27 September 2013

An important step has been taken towards creating a genomic atlas of cancer

Cancer was sorted by genes

Polina Rozentsvet, <url>Cancer has hundreds of different forms depending on the organs and tissues where it originated, and the genetic changes that cause the development of the tumor and affect the outcome of treatment.

Therefore, treatment that is effective in one case turns out to be useless in another. But if we identify all the mutations that have occurred in the genomes of cancer cells of all types, and all the changes caused by these mutations, and then analyze their relationship with the course of the disease; if we find molecular markers that would allow us to classify cancer cells and, possibly, select treatment in accordance with this classification, we would make significant progress in therapy cancer.

Such an ambitious goal was set by the creators of the Pan-Cancer Initiative project, launched in October 2012. Work on the project is underway as part of the creation of the cancer Genome Atlas – The Cancer Genome Atlas (TCGA), which was worked on by specialists from the National Cancer Institute and the National Institute for Human Genome Research. The results of the first stage of the work are presented in 18 articles, four of which are published in the journal Nature Genetics (Focus on TCGA Pan-Cancer Analysis).

The study required the coordinated work of several dozen scientific groups. Scientists analyzed the data of several thousand patients with 12 types of tumors: glioblastoma multiforme, lymphoblastic acute myeloid leukemia, squamous cell carcinoma of the head and neck, lung adenocarcinoma, squamous cell lung cancer, breast cancer, kidney, cervix, ovaries, bladder and endometrium, colon and rectum adenocarcinoma. In these tumors, all mutations, gene replication and the activity of their work, the metabolic pathways in which each gene participates, the degree of DNA methylation, microRNA and protein synthesis, and the clinical picture of the disease were taken into account. Then they combined all the data and tried to find a connection between them.

Figure from the article in Nature Genetics The Cancer Genome Atlas Pan-Cancer analysis project – VMSuch a large-scale analysis allowed us to look at the genome of a cancer cell from a "bird's eye view", cover the whole picture as a whole and see patterns previously unnoticed.

For example, new rare mutations that determine the occurrence of cancer. These include, in particular, mutations in the genes responsible for packing the DNA molecule into the chromosome (the activity of the genes depends on this).

Malignant tumors are traditionally divided according to their place of origin — for example, lung, skin or intestinal cancer. Molecular analysis has shown that "tissue kinship" does indeed leave a common imprint on cancer cells, but tumors from the same organ or tissue often differ, and tumors of different organs may have common molecular markers.

Thus, the same mutation is characteristic of some glioblastomas and tumors of the stomach, serous membrane of the endometrium, bladder and lungs. Therefore, a drug that is effective for lung cancer may also be suitable for a bladder tumor with the same molecular marker. And breast duct cancer is a group of diseases that are controlled by different genes. Sometimes the same genetic defect causes different consequences depending on the organ where it is found. Thus, the NOTCH gene family, inactive in some tumors of the lungs, head and neck, skin and cervix, is activated in leukemia.

Now scientists are continuing their work, trying to collect as much information as possible. They are investigating new types of tumors, as well as using data obtained from other genome research projects. The global goal of this cancer "combing" is to identify biomarkers that can be used to classify tumors and determine which treatment is most appropriate for each type.

Experts also hope to find targets for the action of new drugs. But that's a long way off. Data still needs to be collected and collected, analyzed and analyzed. There is a long list of questions to answer. For example, which specific mutations and in which tissues cause different risk factors (smoking, inflammation, infection). Hypotheses proposed by researchers based on the analysis will have to be checked in the clinic. The scientists themselves regard the result as the first step on a long journey and are full of optimism.

Portal "Eternal youth" http://vechnayamolodost.ru27.09.2013

Found a typo? Select it and press ctrl + enter Print version