Evaluations that were considered to be inadequate for a specific cancer type are not shown, however, these can be found here.
KC1: Is electrophilic; KC2: Is genotoxic; KC3: Alters DNA repair; KC4: Induces epigenetic alterations; KC5: Induces oxidative stress; KC6: Induces chronic inflammation; KC7: Is immunosuppressive; KC8: Modulates receptor-mediated effects; KC9: Causes immortalization; KC10: Alters cell proliferation/death (see “About” page).
The IARC Monographs Programme
The IARC Monographs programme was established in 1971 to identify environmental factors that are carcinogenic hazards to humans. These include chemicals, complex mixtures, occupational exposures, physical agents, biological agents, and lifestyle factors. An expert working group convened by the IARC Monographs programme assesses the strength of the available evidence that an agent can cause cancer in humans, based on three streams of evidence: studies with cancer end-points in humans, studies with cancer end-points in experimental animals, and studies with mechanistic end-points (in humans, humans primary cells, and experimental systems). In addition, the working group characterizes exposure to each agent.
Read more: https://monographs.iarc.who.int/
IARC MonDO database: the Encyclopaedia of Carcinogenic Hazards to Humans
The IARC Monographs Database Online (IARC MonDO) organizes information on all the agents that have been evaluated by the IARC Monographs programme. IARC MonDO allows users to search, including the overall evaluation for each agent, agent class (type) and exposure sources, evidence for cancer in humans (including by cancer type), evidence for cancer in experimental animals, and mechanistic evidence (including on the key characteristics of carcinogens). An additional database view option allows users to find information on each volume of the IARC Monographs , and includes a link to download the volumes.
A range of filters (including by IARC group and agent class) is available in a filter sidebar, on the left-hand side of the database page, that operates across the different table views. As some agents have been evaluated more than once, there is also an option to restrict the database search results to the most recent evaluation for each agent. Note that this option has been applied automatically to the human cancer, animal cancer, and mechanistic section tables, because the database has been populated with this information only for the latest evaluation of each agent. The “Reset all filters” option can be used to restore the full list of all agents. The “Reset column filters” option can be used to clear restrictions based on the text search options above each column.
The data from the database, after applying the selected filters, can be downloaded into CSV, XLSX, or PDF format.
Data Visualization
The data visualization section allows users to create customizable charts and to download the List of classifications by cancer site. Soon users will be able to use more customizable options for charts and heat maps and will be able to download reports for each agent according to overall evaluation, agent class, or evidence stream.
Copyright Notice
Information on copyright can be found here: https://www.iarc.who.int/copyright-notice/
Preamble to the IARC Monographs
The Preamble to the IARC Monographs describes the objectives and scope of the programme, the scientific principles and procedures used in developing a monograph, the types of evidence considered, and the scientific criteria that guide the evaluations. The Preamble should be consulted when exploring the database or reading a list of evaluations or monograph.
The current Preamble was adopted in 2019 and applies from Volume 124 onwards. Previous versions of the Preamble can be found here: https://monographs.iarc.who.int/previous-preamble/
IARC Group
In the IARC Monographs evaluation process, each agent is assigned to one of four groups ( “Classification group” ). For agents evaluated from Volume 124 onwards (under the most recent Preamble), the following Table 1 provides guidance on the possible combinations of evidence required for an agent to be assigned to a particular evaluation group.
Table 1. Combinations of evidence required for an agent to be assigned to a particular IARC Group
| Evaluation (IARC Group) | Evidence for cancer in humans | Evidence for cancer in experimental animals | Mechanistic evidence |
|---|---|---|---|
|
Carcinogenic to humans
(Group 1) |
Sufficient | Irrelevant | Irrelevant |
| Limited or inadequate | Sufficient | Strong (exposed humans) | |
|
Probably carcinogenic to humans
(Group 2A) |
Limited | Sufficient | Limited or inadequate |
| Limited | Limited or inadequate | Strong | |
| Inadequate | Sufficient | Strong (human cells or tissues) | |
| Limited or inadequate | Irrelevant | Strong (mechanistic class) | |
|
Possibly carcinogenic to humans
(Group 2B) |
Limited | Limited or inadequate | Limited or inadequate |
| Inadequate | Sufficient | Limited or inadequate | |
| Inadequate | Limited or inadequate | Strong | |
|
Not classifiable as to its carcinogenicity to humans
(Group 3) |
Inadequate | Sufficient | Strong (does not operate in humans) |
| All other situations | |||
Agent Class
For the purposes of the database, each agent was assigned to at least one “Agent class” indicating the nature of the agent or exposure. These included: Biological; Chemical; Complex exposure; Dust, particle, or fibre; Metal or metalloid; Pharmaceutical; Physical agent; Occupation; or Personal habit.
Key Characteristics of Carcinogens
Since the revision to the Preamble in 2019, the mechanistic evidence for each agent has been evaluated according to the 10 key characteristics of carcinogens framework ( Smith et al., 2016 ). The evidence for each key characteristic is considered individually ( “Mechanistic KC” ) (see Table 2 below) and combined to reach an overall mechanistic evaluation ( “Mechanistic evidence” ) of strong , moderate , limited , weak , or inadequate .
Table 2. The 10 Key Characteristics of Carcinogens
| KC | Key characteristic of carcinogens |
|---|---|
| KC1 | Is electrophilic or can be metabolically activated to an electrophile |
| KC2 | Is genotoxic |
| KC3 | Alters DNA repair or causes genomic instability |
| KC4 | Induces epigenetic alterations |
| KC5 | Induces oxidative stress |
| KC6 | Induces chronic inflammation |
| KC7 | Is immunosuppressive |
| KC8 | Modulates receptor-mediated effects |
| KC9 | Causes immortalization |
| KC10 | Alters cell proliferation, cell death, or nutrient supply |
For some agents, a “Mechanistic qualifier” was applied, which indicates instances in which the overall classification was assigned using supporting evidence from mechanistic or other relevant data. This can include upgrades, downgrades, or instances where the agent was considered to be part of a mechanistic class of agents.
Funding
The IARC Monographs are supported by grants from:
- United States National Cancer Institute (since 1982)
- European Commission, Directorate-General for Employment, Social Affairs and Inclusion (since 1986, and since 2014 from the European Union Programme for Employment and Social Innovation, EaSI )
- United States National Institute of Environmental Health Sciences (since 1992).
Suggested citation
IARC (2026). IARC MonDO (IARC Monographs Database Online). Version 20260709 [online database]. Lyon, France: International Agency for Research on Cancer. Available from: https://mondo.iarc.who.int/ .
Disclaimer
This is a preliminary version of the database, which will be updated and optimized regularly. Although great care is taken, mistakes may be present. If you find an error, or would like to share your feedback and suggestions, please contact us at imo@iarc.who.int .
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