This study detected the content of SP cells in endometrial cancer cell lines with different expression statuses of estrogen and progesterone receptor, and the results showed that there were different numbers of SP cells among the HEC-1A (0.3–3.0%), Ishikawa (0.2–6.5%), and RL95-2 (1.8–4.3%) cell lines and that there were no differences in the proportions of SP cells among the three kinds of cell lines, which was consistent with the results in the literature. This evidence concerns the gene PGR and endometrial cancer.