Genetic toxicology – Kristian Dreij's group

Our research focuses on understanding how complex chemical mixtures in environmental pollution contribute to cancer and related diseases. We investigate the underlying mechanisms of mixture toxicity to enhance the scientific basis for health risk assessment and improve public health protection.

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News and updates

New publication!

In the review Integrating liquid biopsy and mutational signatures to advance precision oncology, we discuss the integration of liquid biopsy and mutational signatures as a potential framework to address current limitations in precision oncology by enabling longitudinal detection of mutational processes that arise during tumor development and evolution.

Cite this article: 

Carrasco, R., Dreij, K. Integrating liquid biopsy and mutational signatures to advance precision oncology. npj Precis. Onc. (2026). https://doi.org/10.1038/s41698-026-01337-w 
 

Mixed pollutants have a worsened effect
Fire in Amazonas Photo: Getty Images
Kristian Dreij's group

Mixed pollutants have a worsened effect

12-06-2025 11:09

One plus one does not equal two - it is more. Researchers have developed a method to analyse the toxic effects of mixed air pollutants. The method reveals greater health damage from poor air quality than analyses of individual substances suggest.

Felipe de Oliveira Galvão awarded the Sten Orrenius Prize
Photo: Anna Persson
Kristian Dreij's group

Felipe de Oliveira Galvão awarded the Sten Orrenius Prize

22-01-2025 11:25

Research Specialist Felipe de Oliveira Galvão receives the Sten Orrenius Prize 2024 for best original article by an early career scientist in the field of toxicology.

Air pollution from biomass burning has a high cancer potency
Photo: Pixabay
Kristian Dreij's group

Air pollution from biomass burning has a high cancer potency

16-09-2024 12:58

In a new study from the Institute of Environmental Medicine (IMM), an alternative method for assessing the cancer potency of air pollution is presented, focusing on mixtures of organic pollutants in particles.

What we do

Dreij's lab aims to shift the focus from studying the toxic effects of single chemicals to understanding the effects of complex mixtures found in our environment. Our research investigates toxicity in exposed populations, and on human cells and zebrafish using environmental samples, allowing us to identify mechanisms of mixture toxicity and improve health risk assessment of environmental pollution. 

Current projects focus on air pollution in urban and rural environments, and past projects have included research on mixture effects associated with contaminated soils (Environ Sci Technol 2015, Environ Res 2020), indoor air quality in preschools (Sci Total Environ 2021), and occupational exposure to pesticides and genotoxicity in Bolivian populations (Sci Total Environ 2019, J Expo Sci Environ Epidemiol 2020). 

We also investigate the effects of genotoxic chemicals and mixtures on transcription and replication fidelity by studying RNA and DNA mutagenesis (NAR 2017, PNAS 2018).

Current projects

Development of new approach methodologies for assessing cancer risks associated with air pollution mixtures
Current strategies for cancer risk assessment (CRA) of air pollution are today based on a pollutant-by-pollutant approach. This is a great simplification and excludes the possibility of mixture effects that may underestimate actual human health risks. The aim of this project is to address these issues by developing a New Approach Method (NAM) for CRA of air pollution mixtures. We propose that CRA of complex mixtures should be based on in vitro toxicity testing of whole mixtures and determination of relative Mixture Potency Factors (MPFs) (Toxicology 2014). We have previously shown that this approach can accurately determine the genotoxic potency of individual air pollutants (Environ Sci Technol 2017). Using this NAM, we aim to show that CRA of air pollution based on in vitro MPFs better predict the lung cancer risk associated with exposure to ambient air PM than currently accepted component-based approaches. We are now applying this NAM with samples representing different emission sources and environments (Environ Int 2022, 2024). This project is funded by the Swedish Research Council FORMAS, STINT/CAPES, and Karolinska Institutet. PI: Kristian Dreij

 

Mutational signatures of environmental complex mixtures
Experimentally determined mutational signatures have provided important insights into the agents and processes that cause of human cancer. Although humans mainly are exposed to complex mixtures of agents that may contribute to carcinogenesis, this research has focused exclusively on single mutagens. The overall objective of this project is to determine mutational signatures induced by complex environmental mixtures in human cells, thereby improving the understanding of the mechanisms and the role of mixtures versus single agents in cancer etiology. This project is funded by the Swedish Research Council VR and Karolinska Institutet. PI: Kristian Dreij

 

Assessment of acute respiratory and cardiovascular health effects due to biomass smoke exposure in the Brazilian Amazon
Biomass burning is a global concern in terms of climate change, biodiversity, and health risks. Worldwide, approximately 3 billion people are exposed to biomass particulate matter (PM). Biomarkers of exposure and effect are fundamental for understanding environmental exposures, mechanistic pathways, and monitoring early adverse outcomes. Our goal is to assess the acute cardiopulmonary health effects of short-term exposure to biomass PM among the population in the Amazon deforestation arc, together with in vitro analyses of sampled PM in a lung cell model to provide a mechanistic characterization of the health hazard. This project will be the first of its kind to combine personal exposure monitoring, specific cardiopulmonary biomarkers, and functional testing with mechanistic in vitro studies of collected PM in the Amazon.  This project is funded by the Swedish Research Council FORMAS and Karolinska Institutet. PI: Felipe de Oliveira Galvão

Publications

Selected publications

Funding

Grants

  • Swedish Research Council
    1 January 2023 - 31 December 2026
    Vital knowledge has been gained from studying driver mutations of cancer, but a few mutations in a limited number of genes cannot fully describe the complexity of carcinogenesis. The recent development of NGS has enabled the identification of genome wide mutational signatures and provided important insights into the underlying causes of human cancer. Although humans mainly are exposed to complex mixtures of agents contributing to cancer development, like air pollution and lung cancer, this research has entirely focused on single mutagens, which likely has impeded the application of mutational signatures in cancer research. The public health impact of understanding these associations is significant
    identifying causes of cancer is essential for effective preventative interventions. Here, the aim is to determine mutational signatures of environmental complex mixtures using urban air PM samples and normal lung and liver cells. Mutational signatures will be determined by whole genome sequencing followed by somatic variant-calling, and the air PM samples have been collected in three cities differently impacted by emission sources. The signatures will be functionally validated by transcriptome gene expression analysis and association analyses between enriched pathways and mutational signatures. The proposed project comprises a novel approach by combining advanced NGS technology and environmental samples to establish the mutagenic impact of complex mixtures in cancer development.
  • Swedish Research Council for Environment Agricultural Sciences and Spatial Planning
    1 January 2023 - 31 December 2026
    Biomass burning is a global concern in terms of climate change, biological diversity, and health hazards. Globally, ca 3 billion people are exposed to biomass particulate matter (PM). Biomarkers of exposure and effect are fundamental for understanding environmental exposures, mechanistic pathways, and monitoring early adverse outcomes. Our aim is to assess the acute cardiopulmonary (CP) health effects due to short-term exposure to biomass PM among the population in Amazon deforestation arc together with in vitro analyses of sampled PM in a lung cell model to provide a mechanistic characterization of the health hazard. The project is based on a panel study in Amazon, with measurements of CP health and effect biomarkers using an exposure lag of 1-7 days during the wet and dry season with exposure assessment based on personal PM monitoring and urinary metabolites. The mode of action is assessed by in vitro studies using sampled PM. The project addresses the so far neglected and less understood issue of acute CP effects due to short-term exposure to PM from wildfires. This project will be the first of its kind to combine personal monitoring of exposure, specific CP biomarkers, and functional tests with mechanistic in vitro studies of collected PM in Amazon. How does this translate to public awareness? To reduce the gap between high-quality research and effectively engaging affected communities we will use environmental education strategies among the exposed population.
  • Swedish Research Council for Environment Agricultural Sciences and Spatial Planning
    1 January 2020 - 31 December 2022
  • Swedish Foundation for International Cooperation in Research and Higher Education
    1 January 2020 - 1 January 2023
  • Swedish Research Council
    1 January 2018 - 31 December 2021

Staff and contact

Group leader

All members of the group

Visiting address

Karolinska Institutet, Institute of Environmental Medicine, Nobels väg 13, 3rd floor, Stockholm, 17177, Sweden

Postal address

Karolinska Institutet, Institute of Environmental Medicine, Box 210, Stockholm, 17177, Sweden

Keywords:
Air Pollution Analytical Chemistry Biochemistry Biomass Cardiology and Cardiovascular Disease Show all
Content reviewer:
Kristian Dreij
Kristian Dreij
09-03-2026