Cancer Biology and Therapeutic Oncology

The concept of cancer “etiology” seems inadequate, a minimum of in its classical use within the pathology of infectious, parasitic, nutrition, metabolic diseases. We consider the use of the terms carcinogenesis, cancer inducing factors or carcinogenic factors more adequate for what happens during tumor cell transformation, with the mention that the term carcinogenesis defines the initiation of a tumor, and oncogenesis its maintenance and subsequent evolution.

Tumors develop in those tissues during which cellular homeostasis has been disturbed by hyperplastic, dysplastic or regenerative changes. Clinical and experimental data have proved that in the division process the cell is more vulnerable to carcinogenic factors than at rest. Human and veterinary oncology can provide such examples: hyperplastic endometrial and mammary processes that are submitted to hormonal fluctuations represent the standard background for the looks of cancer; bronchial carcinoma in smokers invariably appears against a dysplastic or metaplasic background of the airways; bone cancer usually occurs at a young age, when physiological osteogenesis is active. These examples demonstrate that the oncogenic process is more frequent in tissues with increased cellular activity..