Blood levels of immune protein predict risk in Hodgkin disease
Blood levels of galectin-1, an immunity-related protein, in patients with newly diagnosed Hodgkin lymphoma reflected the extent of their cancer and correlated with other predictors of outcome.
A new laboratory test known as a sandwich ELISA allowed the measurements of galectin-1 to be made. Galectin-1 is a protein which, when overexpressed by Hodgkin lymphoma cells, allows them to evade the body's immune response that normally would detect the cancer and attack it with cell-killing lymphocytes. Antibodies were developed that recognize the galectin-1 protein and could be used to develop the sandwich ELISA assay.
Since the protein is secreted into the bloodstream, the investigators hypothesized that measuring relative levels of galectin-1 in newly diagnosed, untreated Hodgkin patients could help to assess likely outcomes in those patients. In turn, such predictions could help physicians decide how aggressively to treat the lymphoma. With further development, the assay could become an objective test to help make decisions on which treatment options to use for patients.
Scientists from Dana-Farber Cancer Institute in Boston collaborated with researchers of the German Hodgkin Study Group (GHSG) at the University Hospital of Cologne. GHSG has what is probably the largest, most comprehensive data on clinical trials of patients with well-defined Hodgkin lymphoma. The 315 patients whose blood levels of galectin-1 were tested in the study had been enrolled in three different clinical trials. One trial was for early-stage disease, one for early-stage disease with additional less-favorable risk factors, and a third for patients with bulky localized or advanced-stage disease.
The sandwich ELISA assay revealed that blood levels of galectin-1 in Hodgkin lymphoma patients were significantly higher than in normal control patients. Relative galectin-1 levels were correlated with the risk factors that had been used to assign the 315 patients to the three different clinical trials. The researchers noted that direct comparisons of galectin-1 levels with patients' outcomes are awaiting the completion of one of the clinical trials.
Besides its ability to assess outcomes, galectin-1 is also promising as a therapeutic target. The research group has also made a neutralizing antibody to block the protein, though it would still need to be humanized so it is compatible with human patients and then rigorously tested for safety and efficacy.This study was reported at the American Society of Hematology annual meeting, held December 8-11, 2012, in Atlanta, Georgia.