Multiple myeloma, the second most common blood cancer in the United States, is more common in men with an estimated 20,030 new male cases in 2025. The reasons for this disparity are unclear.

In a new study published in Cancer, researchers from the UAB Marnix E. Heersink School of Medicine’s Department of Pathology found that male patients were more likely to have advanced stage of the disease at the time of diagnosis.

“To our knowledge, our findings are the first to provide evidence that men present at diagnosis with greater tumor burden and that advanced age, together with male sex, is an important driver for the observed differences,” said Krystle Ong, PhD, first author of the study and researcher in the Division of Molecular and Cellular Pathology.

UAB analyzed data from 850 patients with newly diagnosed multiple myeloma, where 54 percent were male with a median age of 62. They were more likely to have higher serum monoclonal protein levels, an abnormal protein produced by cancerous blood cells, and a higher prevalence of organ damage, including lytic bone lesions and impaired kidney function.

“We plan to conduct future studies to fill in the gaps of our understanding of the relevant sex-specific mechanisms underlying multiple myeloma pathogenesis,” Ong said. “Understanding these key factors may lead to improved risk stratification, diagnosis and clinical treatments for both men and women with early precursor conditions that lead to multiple myeloma.”