May Metastasize Carcinogenesis Carcinogenesis is the process by which a normal cell undergoes malignant transformation. It is generally accepted that malignant transformation is a multi-step process. It involves multiple, cumulative alterations to the cell's DNA leading to genetic damage. Most human tumors are monoclonal. Monoclonal means that all of the cells in that patient's malignant tumor contain the same pattern of genetic damage that led to transformation.
Carcinogens are agents capable of initiating carcinogenesis.
Environmental, genetic and viral factors have been implicated as carcinogens. The role of oncogenes and tumor suppressor genes in tumor initiation are the current focus of many investigators. Oncogenes are genes within the cell that may initiate the cell's transformation from normal to malignant. Interestingly, examples of positively acting oncogenes are quite rare in human tumors. So-called tumor suppressor genes probably play a more important role.