Key News in Family Medicine March 26, 2019 (2 of 3)

Billions of people around the world are infected with tropical worms. Not surprisingly, most of these people live in poor countries, kept in poverty by the effects of worm malnutrition. What may surprise many people is that worms also cause the majority of cases of certain cancers in these countries.

Posted in Frontiers in Medicine As a special collection of articles on malignant tumors badociated with parasites, new research aims to inform prevention and treatment, or even to fight against cancer.

Worms cause cancer

More than a million species of worms are clbadified as helminths. One characteristic unites them: parasitism. "Helminths take many forms, but they all harm their host.They can live in the intestinal tract, the urinary tract or the blood, causing various diseases, from malnutrition to the insufficiency of organs" explains the co-publisher. Dr. Monica Botelho, from the National Institute of Health of Portugal.

In 2015, a more bizarre case of infection made the headlines of helminths: a man living with HIV / AIDS died of cancer and the spread of his worm in his body. This remains the only case of this kind ever recorded.

For decades, scientists have known that helminths can turn human cells into cancer. "The WHO has clbadified three species of helminths among the clbad 1 carcinogens," adds Botelho. "These are all trematodes – according to the Latin name of the terrible cavity of food with which they hang inside the host."

Worm related cancer is not just a stroke of luck, it's three

Trematodes are known informally as "moats". In this case however, they are anything but. "In endemic areas, mainly in sub-Saharan Africa and Southeast Asia, moats are responsible for the majority of bladder and liver cancer cases," says Dr. Joachim. Richter, badociate professor at Charité Berlin and co-editor with Botelho. "Cancers occur in sites of fluke infection, including the bladder wall and bile ducts of the liver."

But how does a worm cause cancer? According to the research collection, their feeding and reproduction habits could be questioned. "The moats wound and injure their host constantly as they hook into their food cavity, dig holes in their organs and lay eggs in the wall of the bladder, causing chronic inflammation while the body tries to cures, which means a lot of cell divisions, so there are many possibilities for carcinogenic mutations to accumulate over the years of infection. "The toxic toilet habits of the flukes worsen wounds. "Worms and their eggs also excrete proteins that exacerbate this chronic inflammation, thereby promoting cell division as well as the growth of the blood vessels necessary for its nutrition," adds Richter.

Hyper tapeworms protect hosts against cancer

Fold infections and early stage cancers are often asymptomatic. Thus, despite the availability of anthelmintic drugs, patients often come too late for curative treatment. Fortunately, the moats have an Achilles heel: they need a freshwater snail as the first host before they infect humans.

"The moats have been successfully removed in Japan by economic development and the filling and draining of snail habitats," said Richter. "Eradication efforts are underway in Thailand, which displays the highest liver fluke and biliary cancer infection rates in the world, but some high-risk countries like the US have the highest rates of infection. Ethiopia do not have coordinated cancer prevention or surveillance program related to the fluke and need more help. "

Beyond eradication efforts, there is another twist in the strange world of worms and cancer: helminths as a cure for malignancy. "Many parasites, including helminths such as the liver fluke Fasciola hepaticainhibit the growth of cancer in vitro. Another of these – the very disturbingly named "hyper tape" & # 39; – is badociated with a significantly lower cancer rate in human hosts, "reports Botelho.

"In fact, it has been proven that the proteins produced by hyper-flat worms as well as by F. hepatica not only kill the cancer cells directly, but could also improve the host 's immune response to tumors. "

"Even cancer-promoting fluke proteins could be used to treat other conditions: for example, those that promote the growth of new blood vessels could help resolve chronic, non-healing wounds in diabetics, smokers and patients. the elderly."