Preface

     Much research has been done in the area of chemically induced tumors since Drs. Yamagiwa and Ichikawa first reported their occurrence. As a result, chemically induced carcinomas and sarcomas have been found to occur in most organs of the body. However, even if seemingly chemically induced neoplastic lesions are observed in experimental animals, one must rely on histopathological references in order to determine conclusively whether or not these are in fact neoplasms. In addition, even if a neoplasm has been clearly identified, an accurate diagnosis by a pathologist is necessary to determine whether it is benign or malignant, and if it is malignant, whether it is a carcinoma, a sarcoma or some other type of tumor. At present though, there are very few general textbooks or atlases that can serve as references on experimental oncology, and the complication which results from having to draw upon various special texts related to one's purpose and compare the content to what is needed has caused much inconvenience. This color atlas of neoplastic histology contains illustrations of chemically induced (as opposed to spontaneously occurring) tumors in rats, mice and hamsters, the animals most often used in carcinogenesis and chronic toxicity experiments. In addition, the academic level of this text is exceptionally high because it details not only neoplastic histology, but also shows initial histological changes and precancerous lesions induced by chemical compounds. Recently, the number of researchers in experimental pathology, particularly those who specialize in carcinogenesis and/or toxicity pathology, has decreased worldwide and Japan is no exception. Based on the precedent set by Drs. Yamagiwa and Ichikawa though, current Japanese research in this field is internationally recognized as being of a very high caliber. Each author of this book is actively engaged in research on experimental tumor pathology, so this text is fully expected to receive international evaluation. The authors' hope is that researchers in various fields of carcinogenesis and toxicity will utilize this atlas to deepen their knowledge of the histopathological characteristics of chemically induced tumors in experimental animals. Should it also serve to encourage further interest in experimental pathology and oncology, their goal will have been fully realized. The publication of this reference atlas would not have been possible without the extensive cooperation of several individuals at the National Institute of Health Science and Nagoya City University. We are especially grateful for the efforts of both Dr. Michihito Takahashi, chief pathologist at the National Institute of Health Science, and Dr. Hiroyuki Tsuda, assistant professor at Nagoya City University. We would also like to thank Mr. Susumu Yoshida, president, and both Mr. Muneo Okazaki and Ms. Nobuko Ishiyama of Soft Science Inc. for their considerable help in editing this book.

 

April, 1987
Nobuyuki Ito and Yuzou Hayashi