Relevance of Carcinogen-Induced Preclinical Cancer Models

Chemical agents can cause cancer in animals by damaging their DNA, mutating their genes, and modifying their epigenetic signatures. Carcinogen-induced preclinical cancer models are useful for understanding carcinogen-induced human cancers, as they can reproduce the diversity and complexity of tumor types, as well as the interactions with the host environment. However, these models also have some drawbacks that limit their applicability and validity. For instance, some chemicals may be more effective or toxic in animals than in humans, and the tumors may differ in their genetics and phenotypes. Some chemicals may also affect normal cells and tissues, such as by causing oxidative stress, inflammation, and cell death, which may alter the tumor behavior and response to therapy. Furthermore, some chemicals may have variable effects depending on the exposure conditions, such as dose, route, and duration, as well as the animal characteristics, such as genetics and hormones. Therefore, these models should be carefully chosen, validated, and standardized, and the results should be cautiously interpreted and compared with other models. This review covers the main features of chemically induced cancer models, such as genetic and epigenetic changes, tumor environment, angiogenesis, invasion and metastasis, and immune response. We also address the pros and cons of these models and the current and future challenges for their improvement. This review offers a comprehensive overview of the state of the art of carcinogen-induced cancer models and provides new perspectives for cancer research.

Reduction of Management Costs and Avoidance of Air Release of Carcinogens Through a Waste Segregation Program in a Brazilian Medical Institution

Hospital waste management is a current sustainability challenge. Although not always performed, the most applied approach in current protocols is the proper segregation of waste. The incineration of hospital waste is an significant source of emission of specific toxic particles and gases. We highlighted dioxins, whose representatives have been considered carcinogenic agents since 1994. Several experimental and epidemiologic studies have shown greater cancer morbidity and mortality associated with dioxin exposure. In the present study, we presented the impact of a hospital waste management program implemented in an oncology institution based on proper segregation and consequent reduction of incinerated mass. Data were collected for 8 years and the waste was separated into five categories: infectious (A4), chemical (B), recyclable (DR), non-recyclable (DNR), and sharps (E). The classes addressed to incineration were A4, B, and E. A team education starting from the admission process and with a continued education program was essential for a successfully implemented program. We achieved a 66% saving of waste from incineration, equivalent to 76 tons, of which 71.9 tons corresponded to recyclable waste. If the waste separation protocol was not implemented, the biohazardous and chemical material would contaminate the rest of the residues, making incineration as a final destination mandatory for all the waste. This scenario would result in significantly more dioxins release and a 64% higher cost of waste management. This low-cost implementation measure was effective in the cost reduction of waste management and minimization of air release of human carcinogens.

Cytostatics as hazardous chemicals in healthcare workers' environment

Cytostatics not only induce significant side-effects in patients treated oncologically but also pose a threat to the health of occupationally exposed healthcare workers: pharmacists, physicians, nurses and other personnel. Since the 1970s numerous reports from various countries have documented the contamination of working areas with cytostatics and the presence of drugs/metabolites in the urine or blood of healthcare employees, which directly indicates the occurrence of occupational exposure to these drugs. In Poland the significant scale of occupational exposure to cytostatics is also confirmed by the data collected in the central register of occupational carcinogens/mutagens kept by the Nofer Institute of Occupational Medicine. The assessment of occupational exposure to cytostatics and health risks constitutes employers' obligation. Unfortunately, the assessment of occupational risk resulting from exposure to cytostatics raises a number of concerns. Provisions governing the problem of workers' health protection are not unequivocal because they derive from a variety of law areas, especially in a matter of hazard classification and safety data sheets for cytostatics. Moreover, no legally binding occupational exposure limits have been set for cytostatics or their active compounds, and analytical methods for these substances airborne and biological concentrations are lacking. Consequently, the correct assessment of occupational exposure to cytostatics, the evaluation of health hazards and the development of the proper preventive strategy appear difficult. The authors of this article described and discussed the amendments to the European provisions concerning chemicals in the light of employers' obligations in the field of employees' heath protection against the consequences of exposure to cytostatics. Some modifications aimed at a more effective health protection of workers occupationally exposed to cytostatics were also proposed. Int J Occup Med Environ Health. 2019;32(2):141-59.