Current concepts in neuro-oncology.

Recent years have witnessed a significant resurgence of interest in neuro-oncology. This has largely been due to the use of new, potent neuro-oncogenic agents that have provided researchers with a growing body of data. New tools are being devised for the experimental study of brain tumors utilizing radiotherapeutic, chemotherapeutic, and immunological methods. In this chapter, selected observations on naturally occurring and experimentally induced nervous system tumors are discussed in relation to the following current areas of interest in oncology: (a) the somatic mutation theory of cancer and the additive mutagenic action of radiation and alkylating carcinogens; (b) the viral theory of cancer and the production of tumors by oncogenic viruses; (c) disturbances of immunological mechanisms concerned with tumor surveillance involving the central nervous system; and (d) the operation of epigenetic mechanisms in neoplastic systems, the applicability of these mechanisms to embryonal tumors of the central nervous system, and the development of suitable neural neoplastic models for the study of altered patterns of gene expression. Neural neoplasms are particularly suitable for the study of epigenetic phenomena because precise morphological, biochemical and antigenic markers exist which permit the various stages of divergent differentiation in neurocytogenesis to be clearly defined.