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An international team has sequenced the entire DNA and RNA of the 61-year-old woman with metastatic adenocarcinoma of the lung, the findings of which are published in the `Journal of Thoracic Oncology`.
The patient never smoked and her lung cancer had entered her bloodstream and spread to other parts of her body. She was treated with several types of chemotherapy.
In fact, the study used Whole Genome Sequencing (WGS), also called Next-Generation Sequencing (NGS), to look at all 3 billion chemical bases of the patient`s normal, as well as the patient`s tumour DNA.
The scientists further examined the normal and tumour RNA for whole transcriptome sequencing, which can reveal the possible defects in how proteins are synthesised. And, this provided an even more intricate view of the tumours biological make up and what might have led to her cancer, says the team.
A review of well-characterised cancer-related genes found that a mutation resided in the TP53 gene, a mutation in the tumour (one base change in the genetic code), and that the mutation was always present in both the DNA and RNA. Such a mutation can halt the creation of tumour suppressor genes and result in the generation of a tumour.
Interestingly, the cancer specimen showed no loss of heterozygosity (LOH), in which one side of DNA`s chromosome becomes inactive because of a mutation.
"This observation highlights the complexity of cancer and how different genetic mechanisms can alter a gene. This novel finding would not have been readily determined without the combined DNA and RNA integration approach," said Dr David Craig of The Translational Genomics Research Institute, one of the authors of the study.
The scientists said these investigative techniques will be used more often to pinpoint the origins of disease.
"In the future, with improved infrastructure and decreased costs, we anticipate that using NGS techniques will become more commonplace. NGS has potential to identify unique tumour aberrations at unprecedented depth," they said.
