Mutagenicity monitoring in humans: Global versus specific origin of mutations.

An underappreciated aspect of human mutagenicity biomonitoring is tissue specificity reflected in different assays, especially those that measure events that can only occur in developing bone marrow (BM) cells. Reviewed here are 9 currently-employed human mutagenicity biomonitoring assays. Several assays measure chromosome-level events in circulating T-lymphocytes (T-cells), i.

Do chromosome changes in blood cells implicate formaldehyde as a leukemogen?

Formaldehyde (FA) is a mutagenic chemical - a property mitigated in vivo by rapid detoxification and limited tissue distribution following inhalation of the free agent. Endogenously produced FA is necessary for life and required for one-carbon transfer reactions; however, FA derived from external sources (exogenous FA), which may be in the form of methanol, may increase in vivo concentrations above naturally occurring physiological levels. Both endogenous and exogenous FA produce DNA monoadducts, DNA-DNA and DNA-protein cross-links (DDX and DPX) but, when exposed to exogenously-derived free FA, DNA monoadducts, DDX, and DPX are only produced at initial sites of contact.

The bone marrow niche, stem cells, and leukemia: impact of drugs, chemicals, and the environment.

Hematopoietic stem cells (HSCs) are a unique population of somatic stem cells that can both self-renew for long-term reconstitution of HSCs and differentiate into hematopoietic progenitor cells (HPCs), which in turn give rise, in a hierarchical manner, to the entire myeloid and lymphoid lineages. The differentiation and maturation of these lineages occurs in the bone marrow (BM) niche, a microenvironment that regulates self-renewal, survival, differentiation, and proliferation, with interactions among signaling pathways in the HSCs and the niche required to establish and maintain homeostasis. The accumulation of genetic mutations and cytogenetic abnormalities within cells of the partially differentiated myeloid lineage, particularly as a result of exposure to benzene or cytotoxic anticancer drugs, can give rise to malignancies like acute myeloid leukemia and myelodysplastic syndrome.

Benzene 2009--Health effects and mechanisms of bone marrow toxicity: implications for t-AML and the mode of action framework.

This overview of the Symposium and its organization includes a historical survey of the scientific literature in which the relationship of benzene exposure to the development of aplastic anemia and other bone marrow diseases, including acute myeloid (myelogenous) leukemia, is described. Previous conferences on the health effects of benzene are summarized. The important role of the revised World Health Organization classification of tumors of the hematopoietic and lymphoid tissues in clarifying the specific diseases related to benzene exposure is emphasized.