Personal approach
Genome-wide sequencing of cancer tumor DNA promises success in the fight against metastases
Specialists of the Vancouver Prostate Cancer Research Center (Vancouver Prostate Centre) suggest that a genetic study of the material obtained from the patient's blood will help doctors to get the right idea about a malignant tumor and choose the best treatment strategy.
Article about technology (Herberts et al., Deep whole-genome ctDNA chronology of treatment-resistant prostate cancer)
published in the journal Nature (fully available by paid subscription), a brief overview can be read on the website of the University of British Columbia.
The idea is to study in more detail than previously done, the DNA that metastatic cancer throws into the bloodstream (known as circulating tumor DNA — ctDNA). By sequencing the genome of this ctDNA completely, it is possible to obtain the information necessary for effective personalized treatment.
The researchers examined ctDNA samples collected from patients with metastatic prostate cancer. Metastatic cancer — cancer that has already spread in the body — is often untreatable. Biopsies, which are supposed to help choose the best treatment methods for this type of cancer, are not performed too often — this is an invasive, painful procedure with a high risk of complications.
Genome-wide ctDNA sequencing provides a lot of information about metastases spreading in the body. Using newly developed computer programs, the researchers were able to pinpoint the unique genetic makeup of various cancer populations in the body to gain a more complete understanding of the disease.
"Metastatic cancers are complex and our understanding of them is limited," says Alexander Wyatt, one of the study's authors. "While traditional biopsies provide only a small slice of the disease, the new test is able to paint a more complete picture of metastases that have spread throughout the body, and all this thanks to a simple and easy—to-perform blood test."
"Every cancer is unique, and every patient responds differently to treatment,— says Dr. Wyatt. "This new generation of ctDNA tests can help doctors choose the treatment option that is most likely to benefit the patient."
Although the number of cancer therapy options has increased in recent years, but often the method showing certain positive results stops working at some point. Cancer resistance to therapy can develop over time, as cancer cells accumulate molecular changes that make them less sensitive to a particular drug or treatment.
Rapid reproduction and various mutations (often a doubling of the whole genome) of cancer cells lead to the emergence of several populations of cells that differ markedly genetically from each other. Treatment becomes a selection factor — the most stable population gains an advantage and continues to multiply.
The work of Dr. Wyatt and his colleagues sheds light on the details of the development of this resistance. ctDNA samples collected over some time have helped to show how cancer develops in response to treatment. The results revealed previously unknown genetic mechanisms of resistance to the most common drugs for the treatment of metastatic prostate cancer.
"This technology can be applied to other cancers to understand how these tumors metastasize and how they ultimately avoid treatment," notes Dr. Wyatt. "It will also help us develop the next generation of cancer treatments that are more effective in addressing resistant diseases."
The researchers believe that their technology is almost perfect — it is minimally invasive, relatively inexpensive and scalable. And it is already being used in major clinical trials conducted by the Vancouver Prostate Cancer Research Center.
Portal "Eternal youth" http://vechnayamolodost.ru