24 April 2017

Cancer relapses explained by "contagious" oxidation

Denis Strigun, Naked Science

Despite the relative effectiveness in the early stages, existing cancer therapies are significantly limited by the risk of recurrence and complications of the disease. At the same time, the pathogenesis and etiology of repeated malignant neoplasms have not been sufficiently studied. It is known that the probability of relapse increases the localization of the tumor: in particular, most types of skin cancer in the initial stages can be completely cured in 90-100 percent of cases, while rectal cancer often metastasizes to the lymph nodes. In addition, the likelihood of recurrent disease increases with the inaccessibility of the tumor (for example, brain cancer), which makes it difficult to perform surgical removal. At the same time, the operation itself can serve as a risk factor for relapse.

According to The Straits Times (Why healthy cells near tumours turn cancerous), in a new study, a group of Singaporean scientists described a possible molecular mechanism of recurrent malignant neoplasms. According to the results of the work, it is based on the effect on healthy tissues of hydrogen peroxide (H2O2), which is produced by cancer cells. Unlike preserved biomaterial, in the latter the content of the substance increases 5-10 times, and its sharp release is able to turn neighboring cells into pathogenic. According to the representative of the School of Biological Sciences of the institution, Andrew Tan, this leads to a domino effect: against the background of increased production of H2O2 in the environment, healthy tissues also begin to increase the concentration of the compound.

Possible mechanism of influence of hydrogen peroxide on tumor metastasis

It is noted that the negative effect, the so-called field of carcinization, can be observed at a distance of up to seven centimeters from the epicenter of the tumor. The authors suggest that it was not possible to establish a connection between relapses and hydrogen peroxide for a long time, since the substance practically does not linger in the human body. "After its release and cell damage, hydrogen peroxide disappears, so most studies could not identify the cause," Tan said. Past observations have shown that the compound produced only affects healthy cells, the scientist added. The authors were able to establish the spread of H2O2 by modeling the process in which normal cells were mixed with tumor cells. After in vitro experiments, the treated cells were injected into healthy animals, which led to the development of neoplasms.

The discovery is expected to allow doctors to more accurately determine the volume of tissue in preparation for surgical excision. The group is currently continuing to investigate the mechanism of H2O2 spread by cancer cells. The main goal of the work is to develop methods that prevent the growth of tumors, since in some cases it is impossible to remove healthy tissues adjacent to the affected cells.

Normally, hydrogen peroxide, along with other reactive oxygen species, is produced in living cells during metabolism, but its increased content is associated with oxidative stress. The latter is considered as an important component of a number of diseases, including diabetes, Alzheimer's disease and atherosclerosis.

Portal "Eternal youth" http://vechnayamolodost.ru  24.04.2017

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