Characterization of our 1998 report as indirect evidence for existence of mammary epithelial stem cells

Gilbert Smith   (2007-03-09 12:09)  MBTL,CCR,NCI, NIH, Bethesda MD

In this commentary, Max Wicha incorrectly characterizes our work published in 1998[2]in Development as providing INDIRECT evidence for

the existence of mammary epithelial stem cells. We feel this is an inappropriate portrayal of our seminal discovery as it diminishes its real

impact upon the mammary stem cell field while elevating the recent Nature publications from Shackleton et al and Stingl et al as the ONLY

demonstration for the fact that a single mammary stem cell can give rise to a complete functional mammary gland. This is misleading and gratuitous.

In addition, he ignores the demonstration both in our original paper and subsequently in Mech. Aging and Develop., Boulanger and Smith 2002, that serial transplantation of our retrovirally-tagged mammary outgrowths gave

rise to complete functional glands over several generations, all the while, retaining only the original retroviral tags, indicative of clonal expansion. Our research showed directly that a single mammary cell could give rise not only to ductal, alveolar and myoepithelial cells but also to two lineage-limited epithelial progenitors, originally described by Smith,GH in 1996, Breast Cancer Res.Treat.,(also not referenced).

The adjective indirect does not correctly portray our evidence for the existence of a mammary epithelial stem cell. Synonyms for indirect from Dictionary.com are incidental, unintentional, secondary. Neither indirect nor these adjectives accurately describe our research report,which was hypothesis driven and which intentionally sought to determine if one cell could provide the diverse progeny necessary to recreate an entire functional mammary

gland.

Competing interests

Reporting fairness otherwise none

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