A decision to rename myeloproliferative neoplasms led to a plethora of developments in a space where there was once little interest.
To a greater extent, how would the evolution of the term myeloproliferative disorders (MPDs) — a group of diseases including polycythemia vera (PV), primary myelofibrosis (PMF) and essential thrombocythemia (ET) — to myeloproliferative neoplasms (MPNs) affect the lives of thousands upon thousands of people living with a rare disease?
As it turns out, that decision would transform the trajectory of a cancer space where there was once very little interest.
What’s in a Name?
In 2008, the World Health Organization (WHO) in collaboration with the United States-based Society for Hematopathology and the European Association for Haematopathology published a revised classification of the diseases that made up MPDs and officially classified them as neoplasms.
“They were considered a ‘disorder’ and then a ‘neoplasm,’” says David Ricci, a long-time member of the MPN Research Foundation Board of Directors. “The diseases had not changed. There was nothing about these diseases that was different before the change versus after the change.”
Instead, the change of name was made largely to be more accurate, Ricci
David Ricci notes that until about 15 to 20 years ago, the incidence of MPNs was not well studied.
Photo provided by David Ricci
explains. The term MPDs dates back to a former president of the American Society of Hematology, Dr. Louis Wasserman, who coined the phrase to describe a range of diseases that had elevated blood counts, including chronic myeloid leukemia (CML), notes Dr. Ruben Mesa, executive director of Mays Cancer Center at UT Health San Antonio MD Anderson Cancer Center.
In PV, patients experience an increase in all blood cells, particularly red blood cells, which supply oxygen. Patients with ET have bone marrow that produces too many platelets, which can cause abnormal bleeding or blood clots. And in PMF, patients build up scar tissue in the bone marrow that produces blood cells, impairing the body’s ability to make normal blood cells.
“Over time we learned that all of these were neoplasms,” Mesa says. “All of the abnormal cells are related to one another, and that is a defining charac-teristic of a neoplasm.”
This characteristic is called clonality. Neoplasms are an abnormal growth of cells that can be either benign or malignant. MPNs start out as benign but may progress to being malignant.
“As science progressed and we learned this was a clonally driven disease, that sounded more like cancer,” says Dr. Michael R. Savona, head of hematology, cellular therapy and stem cell transplantation at Vanderbilt University Medical Center in Nashville, Tennessee.
“It would have been technically inaccu-rate to consider it otherwise.”