Bakterien in Tumoren unterdrücken die Immunantwort und fördern so die Immuntherapieresistenz. Kopf- und Halskrebspatienten mit hohen Tumorbakterienwerten hatten mit der Immuntherapie schlechtere Ergebnisse im Vergleich zur Standard-Radiochemotherapie.

Bacteria Inside Tumors Drive Immunotherapy Resistance

New research reveals that **bacteria inside tumors suppress the immune response, driving immunotherapy resistance.**

Cleveland Clinic researchers have discovered that bacteria inside cancerous tumors may be key to understanding why immunotherapy works for some patients but not others.

Two new studies, published simultaneously in Nature Cancer, reveal that elevated levels of bacteria in the tumor microenvironment suppress immune response, driving resistance to immunotherapy in patients with head and neck squamous cell carcinoma.

In the second paper, Dr. Chan led a data analysis of the Javelin HN100 Phase III clinical trial, which tested whether adding anti-PDL1 immunotherapy to standard chemoradiotherapy improved outcomes for **patients with head and neck squamous cell carcinoma. The analysis confirmed that patients with high tumor bacteria levels had poorer outcomes with immunotherapy compared to standard chemoradiotherapy**. The trial included collaborators from Memorial Sloan Kettering Cancer Center and Dana-Farber Cancer Institute.

Together, the two studies showed that elevated bacteria levels in tumors attract neutrophils, white blood cells that fight infection. While neutrophils are essential for combating bacterial infections, in cancer they can suppress the immune system needed for immunotherapy to work effectively. These findings lay the foundation for future research on why bacteria are attracted to tumors and how to modify them to improve treatment.

From the news release:

https://www.technologynetworks.com/tn/news/bacteria-inside-tumors-drive-immunotherapy-resistance-408277