Noriyuki Takai

Human ovarian carcinoma cells: histone deacetylase inhibitors exhibit antiproliferative activity and potently induce apoptosis.

Histone deacetylase inhibitors (HDACIs) can inhibit proliferation, stimulate apoptosis, and induce cell cycle arrest in malignant cells.

Expression of polo-like kinase in ovarian cancer is associated with histological grade and clinical stage

Polo-like kinase (PLK), a cell cycle-regulated, cyclin-independent serine/threonine protein kinase, has been shown in recent reports to play a critical role during tumorigenesis. To investigate whether PLK plays a general role as a tumor marker of ovarian cancers, we examined the expression of PLK protein in ovarian cancers, and analyzed the relationship between PLK protein expression and histological grade. Immunohistochemically, the majority of PLK was found in the cytoplasm (around the nucleus), and a portion was found in the nucleus of ovarian cancer glands and also in the fluid secreted from these glands. PLK was expressed at the basement membrane of cancer glands and partly expressed in the head portion of papillary cancer tissues. A significant correlation was found between percentages of PLK-positive cells and histological grade of ovarian cancer (P<0.001). However, the expression of proliferating cell nuclear antigen, Ki-67, and cyclin B1 was independent of PLK expression. Taken together, these findings suggest that PLK expression may reflect the degree of malignancy rather than the degree of proliferation in ovarian cancer. Thus, in addition to being of diagnostic value, PLK activity in ovarian tumors may be modulated by chemotherapeutic agents or gene therapy to therapeutic effect.

Id1 expression is associated with histological grade and invasive behavior in endometrial carcinoma.

Basic helix-loop-helix (bHLH) DNA-binding proteins have been reported to regulate tissue-specific transcription of cellular differentiation within multiple cell lineages. The Id family of helix-loop-helix proteins does not possess a basic DNA-binding domain and functions as a negative regulator of bHLH proteins by forming high-affinity heterodimers with bHLH proteins. Id proteins were originally characterized as inhibitors of DNA binding and cell differentiation. Thus, overexpression of Id proteins correlates with cell proliferation and arrested differentiation in many cell lineages. To elucidate the involvement of Id1 in endometrial carcinogenesis, we analyzed serial frozen sections for Id1 protein expression in 20 cases of endometrial carcinoma and 20 cases of normal endometria by fluorescent immunohistochemistry. We analyzed the relationship between the percentages of Id1-stained cells and the patients characteristics, including histological grade, clinical stage, presence of invasion to >1/2 myometrium, and clinical outcome. In normal endometria, Id1 was not detected in either the proliferative or the secretory phase. There was, however, abundant Id1 immunoreactivity in the endometrial carcinoma cells. Moreover, Id1 was strongly expressed in the inflammatory cells. Scoring on the basis of the percentage of positive cells indicated that Id1 expression is significantly associated with histological grade (P<0.05) and the presence of invasion to >1/2 myometrium (P<0.05). Our results demonstrate that increased Id1 expression in endometrial carcinoma correlates with the malignant potential of this tumor.

Polo-like kinase (PLK) expression in endometrial carcinoma

Polo-like kinase (PLK) is a cell cycle-regulated, cyclin-independent serine/threonine protein kinase. Recent reports have shown a critical role for PLK during tumorigenesis. To explore whether PLK plays a general role as a tumor marker of endometrial carcinomas, we examined the expression of PLK mRNA and protein in endometrial carcinomas and normal endometrium, and analyzed the relationship between PLK protein expression and malignant potential. We found that PLK mRNA was expressed in all specimens from endometrial carcinoma patients using RT-PCR methods, although some specimens from normal endometria were negative. Immunohistochemically, most of the PLK was found in the cytoplasm (around the nucleus), and partly in the nucleus of endometrial carcinoma glands and also secreted tissues from endometrial carcinoma glands. PLK was expressed at the basement membrane of carcinoma glands and partly expressed in the head portion of papillary carcinoma tissues. There was a significant correlation between percentages of PLK-positive cells and histological grade of endometrial carcinoma (P<0.0001). However, the expression of proliferating cell nuclear antigen and Ki-67 was independent of PLK expression. Moreover, we noted that PLK is strongly expressed in invading carcinoma cells. PLK expression could reflect the degree of malignancy and proliferation in endometrial carcinoma. Thus, in addition to being of diagnostic value, modulation of PLK activity in the tumors by chemotherapeutic agents or gene therapy may prove to be of therapeutic value.

Expression of c-Ets1 is associated with malignant potential in endometrial carcinoma

The protooncogene c‐ets1 is a transcriptional factor that controls the expression of a number of genes involved in extracellular matrix remodeling. It might play a role in the regulation of physiologic processes such as cell proliferation and differentiation and also is associated with angiogenesis, cell migration, and tumor invasion.

Endometrioid Adenocarcinoma Arising from Adenomyosis

In spite of many references to carcinoma arising from endometriosis at extrauterine sites, there are few documented cases of carcinoma developing in association with adenomyosis. We present 2 rare cases of adenocarcinoma arising from adenomyosis. The relationship between prior frequent estrogen use and carcinogenesis and the possible effects of chemotherapy and radiation therapy are reviewed.

Intraplacental choriocarcinoma with fetomaternal transfusion

Intraplacental choriocarcinoma is very rare, and is usually found only after maternal and fetal metastatic disease is identified. The purpose of this case report is to review the incidence and findings of intraplacental choriocarcinoma. A term placenta was investigated because the newborn was born with severe anemia (Hb 3.0 g/dL). A 2 cm nodule was noted on the surface of the amniotic membrane and grossly resembled an infarction. The tumor was examined microscopically with immunohistochemical staining for the alpha‐ and beta‐human chorionic gonadotropin (α‐hCG, β‐hCG) subunits, human placental lactogen (hPL) and Ki‐67. Microscopically, the tumor consisted of necrotic areas with proliferation of atypical trophoblastic cells and destruction of the villi and capillaries. The cells were positive for the α‐hCG, β‐hCG subunits, hPL and Ki‐67, consistent with intraplacental choriocarcinoma. The mother and newborn were investigated for the presence of metastatic disease. Computed tomography scans and magnetic resonance imaging of the mother and infant were negative for metastatic disease. Choriocarcinoma, limited only to the placenta with no evidence of metastatic disease is very rare. Primary intraplacental choriocarcinoma may frequently be overlooked or missed, and choriocarcinoma may possibly arise in the placenta more often than in retained or persistent trophoblast following pregnancy.

Expression of polo-like kinase (PLK) in the mouse placenta and ovary.

The polo-like kinase (PLK) is a mammalian serine/threonine kinase involved in cell cycle regulation. Much evidence for the role of PLK in the cell cycle has come from studies of cultured cells; however, little is known about its function or even expression in vivo. The present study examined the features of PLK expression in the mouse placenta and ovary. Immunohistochemical studies showed that PLK is highly expressed in the basement membrane of the endometrial gland, in some endothelial cells, in endometrium after embryo implantation, in trophoblastic tissue invading the decidua, in the ovarian stroma and in some lutein bodies. In contrast, PLK was not detectable by immunohistochemistry in endometrial stroma before decidualization, in decidua, in trophoblastic tissue not invading the decidua or in ovarian follicles. PLK expression seemed to be correlated with the expression of proliferation cellular nuclear antigen (PCNA) in many placental and ovarian cells, reflecting a role in cellular proliferation. Nevertheless, in ovarian stroma and lutein bodies where PCNA was not expressed, PLK was strongly expressed. This finding indicates that PLK may have some post mitotic functions in certain specialized cell types.

Homologous carcinosarcoma of the uterine corpus associated with tamoxifen therapy

Abstract A very rare case of homologous carcinosarcoma of the endometrium associated with long-term tamoxifen treatment for breast cancer is reported. A 70-year-old Japanese woman was admitted with atypical genital bleeding. Six years earlier, she had undergone total right mastectomy for breast cancer, and administration of tamoxifen had been started postoperatively. On admission, biopsy revealed a homologous carcinosarcoma of the endometrium with metastasis in the endocervix. The patient underwent a Wertheims hysterectomy that revealed stage IIIc disease with pelvic lymph node metastasis. She received six courses of adjuvant chemotherapy. Histological examination showed a homologous carcinosarcoma, composed of poorly differentiated adenocarcinoma and anaplastic sarcoma. No heterologous elements; for example, malignant cartilage or rhabdomyoblasts, were seen. Tamoxifen is a possible etiologic factor in the development of endometrial carcinosarcomas.