Introduction

This volume reports on the proceedings of the Workshop on Control of Cell Proliferation in Senescent Cells, which was held at the National Institute on Aging in Bethesda, MD on December 12, 1985. Among mammals, however, the phenotype of senescent organisms is characterized by a striking loss of proliferative homeostasis, including multifocal hyperplasias. Thus, the concern of a number of the contributors for the problem of the interface between clonal senescence and oncogenesis is quite important. In yeast, there are at least 70 different cell cycle division genes, and many more are likely to be discovered that influence cell cycle function. In mammals, even at the single cell level, many growth factors can have both stimulatory and inhibitory effects or can stimulate cell cycle traverse in one cell type but inhibit it in another.8 Moreover, it will be essential to consider cell-cell interactions, as emphasized by Audrey Muggleton-Harris.