According to an article published in the New England Journal of Medicine, a malignant tumor has several types of genes . Therefore, a simple biopsy of a tumor can not assure the clinician that the treatment works for the entire tumor. This explains the failure of many cancer treatments.
The researchers made this discovery during several studies on renal tumors. Scientists have investigated the genome of a tumor by taking pieces from different regions of the same tumors and compared samples taken from four different parts of the tumor and metastatic tumors found in other organs. Surprisingly, two thirds of the genes identified were not the same.
Lead author Professor Charles Swanton of the UCL Cancer Institute and Cancer Research UK’s London Research Institute, points out that this is the first time a genome of a tumor is successfully sequenced. He added that the next step is the discovery of drugs that limit the range by controlling the underlying tumor mutations.
Malignant tumor develops as a result of uncontrolled proliferation of a group of cells that have the ability to invade other tissues of the body, either by invasion or by metastasis. This uncontrolled growth is due to abnormalities occurring in the DNA of a cell. There are several causes of these abnormalities, such as inserting viruses in DNA structure, for example Epstein Barr, or the occurrence of spontaneous mutations.
It is very important to apply a differential treatment as the primary tumor may be genetically different from metastatic spread of tumors in the rest of the body. In the study, the scientists found 118 different mutations, 40 of them were found in all biopsies, 53 were found only in some biopsies and 25 were found in one biopsy. This finding is extremely valuable in fighting cancer because it allows researchers to focus treatment on common mutations found in all biopsy samples. Targeting the treatment on the cells responsible for growth is the way to success in combating cancer. That explains why primary tumor removal increases patient survival by preventing relapse.
Dr Lesley Walker, Cancer Research UK’s director of cancer information, stresses the idea that it is very important to implement in the health system this new method of investigating tumors, namely genetic analysis. By sequencing the genome of a tumor clinicians can use a personalized treatment and hopes of success are much higher. He added that plans to replicate the findings in a larger group of patients as part of Cancer Research UK’s Genomics Initiative.