# Carcinogenicity assessment: “modern toxicology” considerations from experience in the evaluation of a carbon nanotube

## TL;DR

This paper discusses how modern toxicology can prevent the harmful effects of nanomaterials, like carbon nanotubes, by assessing their potential to cause cancer early in development.

## Contribution

The paper highlights the successful early assessment of multi-walled carbon nanotubes for carcinogenicity, aligning with the goals of modern toxicology.

## Key findings

- Multi-walled carbon nanotubes were studied for their potential to cause mesothelioma, similar to asbestos.
- Early toxicity assessments can prevent widespread harm by informing developers and consumers before mass production.
- Modern toxicology aims to balance industrial growth with public safety through early communication of toxicity data.

## Abstract

The novel properties and functions of nanomaterials have naturally alerted toxicologists to the fact that such materials may also have novel effects on the human body and other living organisms. In particular, materials with high stability or biopersistency have been shown to have a tendency to accumulate in the body, leading to chronic toxicity including carcinogenicity. However, in the early stages of toxicity research, the information is often limited to the effects of short-term exposure studies, and findings on chronic effects are very much delayed. In this context, it was exceptional that studies on multi-walled carbon nanotubes (MWCNTs) have started with the verification of their potential to induce mesothelioma. This toxicological endpoint was expected on the basis of existing knowledge of asbestos and asbestos-like fiber particles. This movement has led to the achievement of the original mission of “modern toxicology,” which is “to achieve a win-win situation where both industrial promotion and safety assurance are ensured by communicating and sharing toxicity information to developers and consumers at a stage before mass production and consumption begins, that is, before massive exposure of the general public begins.”

Inaccurate toxicity assessments of asbestos in the 1980s and 1990s allowed its spread to our living environment, which is difficult to decontaminate, and the damage continues to this day. However, the case described here could be an example of realizing the proposition that “nanomaterials, the flagship of high technology, must not repeat the same mistakes.”

Key points

What is already known on this topic: The toxicity of biopersistent particles, particulate matter, and fiber particles, especially asbestos, are known to some extent.

What this study adds: MWCNTs have been effectively assessed for their toxicity, particularly their carcinogenicity.

How this study might affect research, practice, or policy: The author proposes that toxicology is made of 2 elements, “modern toxicology” and “poison science.” The win-win situation for industry and consumers, in which both industrial promotion and safety assurance are ensured, can be effectively achieved by proper use of these 2 elements.