# Plaaben Compounds--Part I: An Overview of Their Characteristics, Detection, and Impacts
## 3 Paraben Potential Impacts
### Human Health Impact
[PERSON] and [PERSON] [55] reported immediate reactions caused by parabens, in 5 of 37 patients with recurrent urticaria treated with 100 mg of MP and PP each on the first day, and a tablet containing 150 mg of each on day two [19]. Several cosmetics or medications containing parabens have already been implicated in the cause of contact sensitization, specifically dermatitis or urticaria [19]. Some members of the scientific community report the use of synthetic estrogens in the prenatal period as a cause of neurological defects, appearance of tumors or abnormalities in the immune system in the adult life [19]. A decrease in the count of male sperm has been linked to the use of estrogens or estrogen-like compounds in embryonic, fetal, and early postnatal development [19]. [PERSON] et al. [28] detected parabens at an average value of 20.6 ng/g tissue in a small number of breast tumor tissues, indicating that the presence of parabens can help to the increasing in incidence of breast cancer in women. The parabens found were MP (about 60% of total parabens), EP, n-PP, n-BuP and iso-butylparaben [19; 28]. However, some criticisms were make about this study, since there is a lack of information and missing data such as a clear link between the parabens and cancer, the route of entry of parabens, the background of patients, lack of information of the location and type of tumor, the fact that the study only used 24 patients, the use of cosmetics, absence of control tissue, etc. [20]. Another review article provided by _[PERSON] and [PERSON], 2008_ repeated the arguments that have been refuted and new data or evidence were not added [20]. A study provided by [PERSON] et al. (2012) [56] showed that in different regions of healthy breast tissue, the concentration of different parabens was similar in different breast regions, except for PP, which was detected at higher levels in the upper outer quadrant of the breast. In 40 patients that participated in the study, seven of them had never used deodorants or other products for the underarm. This study also concludes that there are no correlations between paraben concentrations and age of patient, length of breast feeding, tumor location or tumor oestrogen receptor content [20; 56]. The study of [PERSON] [57] shows that people diagnosed with breast cancer at an early age used more antiperspirant products, and another study relative to the use of these products ran by [PERSON] et al. [58] did not shown difference between the control group and a group of patients diagnosed with breast cancer [33]. An article published by [PERSON] and [PERSON] [59], as other studies already mentioned, suggests that there is not enough scientific evidence that can justify the formation of breast cancer caused by parabens. However, a study by [PERSON] et al. [60] demonstrates in vitro that parabens can induce a transformed phenotype in human breast epithelial cells (MCF-10A), which is an approved model of carcinogenesis in vitro, and [PERSON] and [PERSON] et al. [61] proved that parabens cause an increase in estradiol secreting and aromatase activity, stimulating the proliferation of human breast cancer cells (MCF-7) [62]. So, although there is a lack of solid data that can prove the increase in breast cancer caused by parabens, it seems that some in vitro studies have started to verify that parabens can interact negatively with some body functions or cells, which could lead to the formation of cancer. However, solid data in vivo have not been discovered yet by the scientific community. A study carried out by [PERSON] et al. [63] on 128 female Japanese university students found a possible relation of a decrease in menstrual cycle length and high urinary paraben concentrations. This and other studies can suggest a correlation between parabens and environmental causes of human infertility.