Expression of microRNA-145, OCT4, and SOX2 in double primary endometrioid endometrial and ovarian carcinomas

Double primary endometrioid endometrial and ovarian carcinomas (DPEEOCs) are the most common multiple gynecological carcinomas. In recent years, gene sequential comparison analysis has strongly supported the opinion that sporadic double endometrioid endometrial and ovarian cancers (DEEOCs) are clonally related in both primary and metastatic tumors. In order to find more clonal evidence for DPEEOC, we investigated cancer stem cells (CSCs). SOX2 and OCT4 are two common factors in CSCs. MicroRNA (miRNA)-145, a small non-coding RNA, has effects in regulating gene expression and tumorigenesis in CSCs. The aim of this study was to assess the involvements of SOX2, OCT4, and miRNA-145 in the tumorigenesis of DPEEOCs. In our study, twenty DPEEOC patients were chosen. Metastatic DEEOCs and normal endometrial and ovarian tissues were also included. The expression of miRNA-145 was detected by real-time quantitative PCR. Immunohistochemical staining was used to measure the expression of OCT4 and SOX2. The results showed that miRNA-145 expression was lower in DPEEOC endometrial tissues and higher in DPEEOC ovarian tissues compared to the corresponding normal tissues. Both SOX2 and OCT4 were over-expressed in cancer tissues compared with that in normal tissues. MiRNA-145, SOX2, and OCT4 were expressed at similar levels in two cancer sites of a given DPEEOC or metastatic DEEOC sample. Besides, metastatic DEEOC sections expressed a higher level of SOX2 and OCT4 compared to the corresponding DPEEOC tissues. Together, these results support the clonality of DPEEOCs. Moreover, SOX2 and OCT4 may have some implication in DPEEOC and metastatic DEEOC diagnosis.