What’s the News: After a bone marrow transplant cured a Berlin man of HIV in 2008, scientists have been working to see whether similar, though less drastic, measures could be a treatment for the disease. And judging from the results of a recent clinical trial that used gene therapy to accomplish the goal, there’s potential.
What’s the Context:
- In the original case, an HIV-positive patient was diagnosed with leukemia, and after having chemotherapy to knock down his cancer, he received multiple transplants of blood stem cells from a donor, which took up permanent residency in his body.
- Those stem cells had a rare mutation that deactivated the CCR5 receptor, which the HIV virus uses to enter the blood cells it destroys. The end result was that the patient became the first person in the world to be cured of HIV—with that receptor out of commission, the virus couldn’t grow, and he longer has any detectible levels of HIV.
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What’s the News: Medicine in the age of genes overflows with daring new techniques and treatments, from personalized chemotherapy to prenatal genetic testing, each heralded as a game-changer. But rarely do we get an assessment of a treatment’s long-term good, which is why recent papers following up on one of the most controversial genetic treatments, gene therapy, are making waves: though one patient developed leukemia from the treatment, 13 of 16 kids treated with gene therapy for a severe immune disorder at least 9 years ago have been cured, adding to the sense that the field is on its way to recovery from early setbacks.
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Modified immune cells decimated chronic lymphocytic leukemia, scientists found.
What’s the News: Striking results in a very small study have got the web a-buzz about a new cancer treatment: With three leukemia patients at the ends of their ropes, scientists modified some of their immune cells with a gene that enabled them to hunt down cancer cells. Remarkably, the treatment wiped out more than two pounds of tumor tissue in each patient, and the three have now been in remission for a year.
But what weight does such a small study carry, what about the side effects, and what do these results mean for people with other cancers?
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What’s the News: Scientists have identified three gene mutations that lead to acute myeloid leukemia, a cancer that afflicts white blood cells, which may lead to better cancer drugs in the future. As Wellcome Trust Sanger Institute hematologist George Vassiliou told the BBC, his team’s study “found critical steps that take place when the cancer develops. Identifying the biological steps … means we can look for new drugs to reverse the process.”
How the Heck:
- The researchers discovered the major mutation by switching on the Npm1 gene in mice: They observed that about one third of the mice went on to develop leukemia.
- They knew some other genes were involved because not all the mice contracted cancer. So next, they randomly mutated mouse genes, and then analyzed the mutations in the ones that developed cancer, identifying two other mutations in the process. The second mutation affected cell growth and division and the third affected the cell’s environment.
What’s the Context:
Not So Fast: Researchers caution that it could take decades before new cancer-fighting drugs based on this study come on the market. This present study only used mice as subjects.
Reference: George S Vassiliou et al. “Mutant nucleophosmin and cooperating pathways drive leukemia initiation and progression in mice.” Nature Genetics. doi:10.1038/ng.796
Image: Wikimedia Commons / Bruce Wetzel
Perhaps you’ve seen the story of the 44-year-old American man reportedly “cured” of HIV in Germany–it’s been making the rounds over the past week. What’s actually happening here?
The Procedure
This is a story that dates back a few years; in fact, 80beats blogged about this case years ago when it first made the news. Back in 2007, the man—Timothy Ray Brown—was an HIV-positive patient suffering from acute myeloid leukemia. When standard chemotherapy couldn’t help him, his docs in Germany turned to a bone marrow transplant, with one twist.
Brown’s oncologist decided to look for a bone marrow donor who had a had a special genetic mutation that made the stem cells in it naturally resistant to HIV infection. His physician, Dr. Gero Huetter, was able to find this rare match and Brown got the bone marrow transplant. He needed a second stem cell transplant because the cancer came back. Today, he appears to be cancer free and doctors can’t find traces of the virus that causes AIDS either. [CNN]
Brown’s treatment made a splash in the news in 2008, when the doctors first reported on it. It has resurfaced this month because the researchers published a new study in the journal Blood updating his condition.
The researchers confirmed that Brown seems to have maintained his resistance to HIV for three years, confounding their expectation that he would become reinfected. They concluded that a “cure of HIV has been achieved in this patient.” [New Scientist]
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The latest entry into the cellphones-radiation-health debate is a British study of thousands of children, which investigated whether the proximity of pregnant women to cellphone towers had any effect on whether their kids developed tumors or leukemia. The result: a big no.
Researchers from Imperial College London identified 1,397 children under five who were diagnosed with leukaemia or a tumour of the brain or central nervous system between 1999 and 2001. They compared each child with four children of the same gender who were born on the same day but had not developed cancer [The Guardian].
They then cross-compared all those children to how much radiation their mothers likely received during pregnancy, based on a survey of more than 80,000 cell towers and their radiation output. No matter how they ran the numbers, the team couldn’t find a significant effect.
For instance, the mothers whose children were diagnosed with cancer lived an average of 1,173 yards from a cellphone tower while they were pregnant — statistically indistinguishable from the 1,211 yards that separated the other pregnant women from their nearest cellphone towers. Tallying up the total power output of all cellphone towers within 766 yards of each pregnant woman’s home, they found that both groups had nearly the same exposure — 2.89 kilowatts for the mothers of cancer victims and 3.00 kilowatts for the other mothers [Los Angeles Times].
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In very rare cases, the womb is a dangerous place for a developing fetus. Researchers have found that pregnant women can pass on cancer cells to their unborn babies, if those cancer cells carry a particular genetic mutation. The new study resolves a longstanding puzzle, because in theory any cancer cells that manage to cross the placenta into the baby’s bloodstream should be targeted for destruction by the child’s immune system. But there are records of 17 cases of a mother and baby appearing to share the same cancer – usually leukaemia or melanoma [BBC News].
In the study, which will be published in Proceedings of the National Academy of Sciences, researchers used a genetic “fingerprinting” technique to match the cancer cells found in a mother and baby. The case, involving a Japanese mother aged 28 and her daughter, revealed that both patients’ leukaemic cells carried the identical mutated cancer gene BCR-ABL1 even though the infant had not inherited this gene [The Times]. This meant that the child, who was diagnosed with cancer at the age of 11 months, could not have developed leukemia independently.
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In a remarkable announcement, German researchers have declared that they “functionally cured” a patient of AIDS, eradicating all traces of the virus from his body. The feat was accomplished with a bone marrow transplant from a donor who had a genetic resistance to the virus, and researchers say that 20 months later they can find no trace of the virus in the patient’s blood, bone marrow, or organ tissue.
But the accomplishment shouldn’t be taken as a sign that a cure for the 33 million people living with AIDS is around the corner, researchers are hasty to add. Professor Rodolf Tauber from the [German] clinic said: “This is an interesting case for research. But to promise to millions of people infected with HIV that there is hope of a cure would not be right” [BBC News]. Reasons for this caution include the small number of potential donors with the HIV-resistant mutation, and the difficulty and expense of bone marrow transplants.
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For the first time researchers have sequenced the complete genome of a cancer cell, and they say the process turned up eight previously unknown genetic mutations that played a role in the patient’s terminal leukemia. As it gets cheaper and easier to decode entire genomes, as opposed to just checking “usual suspect” stretches of DNA, doctors hope to decode the genomes of many different types of cancer. Eventually, researchers say cheap techniques may allow doctors to study the cancer genomes of individual patients.
Lead researcher Richard Wilson said he hoped that in 5 to 20 years, decoding a patient’s cancer genome would consist of dropping a spot of blood onto a chip that slides into a desktop computer and getting back a report that suggests which drugs will work best.“That’s personalized genomics, personalized medicine in a box,” he said. “It’s holy grail sort of stuff, but I think it’s not out of the realm of possibility” [The New York Times].
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A leukemia drug has shown great promise in treating multiple sclerosis patients, decreasing neurological symptoms and in some cases even allowing patients to rebuild damaged brain tissue, according to a new study.
Lead researcher Alasdair Coles says the findings offer new hope to patients suffering from the incurable disease: “Not only can this drug stop the disease in its tracks it can reverse patients disabilities. They can walk farther and work for longer. Their lives have started again. This was not expected, the best anyone thought we could hope for with MS drugs was to prevent the condition getting any worse” [Telegraph]. But the drug, named alemtuzumab, also caused some serious side effects that researchers are still investigating.
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