14 December 2016

Lymphocytes against cancer

Maxim Rousseau, Polit.roo

A group of doctors led by Steven A. Rosenberg from the National Cancer Institute reported that the new treatment method they used was able to get rid of cancer in the first patient. I published a scientific article about it The New England Journal of Medicine (Tran et al., T-Cell Transfer Therapy Targeting Mutant KRAS in Cancer), the NIH website briefly reports on the achievement of scientists.

The patient was Celine Ryan, 50, from Michigan, who had colon cancer. There was a mutation in her genome in the gene encoding the KRAS protein. Mutations in this protein are often associated with various oncological diseases. It is most common in patients with pancreatic cancer and colorectal cancer.

The study was associated with lymphocytes penetrating tumor tissues (tumor-infiltrating lymphocytes, TILs). Usually these are different types of cells of the immune system: natural killer cells (NK cells), B-lymphocytes, monocytes, but T-lymphocytes predominate among them. Since lymphocytes kill tumor cells, their presence in it increases the success of treatment. Since the 1990s, Dr. Rosenberg has been studying TILs in an effort to achieve their greater effectiveness.

Initially, Rosenberg and his colleagues were engaged in the use of lymphocytes penetrating into the tumor in the fight against one of the varieties of melanoma. They extracted cells from the tumor, multiplied them in the laboratory, and then returned them to the patient's body. As a result, they managed to raise the percentage of remission in such patients from 20% to 25%.

Then they began experiments on the treatment of cancer of the digestive system, in particular the pancreas and intestines. Scientists determine which mutations are contained in the patient's tumor cells, and study lymphocytes that are able to detect and attack cells with the same mutations without damaging healthy cells.

Celine Ryan had a severe form of colon cancer that metastasized to the lungs. It was not possible to defeat the tumor, despite surgery, chemotherapy and radiation. Then Ryan began to look for research centers where new treatment methods are being developed in order to offer her participation in clinical trials. That's how she found out about the TILs research project at the National Cancer Institute. Contacting the researchers and providing her data, she was refused, as the size of her tumor was considered too small to receive lymphocytes. A year later, she was again refused to be included in the experiment, citing the same reason. Then Ryan herself measured the tumor on the pictures of her lungs and made sure that they met the criteria of the study. She wrote a polite letter to the institute, pointing out this fact and asking to explain why her tumor is not suitable. After that, she was invited to participate in the trials.

Doctors performed a surgical operation, receiving fragments of the tumor and lymphocytes of Celine Ryan for examination. Then it turned out that a mutation in the KRAS gene was observed in the patient's tumor cells. And among her T-lymphocytes there are those that target this mutation, since there is a special protein associated with this mutation on the cell surface in her body, which is recognized by T-lymphocytes. As a result of the treatment, the tumors in Celine Ryan's body were destroyed.

The best news is that the type of KRAS mutation that Celine Ryan had is also present in a large number of other patients with pancreatic or intestinal cancer. According to scientists, for colorectal cancer, their share is 13%. Accordingly, these people may become likely candidates for treatment with the help of lymphocytes penetrating the tumor.

Colorectal cancer is very common. In the USA in 2016, there were more than 95,000 cases of colon cancer and 39,000 cases of rectal cancer, about 49,000 patients died. Worldwide, as of 2012, 1.4 million cases of colorectal cancer were recorded and 694,000 patients died. Pancreatic cancer, which is even more often associated with mutations in the KRAS gene, is considered one of the deadliest types of cancer. In 2016, there were about 53,000 cases of pancreatic cancer in the United States and almost 42,000 patient deaths. The five-year survival rate for this type of tumor is less than 10%. Worldwide, according to 2012 data, about 330,000 people died from pancreatic cancer.

Portal "Eternal youth" http://vechnayamolodost.ru  14.12.2016

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