Abstract
Cancer pathogenesis is a multistep process involving the accumulation of
complex genetic and epigenetic alterations. The disease can be sporadic or familial in
nature. The genes associated with much familial cancer or inherited cancer susceptible
syndrome have already been identified. Thus, genetic testing for pathogenic variants of
these genes could predict whether an individual has a high risk of developing cancer in
their lifetime. Also, tumour DNA sequencing in patients with cancer can be used for
therapy selection and to predict treatment outcomes. The recent development of high
throughput sequencing enables the exploration of whole genome profiling, including
mutations, structural variations, transcriptomes, splicing events, etc., in patients with
cancer, thereby providing guidelines for personalized precision medicine in clinical
practice. However, the translation of cancer genome sequencing information into the
clinical treatment plan is highly complicated, needs multidisciplinary expert panels and
is not cost-effective for mass application. Further development in sequencing analysis
and data interpretation are imperative for point-of-care settings applications. This
chapter outlines the clinical significance of tumour DNA testing and genomic
sequencing in various cancers.