Recently, multiple genomic researches have mentioned the huge convolution of the cancer genome. Genomic profiling applying microarray technology could layer the tumors into homogeneous subtype, offering new clinical visions for the progress of detections and treatments also systematic reviews on the underlying procedures of tumor development. Furthermore to the microarray technologies, eruptive progresses on sequencing technologies have been made newly, which is entitled NGS. This technology utilized massively parallel sequencing procedure generating hundreds of millions of short (nearly 200bp) DNA reads which can sequence a human genome quickly with much lower expense. This could be recovered by restricting a paired-end sequencing procedure, permitting significant progresses in identifying not only point mutations but as well as genomic rearrangements, such as deletions, amplifications, inversions, translocations, and gene-fusions (95, 96).
Familial Genetic Testing
Genetic analysis for high permeability familial malignancy genes, such as BRCA1, BRCA2, APC and the mismatch repair genes to name a few, is presented to persons presumed to be at high risk arising from their family and clinical history. The beginning of NGS should render to considerable expense savings through concurrent sequencing of numerous goals and numerous specimens. One instant and positive effect of decreased expense sequencing for genetic analysis is that subjects with diseases similar to breast and ovarian cancer, who don’t assemble the present accurate criteria for advice genetic analysis, may become qualified for selection, since a main factor in indicating the restriction of such instructions is the expense of genetic analysis and accessible references. It has been descript that about 30–50% of subjects with a mutation will not have a considerable family history to decision testing (97, 98). Thus, these subjects would only be examination if other more local instructions are utilized like young age of initiation or triple negative breast tumour pathology. These groups are presumably to profit from a more easily accessible NGS method. There is an analogous status in high-degree serous ovarian cancer in that roughly 50% of women with serous ovarian cancer who had a BRCA1 or BRCA2 mutation did not have a considerable family history (99). In addition, lower frequency genes not commonly analyzed but involved in familial cancer syndromes could be contained in standard genetic screen if disease risks could be ascribed to mutations in such genes. The choice criteria for analysing could then be based on whether types within a special gene can be utilized to increase risk approximation given by the clinic to the patient instead of resource restrictions. An additional positive impact would presumably be a decrease in the time period for genetic analysis from months to weeks while simultaneous enhancing the probable throughput for testing. This would enhance the usefulness of BRCA1 and BRCA2 assessing in the background of enrolment in trials open to bearers of BRCA1 or BRCA2 mutations like Poly (ADP ribose) polymerase (PARP) inhibitor trials and as a assistance to surgical management decisions (100). There have been multiple recent papers explaining the utilization of NGS for the goal of familial cancer genetic screening (101-104). A first study by Morgan et al. utilized LRPCR to reinforce and then sequence among all exons of BRCA1, BRCA2 and TP53 in a series of cell lines and patient samples (101). Rather small goal size enabled merger of samples for sequencing on a single lane of an Illumina Genome Analyzer (IIx) stream cell. They discovered that all known pathogenic types could be revealed, containing deletions up to16 bp, with zero false positives utilizing both the commercial software NextGene (SoftGenetics) or custom developed software for analysis .A second study by Walsh et al. utilized a hybridization capture procedure to sequence 21 genes known to be associated with aptitude to breast and ovarian cancer (104).
NGS has been applied in malignancies genomics investigation and changed to be useful in clinical analysis. Moreover, it should be constantly hold in intelligence that although description of structural changes in the malignant genomes by NGS will supply significant portion of knowledge, epigenetic alteration, role of tumor microenvironment and germ-line genetic variation will also have to be obtain into account to have the full feature of the disease.