Contents

08 April 1988
Vol 240, Issue 4849

About The Cover

A multicell spheroid human squamous cell carcinoma (top) which is used as an in vitro research model for intervascular microregions of larger, solid malignant tumors or for small tumors where vascularization may be just beginning (as shown at the bottom). Spheroid diameter is approximately 300 micrometers. See page 177. [University of Rochester Cancer Center: Harvey Carapella, art director; Shari E. Harwell, layout; Chris Santarose, airbrush artist; scanning electron microscopy in collaboration with David P. Penney and Nadia Kutyreff; vascular study in collaboration with H. A. Eddy]