Molecular Events in Tumor Development

Abstract

IT is now widely accepted that most tumors are clonal, arising from a single altered cell. There is also evidence that tumor progression, the tendency of a neoplasm to become more aggressive in its clinical and biologic characteristics over time, frequently results from a series of acquired genetic changes within the neoplastic clone, giving rise to subpopulations of tumor cells with increasingly aggressive characteristics. This evolution may occur, in part, because the genetic apparatus of tumor cells is abnormally unstable. An example was recently described in these pages¹: the progression of a relatively indolent follicular lymphoma, in which all . . .