Comparative biology of mouse and human embryonal carcinoma

The biology of human germ cell neoplasia has been the subject of increasing investigation during the past decade. The objectives of such investigations include better understanding of the pathogenesis of the diseases, improvement in patient management, and insights into cancer cell differentiation and human development. Many of the approaches to human germ cell tumour biology have been strongly influenced by work in the mouse. Here we review some comparative aspects of germ cell tumours in mouse and man. There are striking differences between the two species in the mechanisms of tumour development, the role of genetic background in tumour susceptibility, the cytogenetics of the tumours, and the phenotype of the embryonal carcinoma stem cells. Despite these differences, certain common themes emerge from a survey of work on growth factors and their receptors, extracellular matrix molecules and transcriptional regulators. Both mouse and human embryonal carcinoma cells produce growth factors, but strong evidence for autocrine regulation of stem cell growth is lacking in both species. Differentiated derivatives (primarily extraembryonic endoderm) of mouse embryonal carcinoma cells may respond to factors produced by the stem cells. These differentiated cells also secrete high levels of growth factors and extracellular matrix molecules in both species, supporting a role for paracrine growth interactions in peri-implantation development. The requirements of embryonal carcinoma stem cells for cell substrate adhesion molecules are specific and differ in mouse and man. There are some similarities in the induction of putative transcriptional regulators by retinoids in human and mouse embryonal carcinoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)