Search

Evaluation of carcinogenic substances from the environment is a challenge for scientists. Recently, a novel approach based on 10 key characteristics of human carcinogens classified by the International Agency for Research on Cancer (IARC) has emerged. Carcinogenesis depends on different mechanisms and factors, including genetic, infectious (bacteria, viruses) and environmental (chemicals) factors. Endocrine disruptors are exogenous chemicals that can interfere and impair the function of the endocrine system due to their interaction with estrogen receptors or their estrogen signaling pathways inducing adverse effects in the normal mammary development, originating cancer. They are heterogeneous chemicals and include numerous synthetic substances used worldwide in agriculture, industry and consumer products. The most common are plasticizers, such as bisphenol A (BPA), pesticides, such as dichlorodiphenyltrichloroethane, and polychlorinated biphenyls (PCBs). Xenoestrogens appear to serve an important role in the increased incidence of breast cancer in the United States and numerous other countries. Several studies have demonstrated the role of organochlorine xenoestrogens in breast cancer. Therefore, the overall cumulative exposure of women to estrogens results in an increased risk for this type of cancer. Factors like lifestyle and diet also serve a role in the increased incidence of this disease. The aim of the present study was to analyze these chemical compounds based on the key characteristics given by the IARC, with a special focus on breast cancer, to establish whether these compounds are carcinogens, and to create a model for future analysis of other endocrine disruptors.

Breast cancer, the most common neoplasm in women of all ages, is the leading cause of cancer-related mortality in women worldwide. Markers to help to predict the risk of progression and ultimately provide non-surgical treatment options would be of great benefit. At present, there are no available molecular markers to predict the risk of carcinoma in situ progression to invasive cancer; therefore, all women diagnosed with this type of malignancy must undergo surgery. Breast cancer is a heterogeneous complex disease, and different patients respond differently to different treatments. In breast cancer, analysis using immunohistochemical markers remains an essential component of routine pathological examinations, and plays an import role in the management of the disease by providing diagnostic and prognostic strategies. The aim of the present study was to identify a marker that can be used as a prognostic tool for breast cancer. For this purpose, we firstly used an established breast cancer model. MCF-10F, a spontaneously immortalized breast epithelial cell line was transformed by exposure to estrogen and radiation. MCF-10F cells were exposed to low doses of high linear energy transfer (LET) α particles (150 keV/μm) of radiation, and subsequently cultured in the presence of 17β-estradiol. Three cell lines were used: i) MCF-10F cells as a control; ii) Alpha5 cells, a malignant and tumorigenic cell line; and iii) Tumor2 cells derived from Alpha5 cells injected into nude mice. Secondly, we also used normal, benign and malignant breast specimens obtained from biopsies. The results revealed that the MCF-10F cells were negative for c-Ha-Ras protein expression; however, the Alpha5 and Tumor2 cell lines were positive for c-Ha-Ras protein expression. The malignant breast samples were also strongly positive for c-Ha-Ras expression. The findings of our study indicate that c-Ha-Ras protein expression may be used as a marker to predict the progression of breast cancer; this marker may also ultimately provide non-surgical treatment options for patients who are at a lower risk.

Cervical cancer is the second most prevalent female cancer worldwide. The majority of cases appear between the age of 30 and 50. Human papillomavirus (HPV) plays a central role in cervical cancer with 99.7% of HPV DNA identified in invasive cervical carcinomas. The prevalence of the HPV infection varies substantially among countries and according to age and lifestyle. HPV is a common sexually transmitted infection among males and females with a 70% higher incidence in sexually active females. This study aimed to determine the prevalence of human papillomavirus in young university women by analyzing the correlation between Papanicolaou (PAP)-stained cervical tests and HPV detection by genotyping, as well as other risk factors. A total of 200 women aged between 18 and 25 years were enrolled in this study, which took place between September 2008 and May 2009 at the Universidad de Tarapacá, Arica, Chile. Results of the PAP smears showed that 97.5% of cells had normal characteristics, although an inflammatory pattern was noted. The prevalence of generic HPV infection was 3.5% when testing for HPV DNA using the polymerase chain reaction (PCR) method. An analysis of the genotype of infected female individuals indicated that high-risk HPV types, such as HPV 16 and 31 were present in 42.84 and 14.29% of females, respectively, and low-risk types such as HPV 6, in 14.29%. Only one sample with differentiated non-HPV (14.29%) was found. A 95% correlation between PAP-stained cervical tests and the method of testing for HPV was observed. Using the PCR method, it was found that of the 195 negative PAP smears, 5 were positive for HPV and two of the samples that were positive for ASC-US were also positive. A significantly increased (P

Breast cancer is a common disease estimated to occur in 1 in 9 women over their lifetime. Epidemiological research has identified a number of risk factors for breast cancer. Racial and ethnic differences in breast cancer mortality rates have been difficult to ascertain. The present review reports that there was an increase in the incidence of breast cancer in Arica, Chile, from 1997 to 2007, particularly in 2005, reaching 55.1% per 100,000 women, while the percentage decreased in 2006 and 2007. A greater percentage of breast cancer was found in individuals between 46 and 65 years of age when the population was distributed by age. The Indian population, Aymara, had only a 13.9% incidence of the disease. The incidence for breast cancer for patients with no family background reached approximately 88%, with or without Indian ethnicity, and 98.4% of these women did not have prior hormonal therapy. When the stage of the disease and the number of pregnancies were considered, results showed that there was an increase in the progression of the disease from stage I to stage III in women that had 1-3 pregnancies. Results also showed that 20.9 and 33.2% who received prior tamoxifen treatment were in stages I and IIA, respectively. The breast cancer incidence reached 42.4% when patients had a sister with the disease. It can be concluded that important differences in the risk factors of breast cancer should be identified in the future for a comparison with other biological factors, such as genetic and molecular factors. This may provide greater insight into breast cancer aetiology in different populations.

Breast cancer, the most common spontaneous malignancy diagnosed in women, is a classical model of hormone dependency as it is associated with prolonged exposure to female hormones. Different cytoplasmic proteins are important in the transformation of a normal cell to an invasive tumor cell, and these include vimentin and Notch. To investigate the importance of these two genes and proteins in breast carcinogenesis, we used an in vitro breast cancer model system, in which an immortalized human breast epithelial cell line, MCF-10F, was malignantly transformed by exposure to low doses of high linear energy transfer α particle (150 keV/μm) radiation and subsequent growth in the presence or absence of 17β-estradiol. This model consisted of human breast epithelial cells in different stages of transformation: i) a parental cell line (MCF-10F), ii) an Estrogen cell line (MCF-l0F continuously grown with estradiol at 10-8), iii)malignant and non-tumorigenic cell line (Alpha3), iv)malignant and tumorigenic cell line (Alpha5) and v) a Tumor2 cell line derived from a xenograft of the Alpha5 cell line injected into nude mice. Vimentin and Notch showed greater expression in the Alpha5 and Tumor2 cell lines compared with that in the non-tumorigenic cell lines, MCF-10F, Estrogen and Alpha3. In the present study, positive staining for vimentin was found in 21% of cases. Vimentin and Notch protein expression was negative in noninvasive ductal carcinoma biopsies from breast cancer patients. However, positive cell expression was observed in invasive ductal carcinoma biopsies. These biomarkers can be considered important indicators of breast cancer progression and can be added to the diagnostic panel when overall survival is a primary end-point.

The present study analyzed the risk of skin cancer due to ultraviolet erythemal irradiance (UVery) in Arica, Chile, using measurements of the solar ultraviolet index (UVI) between 2006 and 2011. The daily maximum value by biometer Yankee Environmental Systems (YES) solar ultraviolet B (UVB)-1 was measured between 2007 and 2012, and seasonal variations were clearly observed, with higher UVI levels during the summer when UVI usually reached extreme values of >11. The maximum UVI value was 15.6 in the summer of 2008 and the minimum was 2.2 in the winter of 2008. The UVI mean values that were collected monthly at noon between 2006 and 2010 fluctuated between 13 and 6, and reached higher values in January and lower values in June and July. Thus, a seasonal UVI response was observed during the two seasons. The accumulated UVery/day was calculated between September 2006 and 2007, the time when Arica normally receives the highest UVI levels. It was also noted that 60% of the days in September demonstrated values of >3.41 kJ/m2/day, while 3.3% of cloudy days had values of

An increase in the amount of solar ultraviolet light that reaches the Earth is considered to be responsible for the worldwide increase in skin cancer. It has been reported that exposure to excessive levels of solar ultraviolet light has multiple effects, which can be harmful to humans. Experimental ultraviolet light measurements were obtained in several locations in Chile between 2006 and 2009 using wide-band solar light Biometer YES, calibrated according to World Meteorological Organization (WMO) criteria and integrated into the National Meteorological Center of Chile ultraviolet network (DMC). The aim of this study was to determine skin cancer rates in relation to experimental data accumulated during one year of studying the solar ultraviolet index in Chile, in order to explain the possible effect of radiation on skin cancer. The rate of skin cancer per 100,000 persons was considered in Arica, Santiago, Concepcion and Valdivia and extrapolated to other cities. Results of the present study showed that the incidence of skin cancer was markedly correlated with accumulative ultraviolet radiation, and rates of skin cancer could be extrapolated to other locations in Chile. There is a steady increase in the rate of skin cancer in cities located nearest to the equator (low latitude) that receive greater accumulated solar ultraviolet radiation, due to the accumulative effects of this type of radiation on the skin. It can be concluded that Arica is a city at sea level that receives higher levels of ultraviolet solar radiation than other locations, which may explain the higher prevalence of skin cancer in the population of this location, compared with other cities in Chile.