Expressions of CD133 and CD44 in primary and recurrent epithelial ovarian cancer tissues

Abstract

Objective To explore the differential expressions of ovarian cancer stem cells (OCSC) markers CD133 and CD44 in primary and recurrent epithelial ovarian cancer (EOC) tissues and its significances. Methods From January 1, 2003 to December 31, 2016, a total of 15 patients with recurrent EOC, 30 primary EOC patients with advanced stage who did not receive chemotherapy before surgery, and 30 primary EOC patients with advanced stage who received neoadjuvant chemotherapy (NACT) before surgery in West China Second University Hospital, Sichuan University were selected as research subjects, and they were included into the recurrent group (n=15), non-chemotherapy group (n=30), and NACT group (n=30). The positive expression rates and optical density (OD) of CD133 and CD44 in different types of EOC tissues were detected by immuohistochemistry. Paired chi-square test and Wilcoxon signed rank sum test were used to compare the positive expression rates and OD of CD133 and CD44 between EOC tissues of primary and recurrent surgery in recurrent group. Chi-square test and Wilcoxon rank sum test were used to compare the positive expression rates and OD of CD133 and CD44 between EOC tissues of non-chemotherapy group and NACT group. Correlation analysis of CD44 and CD133 expressions in EOC tissues was analyzed by Cramer′s V coefficient. This study met the requirements of the World Medical Association Declaration of Helsinki revised in 2013. There were no significant differences in the general clinical data of age, pathological type and grade between the three groups (P>0.05). Results ①In recurrent group, there were no statistical differences between EOC tissues of primary and recurrent surgery in positive expression rates of CD133, and OD of CD133 and CD44 (P>0.05). The positive expression rate of CD44 in EOC tissues of recurrent surgery was 86.7% (13/15), which was higher than that in primary surgery [73.3% (11/15)], and the difference was statistically significant (χ2=4.922, P=0.027). ②The OD of CD133 and CD44, and the positive expression rate of CD44 in EOC tissues of NACT group all were higher than those of non-chemotherapy group, and all the differences were statistically significant (Z=—2.176, P=0.030; χ2=5.455, P=0.020; Z=—4.759, P<0.001). ③There was correlation between the expressions of CD133 and CD44 in EOC tissues (Cramer′s V=0.462, P<0.001). Conclusions The OCSC markers CD133 and CD44 are co-expressed in EOC tissues and may co-exist on the surface of OCSC. The residue of OCSC after chemotherapy may be the real cause of EOC recurrence. Key words: Ovarian neoplasms, epithelial; Neoplastic stem cells; CD133; CD44; Immunohistochemistry; Densitometry; Women