Clear cell tumors of the ovary are frequently associated with ovarian endometriosis. Clinicopathologically, it has been suggested that clear cell tumors develop from endometriosis, but there has been little molecular evidence supporting this speculation. Microarray analysis revealed recently that hepatocyte nuclear factor1beta (HNF-1beta) was significantly upregulated in clear cell carcinoma of the ovary. In the present study, we examined 30 clear cell tumors (26 malignant, three borderline, and one benign) and 40 endometriotic cysts to clarify if differentiation into the clear cell lineage already begins in ovarian endometriosis. All of the 30 clear cell tumors, including borderline and benign ones, showed immunohistochemical expression of HNF-1beta in the nucleus, while other types of ovarian epithelial tumors (endometrioid, serous, mucinous, and Brenner tumors) rarely expressed it. Among 30 clear cell tumors, 17 (56%) cases were associated with endometriosis, and endometriotic epithelium was identified in 12 cases. In nine of the 12 cases, distinct nuclear immunostaining for HNF-1beta was detected in the endometriotic epithelium, as well as in the clear cell tumor. HNF-1beta expression was observed either in atypical endometriosis (four cases), or in endometriosis of a reactive nature (five cases). Furthermore, 16 of 40 (40%) endometriotic cysts without a neoplasm also expressed HNF-1beta, and the expression was almost exclusively observed in the epithelium showing inflammatory atypia. Our results indicate that HNF-1beta is an excellent molecular marker for ovarian clear cell tumors, including benign, borderline and malignant lesions. Early differentiation into the clear cell lineage takes place in ovarian endometriosis, not only in atypical endometriosis, but also in endometriosis with degenerative and regenerative changes, and this is probably responsible for the frequent occurrence of clear cell carcinoma in ovarian endometriosis. Keywords: ovary; clear cell tumor; endometriosis; hepatocyte nuclear factor-1beta; histogenesis Among malignant epithelial tumors of the ovary, clear cell carcinomas, as well as endometrioid adenocarcinomas, are most frequently associated with ovarian endometriosis. The frequency of endometriosis is reportedly between 21 and 54% in large series of clear cell carcinomas. [1][2][3][4][5] In addition, an atypical glandular change in endometriosis, the socalled atypical endometriosis, is often present associated with clear cell carcinomas, while it is rare in endometriosis without a neoplasm. 2,6,7 Thus, many clinicopathological studies have strongly suggested a malignant transformation of endometriosis to clear cell carcinomas, but little molecular evidence exists to support the notion that endometriosis is the precursor of clear cell carcinomas. A molecular genetic study showed that ovarian endometriosis and its adjacent carcinoma shared a common allelotype; however, few clear cell carcinomas were subjected to this study. 8 Recently, a study using an oligonucleotide array technique...

Abstract:In the present paper, we introduce a transgenic mouse line whose sperm express green fluorescent protein (GFP) in their acrosome and red fluorescent protein (RFP) in their mitochondria . The dual fluorescent sperm showed normal fertilizing ability in both in vivo and in vitro fertilization and the sperm could be observed through uterine and oviductal walls when female reproductive tracts were dissected out and placed under excitation light. This characteristic could facilitate examination of sperm migration inside the female reproductive tract as well as facilitating in situ live imaging of the acrosome reaction, the details of which have remained elusive. Key words: live imaging, oviduct, sperm Fertilization is a mysterious phenomenon that is carried out between an ovulated egg and one of hundreds of millions of sperm that have been ejaculated into the female reproductive tract in human and other mammalian species. In order to elucidate the mechanism of fertilization, researchers established an in vitro fertilization (IVF) system in which oocytes collected from oviducts are mixed with sperm incubated in a "capacitating" medium [8]. Although eggs can be fertilized by sperm in the IVF system and the fertilized eggs result in healthy pups when transferred into pseudopregnant females, the IVF system is very different from real fertilization in vivo. Under natural conditions, only a part of the sperm in the uterus is considered to migrate into the oviduct.In mice and rats, the entrance forms a conical projection into the uterus called colliculus tubarius. Within the lumen of the junction, there are large and small folds in the mucosa designed to entrap sperm and prevent further ascent [6]. Histological sections and direct observation of sperm through the oviductal wall have revealed that the sperm which migrate into the oviduct are bound to the oviductal wall at the isthmus area [5]. The sperm found in the isthmus are attached by their heads to the mucosal epithelium and are believed to be awaiting ovulation there. It was postulated that sensing ovulation, a proportion of the sperm in the isthmus detaches from the oviductal wall and migrates into the ampulla part of the oviduct where fertilization occurs [5]. As reported pre--Note-

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