CD44 and neoplasm: Figure 4a shows that on day 21 almost all cells are dead. In other words, these cells do not come out of the postchemotherapy shock. Another trend in cellularity is seen in the T47D line (Figure 4a). The maximum decrease in cellularity is observed on day 14, but on day 21 the cellularity increases sharply, exceeding the initial level. Furthermore, on day 21 we can see the beginning of mammosphere formation (Figure 4b), which already suggests the dedifferentiation of individual EpCAM+CD44-CD24-/+ cells into tumour stem cells.