Takeshi Kajihara

Endometrial microRNAs and their aberrant expression patterns

MicroRNAs (miRNAs) are a class of small noncoding RNAs that regulate gene expression. They play fundamental roles in several biological processes, including cell differentiation and proliferation, embryo development, organ development, and organ metabolism. Besides regulating the physiological processes, miRNAs regulate various pathological conditions such as tumors, metastases, metabolic diseases, and osteoporosis. Although several studies have been performed on miRNAs, only few studies have described the miRNA expression and functions in human reproductive tract tissues. During menstruation, the human endometrium undergoes extensive cyclic morphological and biochemical modifications before embryo implantation. In addition to the ovarian steroid hormones (estrogen and progesterone), endometrial autocrine or paracrine factors and embryo-derived signals play a significant role in endometrial functions. miRNAs are considered key regulators of gene expression in the human endometrium and implantation process, and their aberrant expression levels are associated with the development of various disorders, including tumorigenesis. In this review, we summarize the studies that show the role of miRNAs in regulating the physiological conditions of the endometrium and the implantation process and discuss the aberrant expression of miRNAs in ectopic pregnancy, endometriosis, and endometrial cancer.

Genetic and histological analysis intraplacental choriocarcinoma: a case report

AbstractWe report on single case of intraplacental choriocarcinoma (IC) coexisting with feto-maternal hemorrhage from our hospital, a rare malignant tumor that occurs in the chorionic villous trophoblast. To investigate genetic and epigenetic changes to the carcinogenesis of IC, we employed cancer gene panel analysis and whole methylation analysis from a recent case of IC. By Short Tandem Repeats analysis, we confirmed that the tumor of present IC was derived from concurrent normal chorionic villous trophoblast cells. No mutation was found in 145 cancer-related genes. Meanwhile, amplification in MDM2 gene was observed. Furthermore, we observed deferentially methylated CpG sites between tumor and surrounding normal placenta in present IC case. These observations suggest that IC might be arisen as a result of aberrations of methylation rather than of DNA mutations. Further studies are needed to clarify association between aberrant methylation and choriocarcinogenesis.