What is the first stage of tumor development?

The first stage of tumor development is initiation. This phase involves the genetic alteration of a cell that leads to changes in its normal growth and regulatory processes. During initiation, carcinogenic factors such as chemical agents, radiation, or viruses interact with the cell's DNA, causing mutations. These mutations can disrupt normal cellular functions, which may eventually set the stage for further development of cancer.

Successful initiation does not immediately result in cancer but lays the groundwork for subsequent stages, such as promotion and progression. During these later stages, initiated cells may proliferate and form tumors, but it is the initiation stage where the critical first change occurs that may lead to tumor formation. Understanding this initial step is crucial in the context of cancer prevention and treatment strategies.