Figure 2.

Models of carcinogenesis. In addition to the acquisition a complex array of DNA alterations proposed in the accepted model of carcinogenesis (A), the model discussed in this review (B) proposes that cancer develops an alteration in the metabolism of oxygen. Although both changes must interact for the development of cancer, the altered oxygen metabolism of tumor cells is not subject to the high genetic complexity and variability of tumors and may therefore be a more reliable target for cancer therapy.