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The East African : October 26th 2013
The EastAfrican OUTLOOK OCTOBER 26 - NOVEMBER 1, 2013 S CI E N C E Breaking through cancer’s shield Resea≥che≥s discove≥ed that they could b≥eak into the shield using the ≥ight d≥ugs By GINA KOLATA New York Times News Service F or more than a century, researchers were puzzled by the uncanny ability of cancer cells to evade the immune system. They knew cancer cells were grotesquely abnormal and should be killed by white blood cells. In the laboratory, in Petri dishes, white blood cells could go on the attack against cancer cells. Why, then, could cancers survive in the body? The answer, when it finally came in recent years, arrived with a bonus: a way to thwart a cancer’s strategy. Researchers discovered that cancers wrap themselves in an invisible protective shield. And they learned that they could break into that shield with the right drugs. When the immune system is free to attack, cancers can shrink and stop growing or even disappear in lucky patients with the best responses. It may not matter which type of cancer a person has. What matters is letting the immune system do its job. So far, the drugs have been test- ed and found to help patients with melanoma, kidney and lung cancer. In preliminary studies, they also appear to be effective in breast cancer, ovarian cancer and cancers of the colon, stomach, head and neck, but not the prostate. It is still early, of course, and questions remain. Why do only some patients respond to the new immunotherapies? Can these responses be predicted? Once beaten back by the immune system, how long do cancers remain at bay? Still, researchers think they are seeing the start of a new era in cancer medicine. “Amazing,” said Drew Pardoll, the immunotherapy research director at Johns Hopkins School of Medicine. “This BRIEFS New tech device can detect infected and healthy cells New technologies being studied by scientists affiliated with the Massachusetts Institute of Technology may be able to help doctors detect diseases at the point of impact using the electrical makeup of infected cells. The device can differentiate between early-stage infected cells and healthy ones by the specific electrical signal they give off. The researchers say the technology would enable doctors to read cell changes, even prescribe medicine, within those first crucial hours. African women scientists to benefit from funds EVADING DESTRUCTION Cancers evade attacks using the body’s own brakes. One braking system, for example, uses a molecule, PD-1, on the surface of T-cells of the immune system. If a target cell has molecules known as PD-L1 or PD-L2 on its surface, the T-cell cannot attack it. So some cancer cells drape themselves in those molecules. Cancers that do not use PD-L1 or PD-L2 are thought to use other similar systems, just starting to be explored. Body systems have a lot of redundancy to tamp down immune attacks. But for now, the PD system showed researchers how cancer cells can evade destruction. This period will be viewed as an inflection point, a moment in medical history when everything changed.” Drew Pardoll, Immunotherapy research director Johns Hopkins School of Medicine period will be viewed as an inflection point,” he said, “a moment in medical history when everything changed.” “A game-changer,” said Renier J Brentjens, a leukaemia specialist Researchers have been able to break the invisible protective shield that protects cancer cells using immunotherapy drugs. Picture: AFP at Memorial Sloan-Kettering Cancer Centre. Researchers and companies say they are only beginning to explore the new immunotherapies and develop others to attack cancers, like prostate, that seem to use different molecules to evade immune attacks. They are at the earliest stages of combining immunotherapies with other treatments in a bid to improve results. “I want to be very careful that we do not overhype and raise patients’ expectations so high that we can never meet them,” said Alise Reicin, a vice president at Merck for research and development. But the companies have an incen- tive to speed development of the drugs. They are expected to be expensive, and the demand huge. Delays of even a few months mean a huge loss of potential income. Nils Lonberg, a senior vice presi- dent at Bristol-Myers Squibb, said that immunotherapy carries a huge advantage over drugs that attack mutated genes. The latter approach all but invites the cancer to escape, in the same way bacteria develop resistance to antibiotics. By contrast, immunotherapy drugs are simply encouraging the immune system to do what it is meant to do; it is not going to adapt to evade the drugs. The story of the new cancer treatments started with the discovery of how cancers evade attacks. It turned out that they use the body’s own brakes, which normally shut down the immune system after it has done its job killing virus-infected cells. The first indication that a can- cer’s protective shield might be breached came in 2010, after a trial of the drug ipilimumab in patients with otherwise untreatable melanoma. The drug unleashes the immune system, letting it overwhelm tumours even if they have a protective shield. Patients who took the drug sur- vived an average of 10 months, or four months longer than those randomly assigned to a different treatment. And about 20 per cent of patients who responded have now survived up to 10 years. It was the first drug to improve survival for patients with metastatic melanoma in a randomised trial. WHO links ai≥ pollution to lung and bladde≥ cance≥s By CHRISTABEL LIGAMI Special Correspondent EXPOSURE TO air pollution causes lung cancer and leads to an increased risk of contracting cancer of the bladder, a new analysis by the World Health Organisation shows. After reviewing the latest scientific literature, dozens of the world’s leading experts convened by the International Agency for Research on Cancer (IARC) under the WHO concluded that there is sufficient evidence to show that exposure to outdoor air pollution causes lung cancer. They also noted a positive association of increased risk of bladder cancer. The IARC’s evaluation focused on more than 1,000 scientific papers from studies on five continents. The reviewed studies analysed the car- cinogenicity of various pollutants present in outdoor air pollution, especially particulate matter and transportation-related pollution. Particulate matter, a major component of out- door air pollution, was evaluated separately and was also classified as carcinogenic to humans. This showed an increasing risk of lung can- cer with higher levels of exposure to particulate matter and air pollution. Although the composition of air pollution and levels of exposure can vary dramatically between locations, WHO said that the conclusions of the Working Group apply to all regions of the world. “The air we breathe has become polluted with a mixture of cancer-causing substances,” said Kurt Straif, head of the IARC Monographs Section. “We now know that outdoor air pollution is not only a major risk to health in general, but also a leading environmental cause of cancer deaths.” Air pollution is already known to increase risks for a wide range of diseases, such as respiratory and heart diseases. Studies indicate that in recent years exposure levels have increased significantly in some parts of the world, particularly in rapidly industrialising countries with large populations. The most recent WHO data indicates that in 2010, 223,000 deaths from lung cancer worldwide resulted from air pollution. In the past, studies have focused on many individual chemicals and specific mixtures that occur in outdoor air pollution. But this is the first time that experts have classified outdoor air pollution as a cause of cancer. The Organisation for Women in Science for the Developing World (OWSD) plans to develop mentoring programmes and raise funds to assist female scientists in developing countries. This will see an increase in the number of awards and post doctorate fellowships given to female scientists from developing countries and fund young female scientists attending international conferences. OWSD, which is partly funded by The World Academy of Sciences, was launched in 1993 to improve women’s representation in science and technology research, teaching and leadership. Canadian researchers develop Ebola antibody A new antibody treatment developed by Canadian researchers may help prevent Ebola related deaths, even when given three full days after a person has been infected. The findings, published in the US journal Science Translational Medicine, suggested that it may be possible to develop a cure for Ebola even after the virus is detected in the blood and symptoms have become apparent. The breakthrough will help countries like Uganda that suffer several episodes of Ebola every year since 2000. 35 Doctors observe a patient diagnosed with Ebola. Pic: FILE HIV/Aids’ gains made in Uganda now reversing After decades of leading global efforts to halt and bring down the spread of HIV/Aids, a new report shows that Uganda is currently experiencing a worrying reversal of trends. The report by the country’s Ministry of Education showed that 353 new infections occur every day while 60,000 Ugandans die every year of HIV/Aids. “Trends in maternal mortality and HIV/Aids are particularly worrying,” said Ahunna Eziakonwa-Onochie, the UN Resident Co-ordinator and UNDP Resident Representative.
October 21st 2013
November 3rd 2013