{"id":41033,"date":"2026-02-26T00:01:16","date_gmt":"2026-02-26T05:01:16","guid":{"rendered":"https:\/\/beyondpesticides.org\/dailynewsblog\/?p=41033"},"modified":"2026-02-27T10:22:06","modified_gmt":"2026-02-27T15:22:06","slug":"women-in-agriculture-at-elevated-risk-of-more-aggressive-breast-cancer-from-pesticides-study-finds","status":"publish","type":"post","link":"https:\/\/beyondpesticides.org\/dailynewsblog\/2026\/02\/women-in-agriculture-at-elevated-risk-of-more-aggressive-breast-cancer-from-pesticides-study-finds\/","title":{"rendered":"Women in Agriculture at Elevated Risk of More Aggressive Breast Cancer from Pesticides, Study Finds"},"content":{"rendered":"

(Beyond Pesticides<\/em>, February 26, 2026) Published in PLOS ONE<\/em><\/a>, research in Brazil \u201canalyzed the impact of occupational\/household chronic exposure to pesticides on the clinicopathological profile of breast cancer in rural women from Paran\u00e1 southwest, a predominantly rural landscape with large pesticide uses,\u201d finding that \u201cpesticide exposure favors the occurrence of more aggressive breast cancer.\u201d The study highlights the disproportionate risks<\/a> of pesticides to farmworkers, focusing on women<\/a>, as it compares exposed and unexposed populations and breast cancer tumor\/disease characteristics.<\/p>\n

One of the study authors, Carolina Panis, PhD<\/a>, discussed her earlier research at the Beyond Pesticides\u2019 42nd<\/sup> National Forum Series, The Pesticide Threat to Environmental Health: Advancing Holistic Solutions Aligned with Nature<\/a>. In her previous work, Pesticide exposure and increased breast cancer risk in women population studies<\/a>, Dr. Panis documents a number of pesticides that \u201ccan increase the risk of BC [breast cancer] development through various mutagenic [genetic mutations] and nonmutagenic mechanisms and can act directly as carcinogens or indirectly as biochemical modifiers and hormonal deregulators. The underlying mechanisms include endocrine disruption<\/a>; genotoxicity<\/a>; epigenetic changes<\/a> [changes to gene function without changing DNA]; enhanced cell migration, invasion, and…\u201d more. Dr. Panis and other researchers at the Forum support community-level understanding of the science and its relationship to debilitating and deadly disease patterns associated with toxic chemical exposure, so that people close to home and around the globe can effectively advocate for the necessary changes that are within reach. (See the recording here<\/a>.)<\/p>\n

Scientific literature documents how areas with an abundance of chemical-intensive agriculture, such as Brazil, experience increased adverse health and environmental effects. As the current study states: “Despite evidence on the negative impact of pesticides on human health, the country stands out among the top three pesticide consumers globally. The implications of this scenario on rural workers health, particularly women, is completely neglected, resulting in chronic illness such as breast cancer.\u201d<\/p>\n

The authors continue, \u201cTo our knowledge, this is the first study that uses the described methodology [below] to predict the relationship of variables related to breast cancer severity in a population categorized according to their pesticide exposure profile.\u201d As a result, the research highlights the link between occupational pesticide exposure and the occurrence of breast tumors with more aggressive clinicopathological (combining clinic and laboratory) findings. This includes \u201can increased frequency of disease recurrence, chemoresistance, death, and predominance of the molecular subtype Luminal B<\/a>,\u201d an aggressive, hormone receptor-positive (HR+) type of breast cancer.<\/p>\n

Study Importance and Background<\/strong><\/p>\n

As the researchers point out, pesticide use in agriculture started with, and continues to be used, with the stated justification of increased food production for the growing world population, despite scientific literature that continues to showcase the acute and chronic consequences of their application and the availability of sustainable, productive, and profitable alternatives. Many pesticides are known endocrine disruptors<\/a>, able to \u201cinfluence the development of tumors in the female reproductive system, increase aromatase activity and estrogen production, reduce fertility, augment estrogen production, increase androgen availability, competitively bind to estrogen cell receptors, enhance proliferation of estrogen-sensitive cells, and inhibit corticosterone synthesis in the adrenal cortex.\u201d<\/p>\n

Elevated risk of pesticide-induced breast cancer is associated with \u201cvarious mutagenic and nonmutagenic mechanisms, acting either directly as carcinogens or indirectly as biochemical modifiers and hormonal disruptors,\u201d the authors state. \u201cThe underlying mechanisms include endocrine disruption, genotoxicity, epigenetic [environmentally-driven heritable changes] alterations, enhanced cell migration, invasion, and stemness, angiogenesis [forming new capillary blood vessels], and tumor growth, among others.\u201d<\/p>\n

Beyond Pesticides has extensively covered breast cancer and other common diseases, as documented in the Pesticide-Induced Diseases Database<\/a> and through the Daily News<\/em> Blog<\/a>. In an article from last year, titled Pesticides Harming Immune Cell Function Linked to Elevated Breast Cancer Rate in Young Women<\/a>, a study in Immunopharmacology and Immunotoxicology<\/em><\/a> documents elevated rates of breast cancer in women with occupational pesticide exposure. This study was also of Brazilian women who were either occupationally or domestically exposed to pesticides and includes Dr. Panis as an author. (See additional Daily News<\/em> on breast cancer here<\/a>.)<\/p>\n

In analyzing the Southeastern region of northern Paran\u00e1, Brazil in the study, the researchers reference three herbicides as the most prevalent, writing: \u201c[The study] population is subject to considerable pesticide exposure, especially glyphosate, atrazine, and 2,4-dichlorophenoxyacetic (2,4-D), which are widely used in soybean, corn, and wheat monocultures in the region… Additionally, women occupationally exposed to areas where glyphosate, atrazine, and 2,4-D are predominantly used have a higher risk of developing breast cancer.\u201d (See study here<\/a>.)<\/p>\n

The weed killer glyphosate<\/a> has long been tied to adverse effects, including endocrine disruption, one of the mechanisms that can cause breast cancer. Research shows that in breast cancer cells, glyphosate exposure \u201cleads to altered expression<\/a> of cell proliferation-related genes, and dysregulation<\/a> of key genes involved in tumor aggressiveness and metastasis [spread of cancer cells].\u201d (See Daily News<\/em> coverage on glyphosate here<\/a>.)<\/p>\n

Atrazine<\/a>, a triazine herbicide, also exhibits endocrine-disrupting effects, with studies showing impacts to mammary glands and hormone levels. (See here<\/a> and here<\/a>.) \u201cIn breast cancer cells, atrazine alters protein expression and modulates antioxidant defense gene expression, promoting genomic instability and oxidative stress<\/a>-induced damage, a recognized mechanism for breast cancer development and progression, also linked to immune deregulation in patients and inflammatory changes in normal mammary tissue in exposed women,\u201d the authors note. (See Daily News<\/em> coverage on atrazine here<\/a>.)<\/p>\n

Finally, the herbicide 2,4-D<\/a> is associated with an increased risk of cancer, particularly mesothelioma and non-Hodgkin lymphoma, and endocrine disruption, along with many other adverse health effects including neurotoxicity, reproductive dysfunction, and developmental delays. (See Daily News<\/em> coverage on 2,4-D here<\/a>.)<\/p>\n

This study highlights the growing trend of women in agriculture and the disproportionate risks they face. \u201c[I]t has been estimated that women represent 43% of the world\u2019s agricultural workforce,\u201d the researchers state. They continue: \u201cThis trend has been observed in several regions of the world, such as in the European Union, where women represent 29% of rural workers, Brazil, where they represent 45%, and certain regions of Africa and Asia, where women\u2019s representation can reach up to 60%. The feminization of agriculture may lead to an increase in the incidence of cancer in women.\u201d<\/p>\n

Methodology and Results<\/strong><\/p>\n

As a cross-sectional and quantitative exploratory study, this research uses clinicopathological data from medical records, along with interviews, to categorize women as exposed or unexposed to pesticides and analyze that relationship with breast cancer diagnoses and characteristics. The data comes from the Francisco Beltr\u00e3o Cancer Hospital, where a total of 923 women, from May 2015 to April 2023, had images suggestive of breast lesions. From that total, 349 patients were selected for study analyses after a diagnosis of breast cancer was determined by a pathologist.<\/p>\n

\u201cTo characterize exposure, we previously performed a 2-year study aiming to get detailed information about patients\u2019 exposure profile,\u201d the authors write. \u201cTo reach this goal, patients were invited to complete a comprehensive questionnaire with 61 questions covering their current and past occupational history.\u201d This led to the categorization of the study population as either occupationally exposed (n\u2009=\u2009208) or unexposed (n\u2009=\u2009141) to pesticides.<\/p>\n

The women in the exposed group \u201creported spending at least 50% of their lives working with pesticides and having direct contact with these substances at least once a week,\u201d with activities such as washing items contaminated with pesticides, preparing and diluting concentrated pesticides, and spraying diluted pesticides on crops. \u201cFurthermore, 94% of the women in the exposed group reported performing these tasks without using PPE [personal protective equipment], not even gloves,\u201d the researchers say. \u201cAs pesticides are primarily absorbed through the skin, this chronic and prolonged exposure represents a significant contamination route, surpassing potential exposure from food or water sources.\u201d<\/p>\n

Noteworthy results of the study include:<\/p>\n