"TRAIL-R2 is also a key mediator of apoptosis but its clinical implications and epigenetic regulation in breast cancer are not clearly understood."
BUFFALO, NY – June 24, 2026 – A new research paper was published in Volume 17 of Oncotarget on June 9, 2026, titled " TRAIL-R2 in the shadows: Epigenetic silencing and clinical implications in breast cancer ."
The study was led by first author Nuzhat Khursheed from the University of Kashmir and corresponding authors Asia Asiaf from the Central University of Kashmir and Showkat Ahmad Ganie from the University of Kashmir .
Breast cancer remains one of the most common cancers affecting women worldwide. While advances in diagnosis and treatment have improved outcomes for many patients, researchers continue to investigate the molecular changes that enable tumor cells to survive, grow, and spread. One process receiving increasing attention is epigenetic regulation, in which genes are switched on or off without altering the underlying DNA sequence.
In this study, researchers examined TRAIL-R2, also known as death receptor 5 (DR5), a protein that plays an important role in triggering apoptosis, the programmed cell death process that helps eliminate damaged or abnormal cells. Loss of apoptotic signaling is a hallmark of cancer, but the clinical significance and epigenetic regulation of TRAIL-R2 in breast cancer have remained incompletely understood.
The investigators analyzed matched tumor and adjacent normal breast tissue samples from 67 patients. Using methylation-specific PCR, quantitative real-time PCR, and western blotting, they evaluated TRAIL-R2 promoter methylation as well as its gene and protein expression levels.
The analysis revealed that TRAIL-R2 was frequently silenced in breast tumors. More than half of tumor samples showed promoter hypermethylation, a chemical modification that can suppress gene activity. At the same time, both TRAIL-R2 mRNA and protein expression levels were significantly lower in tumor tissues than in adjacent normal breast tissue.
Further analysis demonstrated that TRAIL-R2 hypermethylation was more common in invasive ductal carcinoma, the most common subtype of breast cancer, and in patients with a history of oral contraceptive use. Reduced TRAIL-R2 expression was also associated with advanced tumor stage and several clinicopathological features linked to more aggressive disease.
The researchers observed a strong inverse relationship between promoter methylation and TRAIL-R2 expression, suggesting that epigenetic silencing may contribute directly to loss of this important apoptotic receptor. Tumors with reduced TRAIL-R2 activity may become less susceptible to programmed cell death, potentially allowing cancer cells to survive and progress.
The study also found that lower TRAIL-R2 protein expression was associated with postmenopausal status. In addition, patients with higher TRAIL-R2 expression tended to show better overall survival, although larger studies will be needed to further evaluate its prognostic value.
"These results suggest that aggressive clinicopathological phenotypes are associated with TRAIL-R2 silencing via promoter hypermethylation that may be relevant as a prognostic biomarker and therapeutic target in breast cancer."
According to the authors, restoring TRAIL-R2 activity could represent a potential therapeutic strategy. Because DNA methylation is reversible, treatments that target epigenetic modifications may help reactivate TRAIL-R2 expression and improve responsiveness to apoptosis-based cancer therapies.
Overall, this study provides new evidence that epigenetic silencing of TRAIL-R2 is associated with reduced expression of a critical cell death receptor and with features of more aggressive breast cancer. The findings highlight the potential value of TRAIL-R2 as both a biomarker and a therapeutic target, while underscoring the growing importance of epigenetic mechanisms in cancer progression.
DOI: https://doi.org/10.18632/oncotarget.28891
