This photo taken on July 24, 2025 shows researchers posing for a group photo at the College of Future Technology, Peking University (PKU) in Beijing, capital of China. (PKU/Handout via Xinhua)

Chinese scientists have identified a key target in the treatment of adenomyosis, a condition affecting tens of millions of women of reproductive age worldwide, offering hope for safer and more effective therapeutic options.

Adenomyosis is a common gynecological condition characterized by the growth of endometrial tissue within the uterine muscular layer. Its main clinical manifestations include dysmenorrhea, menorrhagia, chronic pelvic pain and infertility.

Currently, hormone therapy targeting estrogen and progesterone signaling is commonly used to treat this disease. Although it can alleviate symptoms -- it also has serious side effects such as fertility suppression and osteoporosis. Due to the unclear pathogenesis of adenomyosis, no new therapeutic targets have been identified by scientists over the past four decades, severely limiting the development of new drugs.

Chinese scientists have identified the prolactin receptor as the key target driving adenomyosis. For the first time, they demonstrated that abnormal activation of prolactin signaling is directly related to adenomyosis -- and verified the potential of monoclonal antibody drugs targeting the prolactin receptor for treatment of this disease.

The study was jointly conducted by a research team from Peking University (PKU) led by Xiao Ruiping and Hu Xinli, together with Zhu Lan's team from Peking Union Medical College Hospital. Their findings were published in the international academic journal Signal Transduction and Targeted Therapy.

Prolactin is a hormone that promotes mammary gland development and lactation. The prolactin receptor is a protein located on the cell membrane. Prolactin signals are transmitted into the cell through the receptor, triggering a series of cellular responses.

Researchers have found, through analysis of 13 clinical samples, that prolactin signaling is abnormally active in the endometrium and ectopic lesions of patients. This signaling plays a significant role in the proliferation of ectopic endometrial cells and uterine tissue fibrosis, thereby promoting disease progression, Hu said.

Researchers have completed a Phase II clinical trial of the antibody drug HMI-115 for endometriosis. Clinical results from over one hundred patients demonstrated the drug's safety and efficacy.

Notably, this study confirms the effectiveness of targeting prolactin and its receptor as a therapeutic approach for adenomyosis -- deepening understanding of its pathogenesis, said Xiao, dean of the College of Future Technology at PKU.

"Traditional hormonal drugs inhibit pregnancy and are unfriendly to fertility," she said. "The advancement of drug development targeting the prolactin receptor will not only alleviate patients' pain but also holds the promise of completely resolving the dilemma between treatment and infertility."