Massachusetts General Hospital (MGH) researchers have identified potential ovarian cancer stem cells, which may be behind the difficulty of treating these tumors with standard chemotherapy. Understanding more about the stem-like characteristics of these cells could lead to new approaches to treating ovarian cancer, which kills more than 16,000 U.S. women annually and is their fifth most common cause of cancer death. The report will appear in the July 25 Proceeding of the National Academy of Sciences (PNAS) and has received early online release.
"We feel these stem-like cancer cells may be resistant to traditional chemotherapy and could be responsible for the ultimately fatal drug-resistant recurrence that is characteristic of ovarian cancer," says Paul Szotek, MD, of the MGH Pediatric Surgical Research Laboratories, first author of the PNAS report. "We believe this likely is the first time stem-like cells have been found in models of ovarian cancer and in cells associated with human ovarian cancer."
Several recent studies have identified tiny populations of tumor cells that appear to act like stem cells, driving the tumor's ability to grow and spread. If some of these specialized cells escaped destruction by chemotherapy or radiation, the tumor would be able to recur quickly, often in a form resistant to chemotherapy. Similar cancer stem cells have been previously identified in leukemia and breast cancer and in cell lines of central nervous system and gastrointestinal tumors.
Standard treatment for ovarian cancer surgical removal of all involved tissues followed by chemotherapy usually appears successful, but treatment-resistant tumors recur in the vast majority of patients, leading to a five-year survival rate of less than 30 percent. Those factors and other observations suggested that cancer stem cells may also be found with ovarian tumors, leading to the current study.