Microarray-based analysis of microRNA expression in breast cancer stem cells

Table 1 Human breast cancer xenograft assay of the ESA⁺CD44⁺CD24^-/low population

	Tumors-developed mice/cell-injected mice
Injected cell number	1 × 10⁶	5 × 10⁵	1 × 10⁵	5 × 10⁴	1 × 10⁴	5 × 10³	1 × 10³	5 × 10²
MCF-7 cell line
Unsorted MCF-7	3/3	1/3	0/3	0/3	0/3	-	-	-
ESA⁺CD44⁺CD24^-/low BCSCs	-	-	-	3/3	3/3	1/3	0/3	0/3
Xenograft tumor cells
Unsorted breast cancer cells	3/3	1/3	0/3	0/3	-	-	-	-
ESA⁺CD44⁺CD24^-/low BCSCs	-	-	-	3/3	3/3	1/3	0/3	0/3

MCF-7 cells gave rise to new tumors when at least 5 × 10⁵ cells were injected per animal but failed to do so at lower doses (10⁵ cells). By contrast, ESA⁺CD44⁺CD24^-/low cells formed tumors when 5 × 10³ cells were injected per animal. Tumor specimens were retrieved and subsequently passaged into recipient mice, and the same results were observed.

ISSN: 1756-9966