sequencing

DNA sequencing technologies allow us to “read” DNA. By comparing the sequence of DNA in cancer compared to normal cells, we can identify changes that might be driving the growth of cancer. Comparisons between patients with cancer and those without may also reveal the presence of inherited mutations