Occupational exposure to pesticides deregulates systemic cortisol levels in women with breast cancer and correlates with poor prognosis features

Abstract

Pesticides have been pointed out as hormone disruptors and may significantly affect the prognosis of hormone-dependent diseases such as breast cancer (BC). Here, we investigated the impact of occupational pesticide exposure on systemic cortisol levels in female rural workers diagnosed with BC. Occupational exposure was assessed by interviews with a standardized questionnaire. Plasma samples (112 from pesticide-exposed women and 77 from unexposed women) were collected in the afternoon, outside the physiological cortisol peak, and analyzed by a chemiluminescent paramagnetic immunoassay for the quantitative determination of cortisol levels in serum and plasma. The results from both groups were categorized according to patients' clinicopathological and exposure data. BC pesticide-exposed women presented higher levels of cortisol than the unexposed. Higher cortisol levels were also detected in the exposed group with more aggressive disease (triple-negative BC), with tumors over 2 cm, with lymph node metastases, and with high risk of disease recurrence and death. These findings demonstrated that there is an association between pesticide exposure and BC that affected cortisol levels and correlated to poor disease prognosis.

Figure 1. Cortisol levels in plasma samples from breast cancer patients exposed or not to pesticides categorized according to their clinicopathological features. A, overall circulating levels; B, cortisol levels according to disease aggressiveness (low=luminal tumors, high=triple-negative breast cancer); C, cortisol levels according to tumor size (2 cm cut-off); D, cortisol levels according to tumor grade (low=1 and 2, high=3); and E, cortisol levels according to presence or absence of metastasis. Data are reported as violin plots. *P<0.05, Mann-Whitney's test. The dotted line represents the start of the axis (level zero).