In terms of Carcinogenesis we know that various forms of cancer may be caused by Chronic toxicity, and we also know that acute exposures can also lead to cancer. Find a toxicant that requires chronic exposure to cause cancer, and another that is driven by acute exposure. Comment on the modes of action that each of these examples you provide utilize to cause cancer (in other words, does it alter cell signaling, does it alter metabolism, DNA, RNA, Protein synthesis, etc?). For your reply choose two examples provided by your classmates postings and provide additional facts as to the exposure to toxicants and the ensuing carcinogenesis.
An example that none of you may utilize for this discussion board, and keep in mind your example should be much more detailed in it's explanation.
Example: Back in the early 1920's young highschool girls were utilized as cheap labor by watch companies to paint the numbers on the face of the watches with Radium-based paints, so that they would glow in the dark. They were told to utilize their tongue to roll the tip of the brush to a point so the numbers could be painted more precisely.
These women shortly (within 1-5 years) came down with various forms of cancers of the mouth, tounge and neck, as well as jawbone deterioration.
It is theorized that the chronic internal exposure to the radioactivity contained in the paint caused DNA damage that may have affected Damage checkpoints in the cell cycle, driving the cell to multiply much more rapidly than normal.
Bypassing through these points, and expediting their growth, the affected cells became cancer cells, eventually, becoming visible tumors. This would be an example of Chronic toxicity to radiation of the mouth.