Researchers have revealed how cervical and throat cancers linked to human papillomavirus (HPV) evade the immune system, paving the way for new treatments. According to new research, the most common cancer-causing strain, HPV 16, undermines the body’s defenses by reprogramming immune cells surrounding the tumor. Inhibiting this process in mice enhanced the effectiveness of experimental HPV treatments in eradicating cancer cells. The study, conducted by researchers at the Keck School of Medicine at the University of Southern California and published in the Journal for ImmunoTherapy of Cancer on August 19, explains that HPV 16 causes over half of cervical cancer cases and about 90% of HPV-related throat cancers. While the preventive Gardasil-9 vaccine can neutralize the virus if administered before exposure, therapeutic vaccines are being developed to stimulate immune responses after infection or abnormal cervical screening results.

The research focuses on the immune signaling protein interleukin-23 (IL-23), known for its role in chronic inflammatory diseases and involvement in cervical and throat cancers. Experiments showed that HPV proteins E6 and E7 induce nearby cells to release IL-23, which inhibits T cells from attacking tumors. Dr. W. Martin Kast, co-author and head of cancer research at Keck, stated, ‘To eliminate cancer, T cells need to proliferate and destroy infected cells, but IL-23 protein prevents them from functioning effectively, allowing tumor growth to continue.’ The study found that blocking IL-23 increased the efficacy of therapeutic HPV vaccines by enabling T cells to detect and destroy cancer.