Scientists have discovered that the most dangerous cancer of the uterine lining closely resembles the worst ovarian and breast cancers, providing the most telling evidence yet that cancer will increasingly be seen as a disease defined primarily by its genetic fingerprint rather than just by the organ where it originated.
The study of endometrial cancer — the cancer of the uterine lining — and another of acute myeloid leukemia, reported on simultaneously recently by Nature and the New England Journal of Medicine, are part of a sprawling, ambitious project by the National Institutes of Health to scrutinize DNA aberrations in common cancers.
“This is exploring the landscape of cancer genomics,” said Dr. David Steensma, a leukemia researcher at the Dana-Farber Cancer Institute who was not involved with the studies. “This is a landmark that will stand the test of time.”
The main investigator on the endometrial cancer part of the research, Dr. Douglas Levine of Memorial Sloan Kettering Cancer Center, said his team scoured the country for tumor samples. Endometrial cancer is the most common gynecological cancer in U.S. women and strikes nearly 50,000 of them a year, killing about 8,000.
The cancer has long been evaluated by pathologists who examine thin slices of endometrial tumors and put them in one of two broad categories. But the method is not ideal.
Pathologists often disagree about how to classify the tumors and can find it difficult to distinguish between the two types, Levine said.
The new genetic analysis found genetic patterns that more precisely classify the tumors into four groups. About 10 percent of tumors that had seemed easily treated under the old classification now appear to be more deadly. Another finding: Many endometrial cancers had a mutation seen before only in colon cancers.
“That was a complete surprise,” Levine said.
It turned out to be good news, a sign of cancers that have better outcomes.
Another surprise: The worst endometrial tumors were very similar to the most lethal ovarian and breast cancers, raising the tantalizing possibility that the three deadly cancers might respond to the same drugs.