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Table 2 Functional characterization of isolated epithelial cell subpopulations

From: Parity induces differentiation and reduces Wnt/Notch signaling ratio and proliferation potential of basal stem/progenitor cells isolated from mouse mammary epithelium

A Fraction of large colonies Fraction of double-positive colonies
  Virgins Parous Virgins Parous
Myoepitheliala 32.7 ± 7.4%a 9.6 ± 2.3%a 0% 0%
Basal stem/progenitora 66.2 ± 7.2%a 9.3 ± 4.5%a 26.1 ± 2.7% 0%
Luminal Sca1-b 36.3 ± 5.6%b 31.3 ± 2.6%b 84.0 ± 3.4% 57.1 ± 2.9%
Luminal Sca1+a 73.3 ± 1.8%a 71.8 ± 4.1%a 64.1 ± 3.6% 59.8 ± 2.7%
B
Number of basal stem/progenitor cells injected per cleared fat pad
Number of positive outgrowths c, d, e
  Age-matched virgin control donors Parous donors
1,000 c8/9 d8/9 e8/9 c3/9 d3/9 e4/9
500 c8/11 d8/11 e8/11 c2/11 d2/11 e6/11
250 c2/6 d2/6 e2/6 c0/6 d1/6 e1/6
100 c0/6 d1/6 e1/6 c0/6 d0/6 e2/6
50 c0/7 d0/7 e0/7 c1/7 d1/7 e1/7
Repopulating frequency (95% confidence interval) c1/507 (1/827 - 1/311) c1/2468 (1/5,522 to 1/1104)
  d1/472 (1/767 - 1/291) d1/2095 (1/4,441 to 1/988)
  e1/472 (1/767 - 1/291) e1/907 (1/1582 - 1/520)
P value cP = 0.0004; dP = 0.0004; eP = 0.076.
  1. A: Size and phenotype (Krt18/Krt14 double positivity) of colonies. At least 50 randomly selected colonies were examined for each group, except for colonies derived from basal stem/progenitor cells of parous mice, where all available colonies were used. Data represent the mean ± SEM of three independent experiments with a minimum of 10 mice (five virgins; five parous) per experiment. aColony size ≥ 20 cells; bColony size ≥ 100 cells. B: Limiting dilution analysis of the repopulating capacity. The basal stem/progenitor cell subpopulations from parous (n = 23) and age-matched virgin control (n = 21) mice were injected into the cleared fat pads of 3-week-old syngeneic female recipient mice in limiting dilution numbers. Epithelial outgrowths were scored 8 to 9 weeks after injection. Number of positive outgrowths of specified sizes is indicated per number of mammary fat pads injected (that is, X outgrowths per Y injections = X/Y). When analyzed statistically, as previously described [18], a significant decrease in the number of large outgrowths was observed for parous donors. cPositive outgrowth defined as ≥ 25% of fat pad filled; dpositive outgrowth defined as ≥ 10% of fat pad filled; epositive outgrowth defined as ≥ 3% of fat pad filled.