Gene Activity May Affect Acute Myeloid Leukemia Outcome

For acute myeloid leukemia patients, overactive genes in their leukemic stem cells (LSC) can translate into a more difficult struggle to overcome their disease and achieve prolonged remission, new research reveals. "In many cancers, specific subpopulations of cells appear to be uniquely capable of initiating and maintaining tumors," the study authors explained in their report. The researchers identified 52 LSC genes that, when highly active, appear to prompt worse outcomes among acute myeloid leukemia (AML) patients.

Between 2005 and 2007, study author Andrew J. Gentles, of Stanford University in Palo Alto, Calif., and colleagues examined gene activity in a group of AML patients as well as healthy individuals. Separate data concerning AML tumors in four groups of patients (totaling more than 1,000) was also analyzed. In one of the patient groups, the investigators found that higher activity levels among 52 LSC genes meant a 78 percent risk of death within a three-year period. This compared with a 57 percent risk of death in the same time frame for AML patients with lower gene activity among these specific "signature" genes.

In another AML patient group, the research team observed that higher gene activity prompted an 81 percent risk for experiencing a disease set-back over three years, compared with just a 48 percent risk among patients with low gene activity. What's more, Gentles and his colleagues found that higher activity among these 52 LSC genes generally meant a poorer response to chemotherapy treatment and lower remission rates.

Docs Claim Transplant Cured Man of HIV, But Experts Urge Caution

In a rare case, a man living in Germany who had both leukemia and AIDS no longer has any detectable HIV cells in his blood following a stem cell transplant for his leukemia three years ago. But experts were quick to caution that the case does not have practical implications for the treatment of AIDS worldwide. As it turns out, the donor for that transplant carried a rare mutation in a gene that increases immunity against the most common form of HIV.

First reported in 2009, this follow-up study, published online in the journal Blood, confirms that the recipient patient is still free of both leukemia and HIV three years after the transplant. But one expert issued strong words of caution in interpreting the finding. "Our phones have been ringing off the hook," said Dr. Margaret Fischl, director of the AIDS clinical research unit at the University of Miami Miller School of Medicine. "We are having patients calling us and asking if they can stop their antiretroviral therapy and the answer is uncategorically no."

The theory is that if you could wipe out every infected cell you could cure HIV, Fischl said, but this is a unique case. The patient had intense chemotherapy and radiation, then relapsed and was given a second transplant from the same donor. The donor was unique in that he had a gene that could fight the most common form of HIV. This mutation is seen in about one in every million people, Fischl explained.

Researchers Turn Stem Cells Into Intestinal Tissue in Lab

Researchers say they've turned human stem cells into functioning human intestinal tissue in a laboratory setting. The study team described its accomplishment as a "significant step" forward in efforts to better understand the function and development of the human intestine. They also expressed hope that the innovation will spur the development of new strategies to combat intestinal diseases, while opening up new avenues for the generation of transplantation tissue.

"The hope is that our ability to turn stem cells into intestinal tissue will eventually be therapeutically beneficial for people with diseases such as necrotizing enterocolitis, inflammatory bowel disease and short bowel syndromes," explained study senior author James Wells, a researcher in the division of developmental biology at Cincinnati Children's Hospital Medical Center, in a hospital news release. Wells and his colleagues report their findings in the Dec. 12 online issue of Nature.

The authors used two types of so-called "pluripotent" stem cells -- cells that have the chameleon-like ability to differentiate into any one of about 200 distinct cell types. Human embryonic stem cells, which are known to have such transformative abilities, were one type. For the other, the researchers looked to "induced" stem cells cells harvested from patients and reprogrammed in the lab to function as pluripotent stem cells. Though less well-tested than embryonic stem cells, induced cells theoretically have the advantage of minimizing the risk for cell rejection when replanted back into the host patient.