Higher concentrations of phthalates associated with breast cancer, study

Phthalates are a family of compounds; some of which are used in fragrances and nail varnishes as well as being incorporated into some food packaging.

The compounds have come under significant criticism of late as some research has pointed to their potential endocrine disrupting properties (potential to affect the hormone system).

This recent study, involving a population of 454 Mexican women (233 breast cancer cases and 221 controls), points to a correlation between the concentrations of certain phthalate metabolites in the urine and breast cancer incidences.

Monoethyl phthalate (MEP), which is a metabolite of diethyl phthalate (DEP), was found in higher concentrations in the cases than in the controls, according to the study recently published in the Environmental Health Perspectives journal.

The authors suggest that this could be related to the ability of MEP and other phthalates to induce DNA damage although they said more research was needed to fully characterize the genotoxic effects of phthalates on human breast cells.

However, the study also suggested a number of phthalate metabolites, including monobenzyl phthalate (MBzP) and mono(3-carboxypropyl) phthalate (MCPP), were inversely associated with breast cancer.

The researchers, led by Lizbeth López-Carrillo at Mexico’s National Institute of Public Health, suggest that this could be related the epigenetic effects of the compounds, or the ability of certain phthalate compounds to alter gene expression without altering the genetic code itself.

Correlation but not necessarily causation ​

López-Carrillo explained that these results suggest a correlation but not necessarily a causative relationship between certain phthalates and breast cancer incidences; even if breast cancer is associated with high concentrations of certain phthalates in the system, it does not mean that these compounds are responsible for the development of the cancer.

“It is not possible to establish causation with only one study done so far…we will need someone else to replicate our findings in other populations,”​ she told CosmeticsDesign.com.

López-Carrillo hopes that these preliminary findings will inform future research that will be able to help determine whether these compounds are indeed cofactors for breast cancer.

In addition, more research is needed to identify where these actually come from, argued López-Carrillo. Potential sources include cosmetics products such as deodorants and perfumes as well as plastic packaging.

Although the research took urine samples from participants before any treatment of breast cancer had started - to be sure that the treatment was not the cause of any elevated levels, only one sample was taken from each study participant which does not allow for any information on changes to exposure over time.

This is one of the major limitations of the study, according to the authors, and further studies are needed to characterize the magnitude and profile of phthalate exposure.

Source: Environmental Health Perspectives Journal​
doi: 10.1289/ehp.0901091
Exposure to Phthalates and Breast Cancer Risk in Northern Mexico​
​Lizbeth López-Carrillo, Raúl U. Hernández-Ramírez, Antonia M. Calafat, Luisa Torres-Sánchez, Marcia Galván-Portillo, Larry L. Needham, Rubén Ruiz-Ramos, Mariano E. Cebrián