Reference summary — not medical advice or a personal risk estimate.
Kaposi sarcoma-associated herpesvirus (KSHV / HHV-8)
Quick answer
Classified as Group 1 — carcinogenic to humans, based on sufficient evidence in humans. Infection. Spread mainly through saliva. Most people who carry it never develop disease; risk concentrates in people with weakened immune systems.
Summary
A herpes virus associated with Kaposi sarcoma and rare lymphomas.
Detail
KSHV (HHV-8) is Group 1 with sufficient evidence for Kaposi sarcoma, primary effusion lymphoma and multicentric Castleman disease. Most often spread through saliva; people who are immunosuppressed face the highest risk of disease.
What's not established
This classification is based on sufficient evidence in humans that this factor can cause cancer. It does not establish a safe exposure threshold, your personal risk, or how this factor's risk compares in size to other Group 1 agents — hazard classifications are not ranked by magnitude.
Regional relevance
global
Evidence sources
Every claim on this page traces back to one of these. Click through to read the primary document yourself.
Primary sources
NCI
NCI — Risk Factors: Infectious Agents
IARC
IARC Monographs — Classifications by Cancer Site, Vols 1–140
Supporting sources
ECDC
ECDC — Communicable diseases and cancer risk (European Centre for Disease Prevention and Control)
ACS
ACS — Known and Probable Human Carcinogens
Cancer Research UK
Cancer Research UK — Causes of cancer and reducing your risk
NTP
NTP — Report on Carcinogens (US National Toxicology Program)
Last reviewed: October 2026
Official reference list
A government list some readers use alongside the primary evidence. Meyron is not affiliated with it. A chemical being listed does not by itself describe a risk from any particular product.
- California Prop 65 list
State of California's list of chemicals known to cause cancer or reproductive harm.