Conclusions
The percentage of CD44+CD24- cells varied from tumor to tumor. Our findings suggest that cancer stem cells are present in PTC.
Results
CD44+CD24- cells were present in all PTCs tested, and the percentage of these cells was higher in clinically aggressive recurrent PTC than in less aggressive primary PTCs. Higher expression of POU5F1 was found in CD44+CD24- cells compared with that of CD44+CD24+ cells. The expression of POU5F1 was higher in thyrospheroids grown in serum-free condition than in cells grown in the presence of serum from the same patient, and the tumor was initiated in mice using thyrospheroids. Conclusions: The percentage of CD44+CD24- cells varied from tumor to tumor. Our findings suggest that cancer stem cells are present in PTC.