There is no commonly accepted mechanism to explain differentiation of either normal or neoplastic cells. Despite this fact, the organizers of the 3 rd International Conference on Differentiation recognized that there is much emerging evidence which supports the view that both normal cells and many cancer cells share common differentiative processes. Accordingly, the organizers perceived that clinical scientists and developmental biologists would greatly benefit by together considering differentiation. In that way, developmental biologists would be apprised of recent insights in cancer cell biology and the physician scientist would be updated on events in developmental biology and both would gain new understanding of the cell biology of neoplasia. A specific example may reveal the potential value of developmental biologists interacting with cancer physicians. An example chosen at random suggests that probably any paper included in the symposium volume would serve the purpose. Dr. Stephen Subtelny reviewed recent studies by his laboratory concerning germ cell migration and replication in frog embryos. How might those results interest the cancer scientist? Dr. Subtelny showed that primordial germ cells of a fertile graft will reverse their migratory direction and move into a sterile host. Perhaps in this context it would not be inappropriate to state that the germ cells of the graft metastasized into the host. Germ cells from grafts of a different species will populate the previously sterile host gonad.

Inhalt
Cell Differentiation Yesterday and Today.- Gene Injections into Amphibian Oocytes.- Organization of Transcribed and Nontranscribed Chromatin.- Visualization of Transcriptional Activity During Xenopus laevis Oogenesis.- Differential Histone Phosphorylation During Drosophila Development.- Nonhistone Proteins and Chromosome Structure.- The Current Status of Cloning and Nuclear Reprograming in Amphibian Eggs.- Control of Early Embryonic Development: An Analysis of a Cytoplasmic Component and Its Mode of Action.- Evidence of the First Genetic Activity Required in Axolotl Development.- Genetic Manipulation of the Early Mouse Embryo.- The Analysis of Cell Differentiation by Hybridization of Somatic Cells.- Chromosomal Changes Associated with Premalignancy and Cancer.- Chromosomes and Tumor Progression.- Surface Antigens in Early Embryonic Development.- The Role of Fibronectin in Cellular Behavior.- Desmin and Intermediate Filaments in Muscle Cells.- The Microtubule Cytoskeleton in Normal and Transformed Cells in Vitro.- Cytoplasmic Zone Analysis in the Study of the Polysomes of Differentiated Cells.- Mechanism of Morphogenetic Tissue Interactions: The Message of Transfilter Experiments.- In Memoriam Nelson Tracy Spratt, Jr..- Migration and Replication of the Germ Cell Line in Rana pipiens.- The Effects of Temperature-Sensitive Rous Sarcoma Virus and Phorbol Diester Tumor Promoters on Cell Lineages.- Control of Genome Integrity in Terminally Differentiating and Postmitotic Aging Cells.- On RNA Action in Differentiation: Induction and Differentiation of Somites in Chick Embryo.- RNA Viruses, Cancer and Development.- The Regulation of Differentiation in Murine Virus-Induced Erythroleukemic Cells.- Activation of Normal Differentiation Genes and the Origin and Development of Myeloid Leukemia.- Cellular Heterogeneities in Acute Myeloblastic Leukemia.- Growth Regulations of Human Malignant Cells.- The Control of Tumor Metastasis.- Hepatocarcinogenesis as a Problem in Developmental Biology.- Cell Differentiation and Its Relation to Promotion and Prevention of Bladder Cancer.- Drug-Induced Differentiation of Human Neuroblastoma: Transformation into Ganglion Cells with Mitomycin-C.- Teratocarcinogenesis and Spontaneous Parthenogenesis in Mice.- Teratocarcinoma Cells as Agents for Producing Mutant Mice.- Development of Embryo-Derived Teratomas in Vitro.- Loss of Tumorigenicity and Gain of Differentiated Function by Embryonal Carcinoma Cells.- Clinical Oncology and Cell Differentiation.