Tumors can be induced by a variety of physical and chemical carcinogens. The resulting tumor cells are usually abnormal in their morphology and behavior and transmit their abnormalities to their daughter tumor cells. Most theories of the pathogenesis of tumors suggest that carcinogens in some way cause alterations either of the genomes or of inheritable patterns of gene expression in normal cells, which then cause morphological and behavioral changes. This volume presents a collection of articles aimed at the question by what genetic or epigenetic mechanisms carcinogens can cause morphological abnormalities of tumor cells. It includes reviews of cellular targets of known carcinogens, and presents varying viewpoints of how morphological abnormalities and the actions of carcinogens might be related. The volume will be of interest to all those who are involved in cancer research or in the prevention, diagnosis or management of tumors in humans or animals.

Zusammenfassung
This volume began with an invitation from the publishers to edit a volume of EXS on Cancer. This invitation undoubtedly derived from my articles in Cellular and Molecular Life Sciences in 2002 and 2003 on the relationships between the morphology, aetiology and pathogenesis of tumours, especially in relation to genetic instability. After many years of teaching the theories of c- cer in undergraduate medical school courses, it seemed to me that the variably chaotic histopathologic features of tumours parallel in some way, the variably unstable genomes of tumour cells, which were being discovered in the 1990s. Thus the title of the volume has come to include morphology, carcinogenesis and genetic instability. The invitation came while I was working with Herrn Dr. med. Hubertus Jersmann (MD Düsseldorf, PhD, now Senior Lecturer in Medicine of the University of Adelaide) and Professor Brian Coghlan (Emeritus Professor of German, the University of Adelaide), on the work of the nineteenth century cancer pathologists, especially David Paul von Hansemann (18581920). With the delivery of the manuscripts from the authors of the chapters, it became obvious that a background chapter for the volume could include some of the material which we had uncovered together. Because of this, chapter 1 is authored by the three of us, and the new material figures prominently.

Inhalt
Cancer morphology, carcinogenesis and genetic instability: a background.- Abnormalities of chromatin in tumor cells.- Aneuploidy, stem cells and cancer.- The mode of action of organic carcinogens on cellular structures.- Metal ions and carcinogenesis.- Actions of ultraviolet light on cellular structures.- Actions of radiation on living cells in the post-bystander era.- Viral carcinogenesis and genomic instability.- Abnormalities of cell structures in tumors: apoptosis in tumors.- Molecular regulation of tumor angiogenesis: mechanisms and therapeutic implications.- Genetic and environmental factors in hereditary predisposition to tumors: a conceptual overview.- Effects of ionizing radiation on cellular structures, induced instability and carcinogenesis.- Genetic instability in human tumors.- Molecular mechanisms of human carcinogenesis.- Mechanisms of abnormal gene expression in tumor cells.