Hideki Tokunaga

Estrogen Receptor-β, Estrogen Receptor-α, and Progesterone Resistance in Endometriosis

Loss of progesterone signaling in the endometrium may be a causal factor in the development of endometriosis, and progesterone resistance is commonly observed in women with this disease. In endometriotic stromal cells, the levels of progesterone receptor (PR), particularly the PR-B isoform, are significantly decreased, leading to a loss of paracrine signaling. PR deficiency likely underlies the development of progesterone resistance in women with endometriosis who no longer respond to progestin therapy. Here we review the complex epigenetic and transcriptional mechanisms leading to PR deficiency. The initial event may involve deficient methylation of the estrogen receptor (ER)beta promoter resulting in pathologic overexpression of ERbeta in endometriotic stromal cells. We speculate that alterations in the relative levels of ERbeta and ERalpha in endometrial tissue dictate E2-regulated PR expression, such that a decreased ERalpha-tauomicron-ERbeta ratio may result in suppression of PR. In this review, we propose a molecular model that may be responsible for changes in ERbeta and ERalpha leading to PR loss and progesterone resistance in endometriosis.

Role of Estrogen Receptor-β in Endometriosis

Endometriosis is an estrogen-dependent disease. The biologically active estrogen, estradiol, aggravates the pathological processes (e.g., inflammation and growth) and the symptoms (e.g., pain) associated with endometriosis. Abundant quantities of estradiol are available for endometriotic tissue via several mechanisms including local aromatase expression. The question remains, then, what mediates estradiol action. Because estrogen receptor (ER)β levels in endometriosis are >100 times higher than those in endometrial tissue, this review focuses on this nuclear receptor. Deficient methylation of the ERβ promoter results in pathological overexpression of ERβ in endometriotic stromal cells. High levels of ERβ suppress ERα expression. A severely high ERβ-to-ERα ratio in endometriotic stromal cells is associated with suppressed progesterone receptor and increased cyclo-oxygenase-2 levels contributing to progesterone resistance and inflammation. ERβ-selective estradiol antagonists may serve as novel therapeutics of endometriosis in the future.

Steroidogenic factor-1 and endometriosis

Endometriosis is a common and chronic disease characterized by persistent pelvic pain and infertility. Estradiol is essential for growth and inflammation in endometriotic tissue. The complete cascade of steroidogenic proteins/enzymes including aromatase is present in endometriosis leading to de novo estradiol synthesis. PGE(2) induces the expression of the genes that encode these enzymes. Upon PGE(2) treatment, coordinate recruitment of the nuclear receptor SF-1 to the promoters of these steroidogenic genes is the key event for estradiol synthesis. SF-1 is the key factor determining that an endometriotic cell will respond to PGE(2) by increased estradiol formation. The presence of SF-1 in endometriosis and its absence in endometrium is determined primarily by the methylation of its promoter. The key steroidogenic enzyme in endometriosis is aromatase encoded by a single gene because its inhibition blocks all estradiol biosynthesis. Aromatase inhibitors diminish endometriotic implants and associated pain refractory to existing treatments in affected women.

17β-Hydroxysteroid Dehydrogenase-2 Deficiency and Progesterone Resistance in Endometriosis

Estradiol (E2) stimulates the growth and inflammation in the ectopic endometriotic tissue that commonly resides on the pelvic organs. Several clinical and laboratory-based observations are indicative of resistance to progesterone action in endometriosis. The molecular basis of progesterone resistance in endometriosis may be related to an overall reduction in the levels of progesterone receptor (PR). In normal endometrium, progesterone acts via PR on stromal cells to induce secretion of paracrine factor(s) that in turn stimulate neighboring epithelial cells to express the enzyme 17beta-hydroxysteroid dehydrogenase type 2 (HSD17B2). HSD17B2 is an extremely efficient enzyme and rapidly metabolizes the biologically potent estrogen E2 to weakly estrogenic estrone. In endometriotic tissue, progesterone is incapable of inducing epithelial HSD17B2 expression due to a defect in stromal cells. The inability of endometriotic stromal cells to produce progesterone-induced paracrine factors that stimulate HSD17B2 may be due to the very low levels of PR observed in vivo in endometriotic tissue. The end result is deficient metabolism of E2 in endometriosis giving rise to high local concentrations of this mitogen. The molecular details of this physiological paracrine interaction between the stroma and epithelium in normal endometrium and its lack thereof in endometriosis are discussed.

Clinicopathological significance of circadian rhythm-related gene expression levels in patients with epithelial ovarian cancer

Objective. Recent studies implicate circadian genes in the regulation of cell cycle, apoptosis, and cell proliferation at a molecular level. These genesey affect cancer incidence, prognosis, and chemosensitivity. In this study, we measured the expression levels of clock genes and correlated their expression levels with clinicopathological parameters in epithelial ovarian cancer. Methods. The expression levels of core clock genes, per1, per2, per3, cry1, cry2, Bmal1, clock, and CKIɛ were quantified by real‐time quantitative Reverse transcription‐polymerase chain reaction in 83 ovarian cancer tissues and 11 normal ovarian tissues. Results. The expression levels of per1, per2, cry2, clock, CKIɛ in ovarian cancers were significantly lower than those in normal ovaries. In contrast, cry1 expression was highest among the eight examined clock genes, followed by per3 and Bmal1. Cry1 expression was much higher in cancer than that in normal ovaries. Localized circadian gene expression was determined in cancer cells by in situ hybridization analysis. Cry1 expression was significantly reduced in mucinous and grade 3 tumors. Bmal1 expression was also significantly reduced in mucinous adenocarcinomas as compared to other histologies. In a multivariate analysis, the combination of low cry1 expression and low Bmal1 expression was an independent prognostic factor, as well as stage and histological subtype. Conclusions. The antiphase expression of cry1 and Bmal1 may be preserved in ovarian cancers. The combination of cry1 and Bmal1 expression might become a possible prognostic marker in epithelial ovarian cancer.

Tracer injection sites and combinations for sentinel lymph node detection in patients with endometrial cancer

OBJECTIVE The aim of the present study was to clarify the most effective combination of injected tracer types and injection sites in order to detect sentinel lymph nodes (SLNs) in early endometrial cancer. PATIENTS AND METHODS The study included 100 consecutive patients with endometrial cancer treated at Tohoku University Hospital between June 2001 and December 2012. The procedure for SLN identification entailed either radioisotope (RI) injection into the endometrium during hysteroscopy (55 cases) or direct RI injection into the uterine cervix (45 cases). A combination of blue dye injected into the uterine cervix or uterine body intraoperatively in addition to preoperative RI injection occurred in 69 of 100 cases. All detected SLNs were recorded according to the individual tracer and the resultant staging from this method was compared to the final pathology of lymph node metastases including para-aortic nodes. RESULTS SLN detection rate was highest (96%) by cervical RI injection; however, no SLNs were detected in para-aortic area. Para-aortic SLNs were detected only by hysteroscopic RI injection (56%). All cases with pelvic lymph node metastases were detected by pelvic SLN biopsy. Isolated positive para-aortic lymph nodes were detected in 3 patients. Bilateral SLN detection rate was high (96%; 26 of 27 cases) by cervical RI injection combined with dye. CONCLUSION RI injection into the uterine cervix is highly sensitive in detection of SLN metastasis in early stage endometrial cancer. It is a useful and safe modality when combined with blue dye injection into the uterine body.

Ovarian epithelial carcinoma with estrogen-producing stroma

Malignant ovarian neoplasms derived from ovarian epithelium that produce estrogen are rare among postmenopausal women. Presented herein is a case of stage Ic(a) endometrioid adenocarcinoma in the right ovary of an 81‐year‐old woman, who complained of mammary tenderness, pain and atypical genital bleeding. Her serum estradiol (E2) concentration was 83 pg/mL before treatment, and the endometrial thickness measured by transvaginal ultrasonography was 5 cm, much thicker than that expected for a woman in her 80s. After surgery, her complaints disappeared and her serum E2 level decreased to normal postmenopausal levels. Immunohistochemical studies demonstrated that the enzymes required to produce estrogen were present in the tumor. Immunohistological data indicated that this epithelial ovarian cancer could produce estradiol by itself, through potential interactions between cancer cells and stromal cells, and that the high level of estradiol in the patients serum was caused by intratumoral production. This case indicates that in addition to stromal tumors, such as granulosa cell tumors, theca cell tumors, adenofibroma and so on, malignant epithelial tumors with a functioning stroma should also be considered when evaluating ovarian tumors with estrogen production in the elderly.

Identification of somatic genetic alterations in ovarian clear cell carcinoma with next generation sequencing

Ovarian clear cell carcinoma (OCCC) is the most refractory subtype of ovarian cancer and more prevalent in Japanese than Caucasians (25% and 5% of all ovarian cancer, respectively). The aim of this study is to discover the genomic alterations that may cause OCCC and effective molecular targets for chemotherapy. Paired genomic DNAs of 48 OCCC tissues and corresponding noncancerous tissues were extracted from formalin‐fixed, paraffin embedded specimens collected between 2007 and 2015 at Tohoku University Hospital. All specimens underwent exome sequencing and the somatic genetic alterations were identified. We divided the cases into three clusters based on the mutation spectra. Clinical characteristics such as age of onset and endometriosis are similar among the clusters but one cluster shows mutations related to APOBEC activation, indicating its contribution to subset of OCCC cases. There are three hypermutated cases (showing 12‐fold or higher somatic mutations than the other 45 cases) and they have germline and somatic mismatch repair gene alterations. The frequently mutated genes are ARID1A (66.7%), PIK3CA (50%), PPP2R1A (18.8%), and KRAS (16.7%). Somatic mutations important for selection of chemotherapeutic agents, such as BRAF, ERBB2, PDGFRB, PGR, and KRAS are found in 27.1% of OCCC cases, indicating clinical importance of exome analysis for OCCC. Our study suggests that the genetic instability caused by either mismatch repair defect or activation of APOBEC play critical roles in OCCC carcinogenesis.

Impact of the Great East Japan Earthquake on Regional Obstetrical Care in Miyagi Prefecture

OBJECTIVES The authors report the results of surveys on the emergency transport or evacuation status of obstetric patients conducted in Miyagi prefecture, one of the major disaster areas of the Great East Japan Earthquake and tsunami. METHODS The surveys examined the damages to maternity institutions, evacuation status and transport of pregnant women, and prehospital childbirths and were conducted in 50 maternity institutions and 12 fire departments in Miyagi. RESULTS Two coastal institutions were destroyed completely, and four institutions were destroyed partially by the tsunami, forcing them to stop medical services. In the two-month period after the disaster, 217 pregnant women received hospital transport or gave birth after evacuation. Satisfactory perinatal outcomes were maintained. Emergency obstetric transport increased to approximately 1.4 fold the number before the disaster. Twenty-three women had prehospital childbirths, indicating a marked increase to approximately three times the number of the previous year. CONCLUSION In the acute phase of the tsunami disaster, maternity institutions were damaged severely and perinatal transport was not possible; as a result, pregnant women inevitably gave birth in unplanned institutions, and the number of prehospital births was increased extremely. To obtain satisfactory obstetric outcomes, it is necessary to construct a future disaster management system and to re-recognize pregnant women as people with special needs in disaster situations. Sugawara J , Hoshiai T , Sato K , Tokunaga H , Nishigori H , Arai T , Okamura K , Yaegashi N . Impact of the Great East Japan Earthquake on regional obstetrical care in Miyagi Prefecture. Prehosp Disaster Med. 2016;31(3):255- 258.

Feasibility Study of Adjuvant Chemotherapy Using Taxane Plus Carboplatin for High-Risk Patients With Uterine Cervical Non-Squamous Cell Carcinoma After Radical Hysterectomy.

Objective We conducted this study to evaluate the efficacy and safety of adjuvant chemotherapy using taxane plus carboplatin (CBDCA) for high-risk stage IB–IIB patients with uterine cervical non-squamous cell carcinoma after radical hysterectomy. Methods Thirty-seven patients were eligible. Pelvic lymph node involvement and/or parametrial invasion were defined as high-risk factors. The patients were treated with 6 cycles of paclitaxel (PTX, 175 mg/m2) or docetaxel (DTX, 60 mg/m2) followed by CBDCA (area under the curve, 6) every 3 weeks. The primary end point was 2-year progression-free survival (PFS) rate, and the secondary end point was the assessment of adverse events. Results Twenty-two patients received PTX/CBDCA (TC) chemotherapy, and the remaining 15 patients underwent DTX/CBDCA (DC) chemotherapy. The 2-year PFS rate was 62.1% (95% confidence interval, 44.6%–75.5%). Patients receiving DC chemotherapy showed a better 2-year PFS rate compared to those with TC chemotherapy, but the difference was not statistically significant (80.0% vs 50.0%, P = 0.1400). The most common grade 3/4 adverse events were hematologic toxicities, which were generally well tolerable. Nonhematologic toxicity was generally mild. Conclusions Taxane and CBDCA combination chemotherapy, especially DC chemotherapy, may be one of the useful adjuvant treatments for high-risk stage IB–IIB patients with uterine cervical non-squamous cell carcinoma after radical hysterectomy.