This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Meyskens, F. L. Articles by Moon, T. E. Search for Related Content PubMed PubMed Citation Articles by Meyskens, F. L., Jr. Articles by Moon, T. E.

Similar Self-Renewal Properties for Different Sizes of Human Primary Melanoma Colonies Replated in Agar¹

Department of Internal Medicine and Cancer Center, University of Arizona, Tucson, Arizona 85724

Clonogenic assays currently define colonies as multicellular growth units above an arbitrarily designated cutoff size rather than by the biological function of different-sized growth units. To define the cutoff size between clusters and colonies in terms of the biological function of the cells within the growth units, we directly measured the self-renewal and proliferative capacity of cells from different-sized melanoma colonies. Primary colonies formed from cells of two patients were removed, pooled according to size, and replated, and the frequency and size distribution of the secondary colonies were analyzed. Cells from primary melanoma colonies that resulted from four to eight population doublings had similar extensive proliferative and self-renewal characteristics. The results demonstrated that self-renewal was not limited to cells in large colonies and suggested that the cutoff may be below 16 cells/growth unit. These data support the use of relatively small multicellular growth units to define colonies and measure highly proliferative human melanoma tumor cells. In addition, these methods may allow the determination of the cutoff size for other tumor types in terms of the biological function of cells rather than arbitrarily designating a cutoff size.

¹ This work was supported in part by grants from the American Cancer Society (PDT 184) and the NIH (CA 27502, CA 21839, CA 17094).

² To whom requests for reprints should be addressed.

Received 2/28/84. Accepted 12/ 5/84.