Dogs have proven far superior to mice as models for prostate cancer research. In a recent study, scientists uncovered key pathways cancer uses to dodge the immune system and identified an antibody that significantly boosted survival rates.
Prostate cancer remains the most common cancer in men, affecting about 1.2 million people annually worldwide and causing 359,000 deaths. Androgen suppression therapy, often combined with chemotherapy, works initially in 80-90% of advanced cases. Yet, resistance often develops, underscoring the need for durable new treatments.
Cancer employs sophisticated strategies to evade the immune system. Recent research shows some cells enter dormancy to survive chemotherapy, explaining poor responses and late recurrences years after treatment.
Cancer also co-opts immune cells like regulatory T cells (Tregs), which normally prevent autoimmune attacks by marking 'self' cells. Tumor cells hijack this by tricking Tregs into protecting them, allowing unchecked growth and spread.
Elevated Tregs appear in many cancers, prompting development of antibodies to deplete them selectively.
Researchers at the University of Tokyo leveraged dogs—whose prostates closely mimic humans'—studying naturally occurring prostate cancers. They confirmed high Treg infiltration in tumors.
Using RNA sequencing and protein analysis, the team found Tregs were drawn to tumors via CCL17 binding to the CCR4 receptor.
They tested mogamulizumab, an antibody blocking CCR4. Treated dogs showed reduced circulating Tregs, longer survival, and minimal side effects compared to controls.
These findings offer real hope: human prostate tumors also show CCR4-expressing Tregs, and mogamulizumab is already approved for other cancers by major health authorities.
