Dr. Serdar Bulun, the chairman of obstetrics and gynecology at Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital, said the single cell activates other cells to join its frenzied expansion.
"It loses its way and goes wild," Bulun said in a statement. "No one knew how these came about before. The stem cells make up only 1.5 percent of the cells in the tumor, yet they are the essential drivers of its growth."
Dr. Masanori Ono, a post-doctoral student in Bulun's laboratory who was the study's lead author, said the stem cell that initiated the tumor carries a mutation called MED12.
Recently, mutations in the MED12 gene have been reported in the majority of uterine fibroid tissues. Once the mutation kicks off the abnormal expansion, the tumors grow in response to steroid hormones, particularly progesterone, Bulun said.
"Understanding how this mutation directs the tumor growth gives us a new direction to develop therapies," Bulun said in a statement.
The paper is published in the journal PLoS ONE.