Cell-to-Cell Communication: Relationship of Stem Cells to the CarcinogenicProcess

摘要

That rather self-serving quotation from Albert Szent-Gyorgyi was chosen tohighlight this brief analysis of the problem of understanding the elements of a biologically based cancer risk-assessment model. It should go without saying that understanding all the mechanisms related to multistep carcinogenesis is not an easy task. The known complex interactions of genetic, developmental, sex, dietary, and environmental factors in carcinogenesis in both laboratory animals and human beings precludes direct and easy extrapolation from controlled in vitro and experimental animal bioassay systems to the uncontrolled human situation. While recent advances in modern molecular biology related to development of the concept of oncogenes, cancer suppressor genes, experimental initiation/promotion/progression model systems, and basic studies on the control of cell growth (i.e., growth regulators and second messengers) have given us valuable information related to the cancer process, no clear picture or consensus view has emerged. For the sake of taking a different view of the information gathered, we will challenge some of the basic assumptions related to the current paradigm guiding the cancer research field, namely, 'carcinogenesis as mutagenesis'. Put succinctly, while the bulk of the molecular, biochemical, and cellular studies related to 'carcinogens' and carcinogenesis have been done on the predominate cells of target organs the target cell for carcinogenesis (i.e., the early stem or progenitor cell) has not been used.