Comparative Aspects of Tumor Development

of the interaction and relationship of both systems is chal- In this volume, aspects of neoplastic spread, already elu- cidated in Volumes I-IV of this series, are considered lenging indeed. against a broad biological background. The mammalian The volume also reviews environmental oncology and species-specific aspects of environmental chain reactions. It orders constituting the logical framework for man as focal point of a comparative oncology are reviewed. Selected is apparent that the environment plays a significant role in examples of neoplastic progression in various taxonomic the development of neoplasms. Neoplasms among the spe- units are provided, beginning with the opposite pole of ci es have become much more common as a result of man's taxonomic development, the vascular plants, where no impact on the environment. The latter chapters present a metastatis of malignant neoplasms occur. Among in- brief review of geologic and technologic and cuItural vertebrates, vertebrates, and vascular plants, Iining mem- changes, and the implications of species-specific cancer pro- branes (epithelia) exhibit the highest degree of comparabil- gression. The remainder of this section outlines a number of ity. Metastases also occur, but more rarely, in invertebrates; selected chain reactions leading to neoplastic development and are discussed as they are found in the nonmammalian in certain members of these chains. A discussion of the vertebrates: in fish, amphibians, reptiles, and birds. Diseases storage of chemical carcinogens in plants and their interac- ofthe leukemia (Ieucosis)-Iymphoma complex are present in tion with other causes of neoplastic growth is also included.