Oral Bacteria Predict Kaposi's Sarcoma Progression in HIV Patients

Kaposi's sarcoma (KS) remains a major cancer burden among HIV patients, particularly in sub-Saharan Africa where both viruses are endemic. While previous research linked oral microbiomes to KS development, their role in disease progression remained unclear until this groundbreaking study.

Researchers analyzed microbiome samples from three body sites—oral cavity, blood, and tumor tissue—in 20 AIDS patients with biopsy-confirmed KS from Uganda. Half had progressive disease requiring chemotherapy, while half remained stable. Using advanced 16S rRNA sequencing, they characterized bacterial communities across these anatomical sites.

The oral cavity harbored the richest microbial diversity, with significantly more species, genera, and families than blood or tumor samples. Crucially, oral microbiome composition differed significantly between progressive and stable disease groups, while blood and tumor microbiomes showed minimal differences. Sixteen bacterial species in the oral cavity were associated with disease progression, compared to only three in tumors and one in blood.

Two key bacteria emerged as potential biomarkers: Prevotella pallens and Megasphaera micronuciformis, both producers of short-chain fatty acids (SCFAs). These bacteria were dramatically enriched in progressive disease patients. SCFAs can trigger viral reactivation and inflammation—mechanisms that could accelerate tumor growth. The researchers also identified 39 altered metabolic pathways in progressive disease, including those involved in inflammation and cellular metabolism.

These findings offer the first evidence that oral microbiome changes predict KS progression, potentially enabling earlier intervention and personalized treatment strategies for this aggressive cancer.