Critical Reviews in Oncogenesis is dedicated to the critical analysis of selected basic aspects of oncology. It appears quarterly and contains three or more extensive articles in each issue. The main purpose of the journal is to offer readers a selection of extensive reviews on topics of current interest in the field of basic oncology. Information contained in each article represents the results of a critical analysis of many papers which are frequently dispersed in a multitude of journals with different scientific scopes. The literature related to the genetic and environmental factors involved in the origin and development of tumors has undergone an almost explosive growth in the last few years, and it is difficult to maintain a good level of information in this field. The reader finds material in the reviews which can contribute greatly to a better understanding of the complex oncogenic processes.