Types and amounts of carcinogens as potential human cancer hazards

Abstract

Current knowledge on the mechanisms of chemical carcinogenesis forms the basis for application of select short-term in vitro and in vivo tests to detect potential human carcinogens, for ultimate application to hazard assessment. Chemical carcinogenesis involves a series of distinct steps, proceeding from the initiation of a neoplastic cell, through its promotion, development, and progression to cancer. Some chemicals act in each of these stages as initiators, cocarcinogens, promoters, or inhibitors of carcinogenesis. Chemicals can be classified as operating by genotoxic or epigenetic mechanisms, and appropriate tests can be used to detect such properties. These abbreviated tests provide enhanced qualitative decision-making potential since they are based on mechanisms of action. Advances in molecular biology may provide additional tests to detect cancer risk. The quantitative data available from in vitro dose-response studies indicate that carcinogenic effects are dose dependent and, therefore, a threshold or no-effect level probably exists, which is low for potent carcinogens (especially genotoxins) and high for weaker ones (particularly epigenetic agents).

Solid phase microextraction, mass spectrometry and metabolomic approaches for detection of potential urinary cancer biomarkers—A powerful strategy for breast cancer diagnosis

“…Despite the global efforts to reduce the occurrence of this disease, cancer has become the leading cause of death in the last 50 years being breast cancer the most common malignancy in women and the second most common cause of cancer-related mortality [1,3]. Numerous risk factors for breast cancer have been identified, such as hormone-related, and the only well-established diet-related risk factors: obesity and alcohol consumption [2,4,5]. Other factors include inheritance of high-penetrance susceptibility genes, increasing age, exposure to ionizing radiation, family history of breast cancer, higher socioeconomic status, and prior benign breast disease [6].…”

Thresholds for DNA-Reactive (Genotoxic) Organic Carcinogens

“…The cancer risk from very low level exposures, i.e. less than 1.5 µg per person per day, has not been established 87,88 , in spite of the general assumption that DNA-reactive carcinogens have no thresholds and pose a risk at any level. The research reviewed here argues against that assumption.…”