Propensity of the tight mid-flexion and loose flexion gap despite the adjustment of extension and flexion gaps in Oxford unicompartmental knee arthroplasty: retrospective study.

PURPOSE: A well-balanced joint gap is necessary in Oxford unicompartmental knee arthroplasty (OUKA) to prevent mobile-bearing dislocation. While the gaps between 20° (extension) and 100° (flexion) are precisely adjusted using the incremental mill system, there has been insufficient evaluation of gaps in other angles. We hypothesized that the gap is not always the same in other angles. This retrospective study aimed to evaluate the gap in full-extension (0°), mid-flexion (60°) and deep flexion (130°) for comparison with those in extension and flexion gaps. METHODS: We evaluated 119 knees in 83 patients (51 females, 31 males, aged 71.9 years). The full-extension and mid-flexion gaps were compared with the extension gap, and the deep flexion gap was contrasted with the flexion gap. Each gap was classified into isometric, tight or loose, for evaluation of contributing factors. RESULTS: Although the full-extension gap tended to be isometric (45%), the mid-flexion tended to be tight (48%), whereas the deep-flexion was loose in most knees (84%) (P = 0.002). The tight mid-flexion and loose deep flexion gap pattern accounted for 44% of the total knees, especially so with smaller femoral components (P = 0.004). CONCLUSION: Our results highlight the propensity of tight mid-flexion and loose flexion gap despite the adjustment of extension and flexion gaps in OUKA. Although the effect of such a minor gap imbalance is still unknown, the pattern was more prevalent in patients with smaller-sized femoral components. Use of a larger femoral component may equalize the gap throughout the motion arc.

Characteristic of Endometrial Stromal Sarcoma by Algorithm of Potential Biomarkers for Uterine Mesenchymal Tumor.

The benign tumor uterine leiomyoma (UL) develops from the smooth muscle tissue that constitutes the uterus, whereas malignant tumor uterine sarcoma develops from either the smooth muscle tissue or stroma and is different from UL and endometrial cancer. Uterine sarcoma is broadly classified into three types: uterine leiomyosarcoma, endometrial stromal sarcoma (ESS), and carcinosarcoma. Although uterine leiomyosarcoma and ESS are both classified as uterine sarcoma, they significantly differ in terms of their sites of occurrence, symptoms, and treatment methods. Uterine leiomyosarcoma develops from the muscle tissue constituting the wall of the uterus and accounts for approximately 70% of all uterine sarcoma cases. In contrast, ESS develops from the stromal tissue beneath the endometrium and accounts for approximately 25% of all uterine sarcoma cases. ESS is classified as either low grade (LG) or high grade (HG). This case report aimed to highlight the importance of histopathologic examinations based on surgical specimens. Herein, we reported the case of a 45-year-old woman suspected of having submucosal leiomyoma of the uterus based on imaging results. Transvaginal ultrasonography and endometrial biopsy or partial dilation and curettage were performed. Contrast-enhanced magnetic resonance imaging (MRI) revealed a 32-mm mass projecting from the posterior wall of the uterus into the uterine cavity. T2-weighted imaging revealed a low signal within the mass; thus, submucosal UL was suspected. Histopathologic examination of surgical specimens obtained from a patient suspected of having submucosal UL after contrast-enhanced MRI indicated that the patient had ESS. Despite the remarkable advancements in medical imaging technology, the accuracy of contrast-enhanced MRI for detecting uterine mesenchymal tumors is limited. Therefore, histopathologic diagnosis based on surgical specimens should be performed when medical grounds for diagnosing a benign tumor on contrast-enhanced MRI are lacking.

Pathological Evidence for Residual SARS-CoV-2 in the Micrometastatic Niche of a Patient with Ovarian Cancer.

In previous clinical studies, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in cancer patients has a high risk of aggravation and mortality than in healthy infected individuals. Inoculation with coronavirus disease 2019 (COVID-19) vaccine reduces the risk of SARS-CoV-2 infection and COVID-19 severity. However, vaccination-induced anti-SARS-CoV-2 antibody production is said to be lower in cancer patients than in healthy individuals. In addition, the rationale for why the condition of patients with cancer worsens with COVID-19 is not well understood. Therefore, we examined the infection status of SARS-CoV-2 in the primary tumor and micrometastasis tissues of the patient with cancer and COVID-19. In this study, the expression of angiotensin-converting enzyme 2 (ACE2) was observed, and SARS-CoV-2 particles was detected in ovarian tissue cells in contact with the micrometastatic niche of the patient with high-grade serous ovarian cancer. We believe that the severity of COVID-19 in patients with cancer can be attributed to these pathological features. Therefore, the pathological findings of patients with advanced and recurrent ovarian cancer infected with SARS-CoV-2 may help decrease COVID-19 severity in patients with other cancer types.

Possibility of SARS-CoV-2 Infection in the Metastatic Microenvironment of Cancer.

According to a report from the World Health Organization (WHO), the mortality and disease severity induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are significantly higher in cancer patients than those of individuals with no known condition. Common and cancer-specific risk factors might be involved in the mortality and severity rates observed in the coronavirus disease 2019 (COVID-19). Similarly, various factors might contribute to the aggravation of COVID-19 in patients with cancer. However, the factors involved in the aggravation of COVID-19 in cancer patients have not been fully investigated so far. The formation of metastases in other organs is common in cancer patients. Therefore, the present study investigated the association between lung metastatic lesion formation and SARS-CoV-2 infectivity. In the pulmonary micrometastatic niche of patients with ovarian cancer, alveolar epithelial stem-like cells were found adjacent to ovarian cancer. Moreover, angiotensin-converting enzyme 2, a host-side receptor for SARS-CoV-2, was expressed in these alveolar epithelial stem-like cells. Furthermore, the spike glycoprotein receptor-binding domain (RBD) of SARS-CoV-2 was bound to alveolar epithelial stem-like cells. Altogether, these data suggested that patients with cancer and pulmonary micrometastases are more susceptible to SARS-CoV-2. The prevention of de novo niche formation in metastatic diseases might constitute a new strategy for the clinical treatment of COVID-19 for patients with cancer.

Reducing stray radiation with a novel detachable lead arm support in percutaneous coronary intervention.

BACKGROUND: Placing radioprotective devices near patients reduces stray radiation during percutaneous coronary intervention (PCI), a promising technique for treating coronary artery disease. Therefore, lead arm support may effectively reduce occupational radiation dose to cardiologists. PURPOSE: We aimed to estimate the reduction of stray radiation using a novel detachable lead arm support (DLAS) in PCI. MATERIALS AND METHODS: A dedicated cardiovascular angiography system was equipped with the conventional 0.5-mm lead curtain suspended from the table side rail. The DLAS was developed using an L-shaped acrylic board and detachable water-resistant covers encasing the 0.5-, 0.75-, or 1.0-mm lead. The DLAS was placed adjacent to a female anthropomorphic phantom lying on the examination tabletop at the patient entrance reference point. An ionization chamber survey meter was placed 100 cm away from the isocenter to emulate the cardiologist's position. Dose reduction using the L-shaped acrylic board, DLAS, lead curtain, and their combination each was measured at five heights (80-160 cm in 20-cm increments) when acquiring cardiac images of the patient phantom with 10 gantry angulations, typical for PCI. RESULTS: Median dose reductions of stray radiation using the L-shaped acrylic board were 9.0%, 8.8%, 12.4%, 12.3%, and 6.4% at 80-, 100-, 120-, 140-, and 160-cm heights, respectively. Dose reduction using DLAS with a 0.5-mm lead was almost identical to that using DLAS with 0.75- and 1.0-mm leads; mean dose reductions using these three DLASs increased to 16.2%, 45.1%, 66.0%, 64.2%, and 43.0%, respectively. Similarly, dose reductions using the conventional lead curtain were 95.9%, 95.5%, 83.7%, 26.0%, and 19.6%, respectively. The combination of DLAS with 0.5-mm lead and lead curtain could increase dose reductions to 96.0%, 95.8%, 93.8%, 71.1%, and 47.1%, respectively. CONCLUSIONS: DLAS reduces stray radiation at 120-, 140-, and 160-cm heights, where the conventional lead curtain provides insufficient protection.

Oncological Properties of Intravenous Leiomyomatosis: Involvement of Mesenchymal Tumor Stem-Like Cells.

Uterine leiomyoma, also known as fibroids, is the most common benign neoplasm of the female genital tract. Leiomyoma is the most common uterine tumor. The leiomyoma subtypes account for approximately 10% of leiomyomas. Intravenous leiomyomatosis, a uterine leiomyoma subtype, is an intravascular growth of benign smooth muscle cells, occasionally with pelvic or extrapelvic extension. Uterine leiomyosarcoma, a malignant tumor, tends to metastasize hematogenously, and distant metastasis to the lungs and liver is common. Therefore, the oncological properties of this intravenous leiomyomatosis resemble those of the malignant tumor uterine leiomyosarcoma. Cancer stem cells migrate to distant organs via intravascular infiltration, leading to micrometastases. We examined the oncological properties of intravenous leiomyomatosis using molecular pathological techniques on tissue excised from patients with uterine leiomyoma. CD44-positive mesenchymal tumor stem-like cells were detected in both patients with intravenous leiomyomatosis and uterine leiomyosarcoma. The oncological properties of intravenous leiomyomatosis were found to be similar to those of uterine leiomyosarcoma. However, in intravenous leiomyomatosis, cyclin E and Ki-67-positive cells were rare and no pathological findings suspecting malignancy were observed. It is expected that establishing a treatment method targeting cancer stem cells will lead to the treatment of malignant tumors with a low risk of recurrence and metastasis.

Correlation of anti-tumour drug resistance with epigenetic regulation.

During treatment, the development of drug-resistant tumours remains an important challenge in cancer treatment. Epigenetic changes have been reported as one of the mechanisms for anti-tumour drug resistance. In clinical practice, a combination of epigenetic-related drugs can be considered as a future selection of cancer therapeutic drugs.

Potential Novel Ovarian Cancer Treatment Targeting Myeloid-Derived Suppressor Cells.

Diagnosis by biopsy is difficult in the ovary since it is located deep in the abdomen. As a result, ovarian cancer is mostly found insidiously during exploratory laparotomy. Consequently, the early diagnosis of ovarian cancer is often difficult. The likelihood of peritoneal dissemination increases with the progress of ovarian cancer. With further progression, ovarian cancer metastasizes to the momentum, retroperitoneal lymph nodes, large intestine, small intestine, diaphragm, spleen, and other organs. Ovarian cancer has been considered a tumor that has a favorable response to chemotherapy, but more effective treatments are still being explored. Tumors use their own immune escape mechanism to evade host immunity. The immune checkpoint (IC) mechanism, one of the immune escape mechanisms, is established by programmed cell death-1 (PD-1)/PD-ligand-1 (PD-L1) communication. It has been shown that inhibiting PD-1/PD-L1 communication in various malignancies produces antitumor effects. However, the antitumor effect of ICI monotherapy on ovarian cancer is limited in actual clinical practice. In this review, we describe a novel cancer immunotherapeutic agent that targets myeloid-derived suppressor cells (MDSCs).

Effect of equalization filters on measurements with kerma-area product meter in a cardiovascular angiography system.

PURPOSE: This study aimed to evaluate the effect of equalization filters (EFs) on the kerma-area product ( K A P Q K M ) and incident air-kerma ( K a , i , Q K M ) using a kerma-area product (KAP) meter. In addition, potential underestimations of the K a , i , Q K M values by EFs were identified. MATERIALS AND METHODS: A portable flat-panel detector (FPD) was placed to measure the X-ray beam area (A) and EFs dimension at patient entrance reference point (PERP). Afterward, a 6-cm3 external ionization chamber was placed to measure incident air-kerma ( K a , i , Q e x t ) at PERP instead of the portable FPD. KAP reading and K a , i , Q e x t were simultaneously measured at several X-ray beam qualities with and without EFs. The X-ray beam quality correction factor by KAP meter ( k Q , Q 0 K M ) was calculated by A, K a , i , Q e x t and KAP reading to acquire the K A P Q K M and K a , i , Q K M . Upon completion of the measurements, K A P Q K M , K a , i , Q K M , and K a , i , Q e x t were plotted as functions of tube potential, spectral filter, and EFs dimension. Moreover, K a , i , Q K M / K a , i , Q e x t values were calculated to evaluate the K a , i , Q K M underestimation. RESULTS: The k Q , Q 0 K M values increased with an increase in the X-ray tube potential and spectral filter, and the maximum k Q , Q 0 K M was 1.18. K A P Q K M and K a , i , Q K M decreased as functions of EFs dimension, whereas K a , i , Q e x t was almost constant. K a , i , Q K M / K a , i , Q e x t decreased with an increase in EFs dimension but increased with an increase in tube potential and spectral filter, and the range was 0.55-1.01. CONCLUSIONS: K a , i , Q K M value was up to approximately two times lower than the K a , i , Q e x t values by EFs. When using the K a , i , Q K M value, the potential K a , i , Q K M underestimation with EFs should be considered.

Prospects and Problems of Cancer Genome Analysis for Establishing Cancer Precision Medicine.

The genome represents a design for creating the body, with each one being different. In cancer genomic medicine, many genes are simultaneously examined using mainly cancer tissues (the oncogene panel test), and gene mutations are revealed. Cancer treatments are then initiated according to each individual's constitution and medical condition based on gene mutations. A system for cancer genome medical treatment is currently being developed. In the treatment of several types of cancer, the "oncogene test with an oncogene companion diagnosis" is already being performed as a standard test using cancer tissue to detect one or more gene mutations. On June 1, 2019, the cancer gene panel test was covered by the national health insurance system in Japan, and a system to initiate cancer genome medical treatment has begun. The prospects and problems associated with cancer genome medicine are discussed herein.

Cellulomonas algicola sp. nov., an actinobacterium isolated from a freshwater alga.

An actinomycete strain, TKZ-21T, was isolated from a freshwater alga (Chetophoraceae) collected from the Takizawa River, Yamanashi, Japan, and examined using a polyphasic taxonomic approach. Cells were Gram-stain positive, aerobic, non-sporulating, motile, and coccoid or short rod-shaped. The strain grew in the presence of 0-4 % (w/v) NaCl, between pH 6-9.4, and over a temperature range of 15-40 °C, with optimum growth at 30 °C. The peptidoglycan type of strain TKZ-21T was A4ß, containing l-ornithine as diagnostic diamino acid and d-glutamic acid as the interpeptide bridge. The predominant menaquinone was MK-9(H4). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, ninhydrin-positive glycolipid, and unidentified phospholipids. The major cellular fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0, and the DNA G+C content was 75.6 mol%. On the basis of 16S rRNA gene sequence analysis, strain TKZ-21T was closely related to Cellulomonas fimi (98.5 % sequence similarity) and Cellulomonas biazotea (98.3 %). The genome orthoANI value between strain TKZ-21T and C. biazotea and C. fimi were 84.7 and 84.2 %, respectively. On the basis of fatty acid and MALDI-TOF MS profile analysis, phylogenetic analyses, genomic analysis, and phenotypic data, it is proposed that the isolate be classified as a representative of a novel species of the genus Cellulomonas, with the name Cellulomonas algicola sp. nov. The type strain is TKZ-21T (=NBRC 112905T=TBRC 8129T).

[Visualization of Four Intracranial Stents and In-stent Stenosis with Stenotic Models by 3D-TOF-MRA].

In recent years, various types of stents are deployed for the treatment of intracranial artery stenosis and aneurysms. Digital subtraction angiography has been considered to be the gold standard for the follow-up study. However, magnetic resonance angiography (MRA) is less invasive and the recent advances may contribute to the imaging of patients with intracranial stents. Then, a phantom study was carried out to evaluate the MR lumen visibility with these stents. Four stents [low-profile visualized intraluminal support (LVIS), Neuroform Atlas, Neuroform EZ, and Enterprise 2] were placed into plastic tubes with 3 mm inner diameter, and fixed in a container filled with agar. Time-of-flight MRA (TOF-MRA) was performed for these stents, and the signal intensities inside and outside the stents were measured on ImageJ software. Furthermore, 25%, 50%, and 75% stenosis models were created and passed through these stents to evaluate the diagnostic accuracy of in-stent stenosis. The signal intensity inside the LVIS stent was the highest among the four stents (P<0.001), and no significant difference was found between the signal intensities inside and outside the LVIS stent. The diagnostic accuracy with LVIS was also higher than that of Enterprise 2 (P<0.001). In conclusion, the visibility with LVIS indicates that TOF-MRA could be reliably utilized as a diagnostic tool for the detection of in-stent stenosis.

Expression of CAVEOLIN 1 in uterine mesenchymal tumors: No relationship between malignancy and CAVEOLIN 1 expression.

Although most smooth muscle neoplasms detected in the human uterus are benign, uterine leiomyosarcoma (Ut-LMS) is extremely malignant with high rates of recurrence and metastasis. CAVEOLIN 1 (CAV1) levels in the epithelial cells of some carcinomas have been reported to increase during tumor progression. We herein evaluated the relationship between CAV1 expression and the pathological features of patients diagnosed with uterine mesenchymal tumors at several clinical facilities. No clinical link was observed between CAV1 expression and the malignancy of human uterine mesenchymal tumors. CAV1 expression was decreased in the normal myometrium, whereas it was strongly expressed in uterine mesenchymal tumors. However, the expression of CAV1 was not a potential biomarker to distinguish Ut-LMS from other types of uterine mesenchymal tumors. The perivascular expression of CAV1 was clearly observed in all types of uterine mesenchymal tumors and myometria. Therefore, the results of the present study suggest that CAV1 may not act as a potential biomarker of uterine malignant mesenchymal tumors.

Data delivery method based on neighbor nodes' information in a mobile ad hoc network.

This paper proposes a data delivery method based on neighbor nodes' information to achieve reliable communication in a mobile ad hoc network (MANET). In a MANET, it is difficult to deliver data reliably due to instabilities in network topology and wireless network condition which result from node movement. To overcome such unstable communication, opportunistic routing and network coding schemes have lately attracted considerable attention. Although an existing method that employs such schemes, MAC-independent opportunistic routing and encoding (MORE), Chachulski et al. (2007), improves the efficiency of data delivery in an unstable wireless mesh network, it does not address node movement. To efficiently deliver data in a MANET, the method proposed in this paper thus first employs the same opportunistic routing and network coding used in MORE and also uses the location information and transmission probabilities of neighbor nodes to adapt to changeable network topology and wireless network condition. The simulation experiments showed that the proposed method can achieve efficient data delivery with low network load when the movement speed is relatively slow.

High Transferability of Neutralizing Antibodies against SARS-CoV-2 to Umbilical Cord Blood in Pregnant Women Vaccinated with BNT162b2 XBB.1.5: A Retrospective Cohort Study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) can lead to severe respiratory illness, rapid disease progression, and higher rates of intensive care unit admission in pregnant women. Infection during pregnancy is associated with an increased risk of preterm delivery, cesarean section, fetal dysfunction, preeclampsia, and perinatal death. Vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from pregnant women to their fetuses has also been observed. Although severe infections in neonates and infants are rare, newborns can experience serious consequences from COVID-19 due to their suboptimal humoral immune system protection. The amino acids in the structural proteins of SARS-CoV-2 are constantly mutating. Since around January 2023, COVID-19, caused by omicron-type SARS-CoV-2 variants, has been prevalent globally. These variants can evade the immune response triggered by traditional mRNA-based COVID-19 vaccines, such as BNT162b2. Therefore, vaccination with BNT162b2 XBB.1.5, which provides protection against omicron-type SARS-CoV-2 variants, is recommended. METHODS: This retrospective cohort study included 148 pregnant women who received the BNT162b2 XBB.1.5 vaccine at 30 partner medical institutions from September 2023 to January 2024. We examined the titers of anti-spike glycoprotein SARS-CoV-2 immunoglobin G (IgG) and IgA in the blood and umbilical cord blood obtained from the participants using ELISA. FINDINGS: Anti-spike glycoprotein SARS-CoV-2 IgG and IgA titers were highest in the blood and cord blood at late gestational age (28-34 weeks). No serious side effects or adverse events were observed in either the pregnant women or their newborns. INTERPRETATION: Pregnant women who received the BNT162b2 XBB.1.5 vaccine during gestational weeks 28 to 34 had the highest titers of anti-omicron SARS-CoV-2 variant antibodies in their blood. Moreover, these antibodies were transferred to their umbilical cord blood. To validate our findings, large cohort clinical studies involving numerous pregnant women are warranted. FUNDING: This study was funded by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS) and Grants-in-Aid for Medical Research from the Japan Agency for Medical Research and Development (AMED).

Half-value layer measurements using solid-state detectors and single-rotation technique with lead apertures in spiral computed tomography with and without a tin filter.

Solid-state detectors (SSDs) may be used along with a lead collimator for half-value layer (HVL) measurement using computed tomography (CT) with or without a tin filter. We aimed to compare HVL measurements obtained using three SSDs (AGMS-DM+ , X2 R/F sensor, and Black Piranha) with those obtained using the single-rotation technique with lead apertures (SRTLA). HVL measurements were performed using spiral CT at tube voltages of 70-140 kV without a tin filter and 100-140 kV (Sn 100-140 kV) with a tin filter in increments of 10 kV. For SRTLA, a 0.6-cc ionization chamber was suspended at the isocenter to measure the free-in-air kerma rate ( K ˙ air ) values. Five apertures were made on the gantry cover using lead sheets, and four aluminum plates were placed on these apertures. HVLs in SRTLA were obtained from K ˙ air decline curves. Subsequently, SSDs inserted into the lead collimator were placed on the gantry cover and used to measure HVLs. Maximum HVL differences of AGMS-DM+ , X2 R/F sensor, and Black Piranha with respect to SRTLA without/with a tin filter were - 0.09/0.6 (only two Sn 100-110 kV) mm, - 0.50/ - 0.6 mm, and - 0.17/(no data available) mm, respectively. These values were within the specification limit. SSDs inserted into the lead collimator could be used to measure HVL using spiral CT without a tin filter. HVLs could be measured with a tin filter using only the X2 R/F sensor, and further improvement of its calibration accuracy with respect to other SSDs is warranted.

Hereditary Gastric Cancer Is Linked With Hereditary Breast and Ovarian Cancer.

Background: Helicobacter pylori (H. pylori), a bacterium which chronically infects the stomach of approximately half the world's population, is a risk factor for the development of gastric cancer (GC). However, the underlying mechanism whereby H. pylori infection induces GC development remains unclear. Intermittent injection of the H. pylori cytotoxin-associated gene A antigen (CagA) protein into its host cell inhibits nuclear translocation of BRCA1/BRCA2, DNA repair proteins involved in the development of breast cancer/ovarian cancer. Interestingly, hereditary breast and ovarian cancer (HBOC) syndrome is associated with GC development. Here, we aimed to clarify the molecular link between H. pylori infection, BRCA1/2 pathogenic variants (PVs), GC and higher GC incidence in HBOC families. Methods: We retrospectively reviewed data from Japanese patients undergoing precision treatment using cancer genomic medicine. Results: We found a higher GC incidence in HBOC families having germline pathogenic variants (GPVs) of BRCA1/2 (2.95% vs. 0.78% in non-HBOC families). Next, we found that 96.1% of H. pylori-infected patients received cancer genomic medicine for advanced GC, and > 16% advanced GC patients had gBRCA2 PVs. Furthermore, expressing wild-type BRCA1/2 in Gan mice (a mouse model of human GC) inhibited GC development. Thus, gBRAC1/2 PVs and H. pylori infection synergistically increase the risk of GC development. Conclusion: Our study highlights the need to investigate the potential of therapeutic agents against BRCA1/2 PVs to avoid the development of GC in HBOC families. In addition, our results suggest that poly (ADP-ribose) polymerase (PARP) inhibitors could potentially inhibit GC development and progression with gBRCA1/2 PVs.

Molecular Histopathology for Establishing Diagnostic Method and Clinical Therapy for Ovarian Carcinoma.

Ovarian carcinoma (OC) is considered the deadliest gynecological malignancy. It is typically diagnosed in the advanced stages of the disease, with metastatic sites widely disseminated within the abdominal cavity. OC treatment is challenging due to the high rate of disease recurrence, which is further complicated by acquired chemoresistance caused by the reversion of the pathological variant. Therefore, more effective treatments are still being sought. Histologically, OC is classified into serous, mucinous, endometrioid, clear cell, and transitional cell carcinomas and malignant Brenner tumor. Recent clinicopathological and molecular biological studies demonstrated that these subtypes differ in histogenesis and anti-tumor agent sensitivity. In Japan, the incidence rates of the histological types of OC, namely, serous carcinoma, mucinous carcinoma, endometrioid carcinoma, and clear cell adenocarcinoma, are 39%, 12%, 16%, and 23%, respectively. Serous carcinoma is classified as high or low grade, with the former accounting for the overwhelming majority. In this study, the molecular pathological classification of OC has been described based on the characteristics of the two types of OC, types 1 and 2. Compared with Europe and the United States, Japan has a higher prevalence of type 1 OC and a lower prevalence of type 2 OC. The prevalence of each type of OC varies by race. It has been elucidated that the prevalence rate of each type of ovarian cancer in Asian countries is similar to that in Japan. Thus, OC is a heterogeneous disease. Furthermore, OC has been attributed to molecular biological mechanisms that vary among tissue subtypes. Therefore, it is necessary to conduct treatment based on accurate diagnoses of each tissue type and establish an optimal treatment strategy, and now is the transition period.