Stem Cells, Vol 11, 199-203, Copyright © 1993 by AlphaMed Press
Cancer cell societies and tumor progression
GH Heppner
Breast Cancer Program, Michigan Cancer Foundation, Detroit 48201.
It is now well accepted that cancers are heterogeneous and contain multiple
subpopulations of cancer cells that differ in important behavioral
properties, such as growth rate, ability to metastasize and sensitivity to
treatment. This review describes results using a mouse mammary tumor system
to model the effect of heterogeneity on tumor growth and response to
chemotherapy. Tumor subpopulations that differ in growth and therapy
parameters are mixed together to simulate tumor heterogeneity. The mixtures
are studied in a variety of protocols designed to detect interactions
between the subpopulations and to determine the mechanisms of these
interactions. The central conclusion of this work is that tumor
subpopulations do not behave independently of each other but rather form a
society of cells in which they influence each other's growth and treatment
response. The mechanisms by which they do so depend on the unique
characteristics of the interacting subpopulations, on the behavior being
affected and on the circumstances of their interaction. These observations
suggest that the maintenance of tumor heterogeneity is a consequence of the
cancer cell society and that cancer behavior and progression depend on
interactions among all the members of that society, not just on its most
deviant variants.
