An external stimulus or agent that produces a cell that can become malignant under certain conditions. Initiation events may be mutational changes in a cell's genetic material, where the change is initially unexpressed and causes no detectable alteration in the cell's growth pattern. The change is considered to be irreversible. The interval between the first exposure to a carcinogenic stimulus and the appearance of a clinically diagnosable tumor. For a disease like cancer, which usually involves a sequence of steps over a long period, the term latent period may be ambiguous.
Malignant melanoma is a cancer of the cells that produce the pigment melanin.
The age at which menstruation begins. The spread of a malignancy to distant body sites by cancer cells transported in blood or lymph circulation. A substance that can alter the course of carcinogenesis. The condition of being diseased, or the incidence or prevalence of some particular disease. The morbidity rate is equivalent to the incidence rate.