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Thsi figure shows low expression of hLSR and no toxicity of newly developed anti-hLSR mAb in normal human and mouse tissues.

This Figure shows lipid droplets in LSR-positive OVCAR3 xenograft tissues by electron microscopy

This figure shows binding of newly developed anti-hLSR monoclonal antibody to cell surface LSR.

This article shows how to product anti-LSR antibody

This table shows no toxicity of anti-hLSR mAb in mice

This table shows the list of all the proteins identified by iTRAQ analysis including LSR.

These tables shows LSR immunostaining distribution of patients with ovarian serous carcinoma (Table S2) and clear cell carcinoma (Table S3)

This Figure shows anti-tumor activity of anti-hLSR mAb (#1-25) in EOC xenografts using SCID mice

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, but it still lacks effective treatment options. In this study, we utilized proteomic technology to identify lipolysis-stimulated lipoprotein receptor (LSR) as a new tumor antigen of EOC. Immunohistochemical analysis of EOC tissues in conjunction with survival analysis of EOC patients showed that high expression of LSR is associated with poor prognosis. High LSR expression also occurred in tumor metastases including to the lymph node and omentum. To evaluate the possible benefits of blocking this antigen in EOC, we raised a new monoclonal antibody (mAb) to human LSR (hLSR). In mouse xenograft models of hLSR+ EOC (cell lines or patient-derived tumors), we found that administration of anti-hLSR mAb inhibited tumor growth in a manner independent of both antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Mechanistic investigations showed that hLSR expression increased incorporation of very-low-density lipoprotein (VLDL) into EOC cells and that anti-hLSR mAb inhibited lipid uptake in vitro and in vivo. Moreover, VLDL promoted cell proliferation in hLSR-positive EOC cells in vitro, and this effect was inhibited by anti-hLSR mAb. While the anti-hLSR mAb studied cross reacted with the mouse antigen, we observed no adverse effects on normal organs and lipid metabolism in murine hosts. Our findings suggest that hLSR plays a key functional role in EOC development and that this antigen can be therapeutically targeted by specific mAb to improve EOC treatment.Significance: These findings offer preclinical evidence of the therapeutic efficacy of a novel targeted antibody therapy against deadly epithelial ovarian cancers. Cancer Res; 78(2); 516–27. ©2017 AACR.

OBJECTIVE. The aim of this study was to examine the significance of lymphovascular space invasion (LVSI) with a sarcomatous component on the tumor characteristics and clinical outcomes of women with uterine carcinosarcoma (UCS). METHODS. This was a secondary analysis of a prior multicenter retrospective study that examined women with stage I–IV UCS who underwent primary hysterectomy. Archived histopathology slides were reviewed and LVSI was scored as follows: LVSI with a carcinomatous component alone (LVSI-carcinoma; n = 375, 76.8%) or LVSI containing a sarcomatous component with or without a carcinomatous component (LVSI-sarcoma; n = 113, 23.2%). Qualitative metrics of LVSI were correlated to clinicopathological factors and survival outcome. RESULTS. Tumors in the LVSI-sarcoma group were more likely to have sarcoma dominance (82.1 vs. 26.4%) heterologous sarcomatous component (51.3 vs. 37.9%), low-grade carcinoma (42.5 vs. 22.4%), and large tumor size (81.0 vs. 70.2%) in the primary tumor site compared with tumors in the LVSI-carcinoma group (all p < 0.05). On multivariate analysis, LVSI-sarcoma was independently associated with decreased progression-free survival (5-year rates: 34.9 vs. 40.8%, adjusted hazard ratio [HR] 1.84, 95% confidence interval [CI] 1.36–2.50, p < 0.001), and cause-specific survival (5-year rates: 41.8 vs. 55.9%, adjusted HR 1.95, 95% CI 1.39–2.75, p < 0.001) compared with LVSI-carcinoma. Postoperative radiotherapy for women with LVSI-sarcoma had a higher reduction rate of recurrence/progression of disease (54% reduction, p = 0.04) compared with postoperative radiotherapy for women with LVSI-carcinoma (26% reduction, p = 0.08). CONCLUSION. In UCS, the presence of a sarcomatous component in LVSI is particularly prevalent when a tumor has sarcoma dominance. Our study suggests that LVSI containing a sarcomatous component may be a predictor of decreased survival for women with UCS.

OBJECTIVE: To identify risk factors for venous thromboembolism (VTE) and to examine the association of VTE and survival in women with uterine carcinosarcoma. METHODS: This multicenter retrospective study examined 906 women who underwent primary surgical treatment for stage I-IV uterine carcinosarcoma. Time-dependent analyses were performed for cumulative incidence of VTE after surgery on multivariate models. RESULTS: There were 72 (7.9%) women who developed VTE after surgery with 1-, 2-, and 5-year cumulative incidences being 5.1%, 7.3%, and 10.2%, respectively. On multivariate analysis, older age (hazard ratio [HR] per year 1.03, P = 0.012), non-Asian race (HR 6.28, P< 0.001), large body habitus (HR per kg/m(2) 1.04, P = 0.014), residual disease at surgery (HR 3.04, P = 0.003), tumor size ≥5 cm (HR2.73, P = 0.003), and stage IV disease (HR2.12, P = 0.025) were independently associated with increased risk of developing VTE. A risk pattern analysis identified that obese Non-Asian women with large tumors (13.7% of population) had the highest incidence of VTE (2-year cumulative rate, 26.1%) whereas Asian women with no residual disease (47.1% of population) had the lowest (2-year cumulative rate, 1.6%) (P< 0.001). Presence of carcinoma/sarcoma in metastatic sites was significantly associated with increased risk of VTE compared to carcinoma alone (2-year rates, 31.2% versus 8.4%, P = 0.049). VTE was independently associated with decreased progression-free survival on multivariate models (5-year rates, 24.9% versus 47.2%, HR 1.46,95%CI 1.05–2.04, P = 0.026). CONCLUSION: Our study suggests that VTE represents a surrogate marker of aggressive tumor behavior and diminished patient condition in uterine carcinosarcoma; obese Non-Asian women with large tumors carry a disproportionally high risk of VTE, suggesting that long-term prophylaxis may benefit this population.

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, but it still lacks effective treatment options. In this study, we utilized proteomic technology to identify lipolysis-stimulated lipoprotein receptor (LSR) as a new tumor antigen of EOC. Immunohistochemical analysis of EOC tissues in conjunction with survival analysis of EOC patients showed that high expression of LSR is associated with poor prognosis. High LSR expression also occurred in tumor metastases including to the lymph node and omentum. To evaluate the possible benefits of blocking this antigen in EOC, we raised a new monoclonal antibody (mAb) to human LSR (hLSR). In mouse xenograft models of hLSR+ EOC (cell lines or patient-derived tumors), we found that administration of anti-hLSR mAb inhibited tumor growth in a manner independent of both antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Mechanistic investigations showed that hLSR expression increased incorporation of very-low-density lipoprotein (VLDL) into EOC cells and that anti-hLSR mAb inhibited lipid uptake in vitro and in vivo. Moreover, VLDL promoted cell proliferation in hLSR-positive EOC cells in vitro, and this effect was inhibited by anti-hLSR mAb. While the anti-hLSR mAb studied cross reacted with the mouse antigen, we observed no adverse effects on normal organs and lipid metabolism in murine hosts. Our findings suggest that hLSR plays a key functional role in EOC development and that this antigen can be therapeutically targeted by specific mAb to improve EOC treatment. Significance: These findings offer preclinical evidence of the therapeutic efficacy of a novel targeted antibody therapy against deadly epithelial ovarian cancers. Cancer Res; 78(2); 516–27. ©2017 AACR.

OBJECTIVE: To examine survival after recurrence (SAR) among women with recurrent uterine carcinosarcoma who received a taxane/platinum doublet as the first-line salvage chemotherapy. METHODS: We retrospectively examined 148 women with recurrent uterine carcinosarcoma who received salvage chemotherapy within a cohort of 906 uterine carcinosarcomas. An independent association of salvage chemotherapy type and SAR was examined with multivariate analysis. RESULTS: There were 71 (48.0%) women who received a taxane/platinum regimen. On univariate analysis, women who received a taxane/platinum doublet had a higher 2-year SAR rate compared to women who received non-taxane/platinum regimens (55.5% versus 34.8%, P < 0.001). On multivariate analysis, use of taxane/platinum regimen was independently associated with improved SAR compared to the non-taxane/platinum regimens (adjusted-hazard ratio [HR] 0.56, 95% confidence interval [CI] 0.35 to 0.91, P = 0.02). When stratified by disease-free interval, women with a disease-free interval ≥6 months who received a taxane/platinum doublet had a higher 2-year SAR rate compared to those who received non-taxane/platinum regimens (61.9% versus 40.0%, HR 0.46, 95% CI 0.28 to 0.75, P = 0.002); conversely, in women with a disease-free interval

BACKGROUND: To examine recurrence patterns in women with stage I uterine carcinosarcoma (UCS) stratified by adjuvant therapy pattern. METHODS: We examined 443 cases of stage I UCS derived from a retrospective cohort of 1192 UCS cases from 26 institutions. Adjuvant therapy patterns after primary hysterectomy-based surgery were correlated to recurrence patterns. RESULTS: The most common adjuvant therapy was chemotherapy alone (41.5%) followed by chemotherapy/radiotherapy (15.8%) and radiotherapy alone (8.4%). Distant-recurrence was the most common recurrence pattern (5-year cumulative rate, 28.1%) followed by local-recurrence (13.3%). On multivariate analysis, chemotherapy but not radiotherapy remained an independent prognostic factor for decreased risk of local-recurrence (5-year cumulative rates 8.7% versus 19.8%, adjusted-hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.25–0.83, P = 0.01) and distant-recurrence (21.2% versus 38.0%, adjusted-HR 0.41, 95%CI 0.27–0.62, P < 0.001). The chemotherapy/radiotherapy group had a lower 5-year cumulative local-recurrence rate compared to the chemotherapy alone group but it did not reach statistical significance (5.1% versus 10.1%, adjusted-HR 0.46, 95%CI 0.13–1.58, P = 0.22). Radiotherapy significantly decreased local-recurrence when tumors had high-grade carcinoma, sarcoma component dominance, and deep myometrial tumor invasion (all, P < 0.05); and combining radiotherapy with chemotherapy was significantly associated with decreased local-recurrence compared to chemotherapy alone in the presence of multiple risk factors (5-year cumulative rates, 2.5% versus 21.8%, HR 0.12, 95%CI 0.02–0.90; P = 0.013) but not in none/single factor (P = 0.36). CONCLUSION: Adjuvant chemotherapy appears to be effective to control both local- and distant-recurrences in stage I UCS; adding radiotherapy to chemotherapy may be effective to control local-recurrence when the tumor exhibits multiple risk factors.

The aim of our study was to evaluate possible synergistic cytotoxic effects of the combination treatment with the BH3-mimetic ABT-263 and the PARP inhibitor BMN 673 in high-grade serous ovarian cancer (HGSOC) cells using clinically achievable concentrations of each drug. In vitro cytotoxic effects of ABT-263 and BMN 673 were assessed by XTT assay in three HGSOC cell lines: OVCAR3, OVCAR8, and OV90 cells. Combination index values and synergy/antagonism volumes were used to determine synergy. The drug effects on DNA damage accumulation, cell cycle progression, apoptosis induction, and expression levels of Bcl-2 family proteins were examined to dissect molecular mechanisms. The combination treatment synergistically decreased cell viability in a concentration- and time-dependent manner in all cell lines; combination index values were 100 after 72 h of treatment. Clinically achievable concentrations of ABT-263 2 µM and BMN 673 25 nM were used to investigate mechanisms. No increase in γ-H2AX foci formation was observed with addition of ABT-263 to BMN 673 treatment. The combination treatment increased the sub-G1 and Annexin V-positive cell populations after 48 h compared with the control and each monotherapy. It also induced greater caspase-3/7 activity and PARP cleavage. ABT-263 alone and in combination with BMN 673 induced expression levels of Bim, a pro-apoptotic protein. In conclusion, the ABT-263 and BMN 673 combination resulted in synergistic cytotoxic effects against HGSOC cells through greater induction of apoptosis. This may be a novel therapeutic strategy for HGSOC.

OBJECTIVE: To examine clinico-pathological characteristics and outcomes of uterine carcinosarcoma (UCS) in women aged ≥80 years. METHODS: This is a secondary analysis of a previous multicenter retrospective study examining 906 women with stage I–IV UCS who underwent primary hysterectomy. Patient demographics, treatment types, tumor characteristics, and survival were examined across aged ≥80 (n = 82 [9.1%]), aged 60–79, (n = 526 [58.1%]), and aged < 60 (n = 298 [32.9%]). RESULTS: Women in the aged ≥80 group were more likely to be Caucasian, undergo simple hysterectomy without lymphadenectomy, and receive no postoperative therapy (all, P < 0.05). Tumors in the aged ≥80 group were more likely to have high-grade carcinoma, heterologous sarcoma, and sarcoma dominance but less likely to have lympho-vascular space invasion (all, P < 0.05). Lymphadenectomy did not improve survival in the aged ≥80 group (P > 0.05), whereas lymphadenectomy was protective for survival in the younger groups (both, P < 0.05). Postoperative chemotherapy was associated with improved progression-free survival (PFS) in the aged ≥80 group (hazard ratio [HR] 0.44, 95% confidence interval [CI] 0.22–0.89, P = 0.021). With chemotherapy treatment, women in the aged ≥80 group had PFS similar to those in the aged 60–79 group (HR 0.97, 95%CI 0.51–1.83, P = 0.92). In contrast, without chemotherapy treatment, women in the aged ≥80 group had significantly decreased PFS compared to the aged 60–79 group (HR 1.62, 95%CI 1.09–2.40, P = 0.016). Similar associations were observed for postoperative radiotherapy. CONCLUSION: Nearly 10% of women with UCS are aged ≥80 that are characterized by aggressive tumor factors. Postoperative therapy but not extensive surgery may improve survival in this age group.

PURPOSE: To propose a categorization model of uterine carcinosarcoma (UCS) based on tumor cell types (carcinoma and sarcoma) and sarcoma dominance. METHODS: This secondary analysis of a prior multicenter retrospective study examined 889 cases of UCS with available histologic evaluation. Based on survival outcome, cases were clustered into three groups: low-grade carcinoma with nondominant homologous sarcoma [type A, n = 96 (10.8%)], (1) low-grade carcinoma with heterologous sarcoma or any sarcoma dominance and (2) high-grade carcinoma with nondominant homologous sarcoma [type B, n = 412 (46.3%)], and high-grade carcinoma with heterologous sarcoma or any sarcoma dominance [type C, n = 381 (42.9%)]. Tumor characteristics and outcome were examined based on the categorization. RESULTS: Women in type C category were more likely to be older, obese, and Caucasian, whereas those in type A category were younger, less obese, Asian, and nulligravid (all P < 0.01). Type C tumors were more likely to have metastatic implants, large tumor size, lymphovascular space invasion with sarcoma cells, and higher lymph node ratio, whereas type A tumors were more likely to be early-stage disease and small (all P < 0.05). On multivariate analysis, tumor categorization was independently associated with progression-free survival (5-year rates: 70.1% for type A, 48.3% for type B, and 35.9% for type C, adjusted P < 0.01) and cause-specific survival (5-year rates: 82.8% for type A, 63.0% for type B, and 47.1% for type C, adjusted P < 0.01). CONCLUSION: Characteristic differences in clinicopathological factors and outcomes in UCS imply that different underlying etiologies and biological behaviors may be present, supporting a new classification system.

OBJECTIVE: To examine significance of sarcoma dominance (SD) patterns In uterine carcinosarcoma (UCS). METHODS: This is a secondary analysis of multicenter retrospective study examining women with stages I-IV UCS who underwent primary surgery. SD was defined as >50% of sarcoma component in uterine tumor. SD patterns were grouped as homologous sarcoma without SD (homo/non-dominance, n = 351), heterologous sarcoma without SD (hetero/non-dominance, n = 174), homologous sarcoma with SD (homo/dominance, n = 175), and heterologous sarcoma with SD (hetero/dominance, n = 189), and correlated to tumor characteristics and survival. RESULTS: SD patterns were significantly associated with age, body habitus, carcinoma type, tumor size, depth of myometrial invasion, and nodal metastasis (all, P < 0.05). On univariate analysis, SD was associated with decreased progression-free survival (PFS) and cause-specific survival (CSS) in homologous cases (both, P < 0.05) but not in heterologous cases. On multivariate models, both homologous and heterologous SD patterns remained independent prognostic factors for decreased PFS (adjusted-hazard ratio [HR] ranges: homo/dominance 1.35–1.69, and hetero/dominance 1.47–1.64) and CSS (adjusted-HR ranges: 1.52–1.84 and 1.66–1.81, respectively) compared to homo/non-dominance (all, P < 0.05). Among stage I-III disease, when tumors had SD, adding radiotherapy to chemotherapy was significantly associated with improved PFS (adjusted-HR: homo/dominance 0.49, and hetero/dominance 0.45) and CSS (0.36 and 0.31, respectively) compared to chemotherapy alone (all, P < 0.05); contrary, this association was not observed with absence of SD (all, P > 0.05). CONCLUSION: In UCS, SD impacts survival in homologous but not in heterologous type. Regardless of sarcoma types, SD was associated with decreased survival in UCS; adding radiotherapy to chemotherapy may be an effective postoperative strategy.

Uterine carcinosarcoma (UCS) is a rare type of high-grade endometrial cancer (EC) that has been understudied with population-based statistics due to its rarity. This study examined temporal trends in the proportion of UCS among women with EC.This is a retrospective observational study examining The Surveillance, Epidemiology, and End Results program between 1973-2013. Primary EC cases were eligible for analysis, and a time-specific proportion of UCS was examined during the study period.UCS was seen in 11,000 (4.7%) women among 235,849 primary EC cases. Mean age at UCS diagnosis increased from 65.9 to 71.7 years between 1973-1989 and then decreased from 71.7 to 67.0 years between 1989-2013 (both, p0.001). Proportion of Black women significantly increased during the study period (11.9%-20.0%, p0.001), whereas the proportion of White women decreased from 86.0% to 60.5% between 1987-2013 (p0.001). There was a significant increase in the proportion of UCS among primary EC from 1.7% to 5.6% between 1973-2013 (p0.001). Among type II ECs (n=76,118), the proportion of UCS also increased significantly from 6.0% to 17.5% between 1973-2013 (p0.001). An increasing proportion of UCS was seen in both young and older women but the magnitude of interval increase was larger in the older age group between 1973-2013 (60 years, from 1.3% to 3.3%. p0.001; and ≥60 years, from 2.6% to 7.0%, p0.001).Our study demonstrated that the proportion of UCS has significantly increased among EC, accounting for more than 5% in recent years.

Background and Objectives To examine survival of women with stage IV uterine carcinosarcoma (UCS) who received neoadjuvant chemotherapy followed by hysterectomy. Methods This is a nested case-control study within a retrospective cohort of 1192 UCS cases. Women who received neoadjuvant chemotherapy followed by hysterectomy based-surgery for stage IV UCS (n = 26) were compared to those who had primary hysterectomy-based surgery without neoadjuvant chemotherapy for stage IV UCS (n = 120). Progression-free survival (PFS) and cause-specific survival (CSS) were examined. Results The most common regimen for neoadjuvant chemotherapy was carboplatin/paclitaxel (53.8%). Median number of neoadjuvant chemotherapy cycles was 4. PFS was similar between the neoadjuvant chemotherapy group and the primary surgery group (unadjusted-hazard ratio [HR] 1.19, 95% confidence interval [CI] 0.75-1.89, P = 0.45). Similarly, CSS was comparable between the two groups (unadjusted-HR 1.13, 95%CI 0.68-1.90, P = 0.64). When the types of neoadjuvant chemotherapy regimens were compared, women who received a carboplatin/paclitaxel regimen had better survival outcomes compared to those who received other regimens: PFS, unadjusted-HR 0.38, 95%CI 0.15-0.93, P = 0.027; and CSS, unadjusted-HR 0.21, 95%CI 0.07-0.61, P = 0.002. Conclusion Our study found that there is no statistically significant difference in survival between women with stage IV UCS who are tolerated neoadjuvant chemotherapy and those who undergo primary surgery.

PARP inhibitors (PARPi) have been effective in high-grade serous ovarian cancer (HGSOC), although clinical activity is limited against BRCA wild type HGSOC. The nearly universal loss of normal p53 regulation in HGSOCs causes dysfunction in the G1/S checkpoint, making tumor cells reliant on Chk1-mediated G2/M cell cycle arrest for DNA repair. Therefore, Chk1 is a reasonable target for a combination strategy with PARPi in treating BRCA wild type HGSOC. Here we investigated the combination of prexasertib mesylate monohydrate (LY2606368), a Chk1 and Chk2 inhibitor, and a PARP inhibitor, olaparib, in HGSOC cell lines (OVCAR3, OV90, PEO1 and PEO4) using clinically attainable concentrations. Our findings showed combination treatment synergistically decreased cell viability in all cell lines and induced greater DNA damage and apoptosis than the control and/or monotherapies (p

OBJECTIVE: To examine tumor characteristics and survival outcome of women with uterine carcinosarcoma who had a history of tamoxifen use. METHODS: This is a multicenter retrospective study examining stage I–IV uterine carcinosarcoma cases based on history of tamoxifen use. Patient demographics, tumor characteristics, treatment pattern, and survival outcomes were compared between tamoxifen users and non-users. RESULTS: Sixty-six cases of tamoxifen-related uterine carcinosarcoma were compared to 1009 cases with no history of tamoxifen use. Tamoxifen users were more likely to be older (mean age, 69 versus 64, P < 0.001) and had a past history of malignancy (100% versus 12.7%, P < 0.001). Tamoxifen-related uterine carcinosarcoma was significantly associated with a higher proportion of stage IA disease (48.4% versus 29.9%) and a lower risk of stage IVB disease (7.8% versus 16.0%) compared to tamoxifen-unrelated carcinosarcoma (P = 0.034). Deep myometrial tumor invasion was less common in uterine carcinosarcoma related to tamoxifen use (28.3% versus 48.8%, P = 0.002). On univariate analysis, tamoxifen use was not associated with progression-free survival (5-year rates 44.5% versus 46.8%, P = 0.48) and disease-specific survival (64.0% versus 59.1%, P =0.39).After adjusting for age, past history of malignancy, stage, residual disease status at surgery, and postoperative treatment patterns, tamoxifen use was not associated with progression-free survival (adjusted-hazard ratio 0.86, 95% confidence interval 0.50 to 1.50, P =0.60)anddisease-specific survival(adjusted-hazard ratio0.68,95% confidence interval 0.36 to 1.29, P = 0.24). CONCLUSION: Our study suggests that tamoxifen-related uterine carcinosarcoma may have favorable tumor characteristics but have comparable stage-specific survival outcomes compared to tamoxifen-unrelated uterine carcinosarcoma.

Purpose A combined chemotherapy of taxane and platinum, with or without anthracycline, has been used as a standard first-line regimen. The purpose of this study was to investigate the effectiveness of second-line chemotherapy for treatment of advanced or recurrent endometrial carcinoma previously treated with a combined chemotherapy of taxane and platinum, with or without anthracycline. Methods During the 2000–2008 study period, 723 patients were diagnosed with endometrial cancer at the Departments of Obstetrics and Gynecology of the Osaka University and the Osaka Rosai Hospitals, Osaka, Japan. The subset of these cases that eventually required treatment by second-line chemotherapy was retrospectively analyzed. Results Response rate to second-line chemotherapy was 25%. Treatment-free interval (TFI) of ≥ or

Ovarian cancer is the most lethal gynecologic malignancy; thus developing new treatment options is urgently required. Molecular targeted therapies for cancers, which are generally more tolerable than widely used cytotoxic agents, have shown highly specific inhibition of target molecules. In this study, we aimed to identify a new ovarian cancer antigen and to develop a novel monoclonal antibody (mAb). Furthermore we evaluated its preclinical efficacy and analyzed the function of its antigen in ovarian cancer.To identify a new ovarian cancer antigen, cell surface membrane proteins of normal ovarian epithelial and ovarian cancer cell lines were analyzed by iTRAQ-based proteomic technology. We identified lipolysis-stimulated lipoprotein receptor (LSR) as the new therapeutic target for ovarian cancer. By the immunohistochemical analysis, significant poor prognosis was observed in high-LSR expression patients with ovarian cancer compared to patients with low-LSR expression by survival assay (p < 0.05). Our newly developed anti-LSR mAb showed significant inhibition of tumor growth in vivo against xenograft model of LSR-positive ovarian cancer cell line and patient derived LSR-positive ovarian cancer tissue (p < 0.05). In LSR-positive ovarian cancer cells, high number and large lipid droplets were observed compared to LSR-negative cells and anti-LSR mAb decreased these droplets. Moreover addition of VLDL to LSR-positive ovarian cancer cells significantly promoted the cell proliferation (p < 0.05) and anti-LSR mAb inhibited that in vitro (p < 0.05). Supporting these data, addition of VLDL to LSR-positive ovarian cancer cells significantly promoted β-oxidation-mediated lipid catabolism (p < 0.05) and anti-LSR mAb also inhibited that (p < 0.05). In addition, this anti-LSR mAb which cross-reacted with mouse LSR did not show any cytotoxicity on normal organs and lipid metabolism in mice. In summary, high expression of LSR in ovarian cancer was the poor prognostic factor. Our newly developed anti-LSR mAb showed significant tumor growth inhibition against not only LSR-positive ovarian cancer cell line but also patient derived LSR-positive ovarian cancer tissue. In LSR-positive ovarian cancer cells, high number and large lipid droplets were observed and LSR promoted cell proliferation following β-oxidation-mediated lipid catabolism. Anti-LSR mAb inhibited these processes. Our preclinical data demonstrated that targeting LSR by mAb is a promising therapy for patients with LSR-positive ovarian cancer. Citation Format: Kosuke Hiramatsu, Satoshi Serada, Takayuki Enomoto, Takuhei Yokoyama, Yusuke Takahashi, Minoru Fujimoto, Kiyoshi Yoshino, Tadashi Kimura, Tetsuji Naka. LSR promotes ovarian cancer cell growth following the activation of β-oxidation and its antibody inhibits lipid catabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4410. doi:10.1158/1538-7445.AM2017-4410

Pedunculated subserous leiomyosarcoma is a quite rare presentation of leiomyosarcoma. As of 2013, only three cases have been reported in the literature. In this case report, we document two new cases of pedunculated subserous leiomyosarcoma from uterine fundus. These two cases illustrate the difficulty of making a correct differential diagnosis between a pedunculatedsubserous uterine leiomyosarcoma and a malignant ovarian tumor before intervention. A review of the literature confirms that this site remains unusual and making the diagnosis is difficult.

Background: Chk1/2 are major cell cycle regulators in p53-deficient tumors, such as HGSOC. Chk1 plays a critical role in DNA repair, facilitating the BRCA2-RAD51 interaction by phosphorylating the BRCA2 C-terminal domain and Thr309-RAD51. Clinical activity with the Chk1/2 inhibitor, LY2606368 mesylate monohydrate (LY), has been observed in solid tumors. We hypothesize that Chk1 inhibition would sensitize HGSOC to PARP inhibition (PARPi) by preventing nuclear RAD51 foci formation, thus impairing DNA repair. We investigated potential synergy of the combination of LY and the PARPi, olaparib (O), in HGSOC cell lines, testing lower concentrations than clinically attained. Materials and Methods: We examined cytotoxicity, DNA damage, and nuclear RAD51 foci formation by LY and/or O using XTT assay, comet assay and immunofluorescence (IF), in 3 HGSOC cell lines: two BRCA1/2 wild type (CAOV3, OV90), and one with BRCA2 mutation (PEO1). We examined a dose range based on clinically achievable concentrations of LY (0.53μM–1.34μM) and O (7.8μM–11.0μM) and calculated IC50 concentrations for cytotoxicity. The combination index (CI) was calculated to evaluate synergism. DNA damage and nuclear RAD51 foci formation were examined. DMSO was used as vehicle control. All experiments were performed in at least three replicates in all cell lines. Results are presented as mean ± SEM. Results: LY alone yielded cytotoxicity in CAOV3, OV90, and PEO1 with IC50 6.34nM, 35.2nM, 12.6nM, respectively. O 5μM monotherapy resulted in 47%, 13%, and 69% cytotoxicity in CAOV3, OV90, and PEO1. LY/O combination showed 51%, 58% and 82% cell injury in CAOV3, OV90 and PEO1. CI values indicated cytotoxicity synergism with the combination. LY/O (5nM/5μM) treatment showed greater DNA damage than O alone in OV90 and PEO1 (p Conclusions: Our preliminary results suggest synergistic activity of the combination of LY and PARPi in HGSOC cell lines using concentrations that are lower than clinically attainable in patients. Citation Format: Yeong-ran Ahn, Takuhei Yokoyama, Minshu Yu, Nicolas Gordon, Elise C. Kohn, Jung-min Lee. The cell cycle checkpoint kinase 1/2 inhibitor, LY2606368 with PARP inhibition results in synergistic cytotoxicity in high-grade serous ovarian cancer (HGSOC) at lower than physiologically administered concentrations. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 264.

Serum tumor markers have a major role in the screening, diagnosis, and monitoring of most of the gynecologic cancers. Ovarian cancer is one of the deadliest of the group because it is so frequently asymptomatic until it has advanced to an untreatable stage. Even serum cancer antigen-125 (CA-125), clinically one of the most reliable serum markers for ovarian cancer, is elevated in only half of early-stage still-treatable tumors. Because of the very low prevalence of ovarian cancer in the general population, at present, there is no cost-effective imaging or simple microscopic screening test for ovarian cancer as there is for breast and cervical cancers. However, recent proteomics and nucleic acid–based analyses have shown great promise for the discovery of new and more useful serum biomarkers, which cumulatively might provide such a screening tool. In this review, we will discuss both the currently used serum tumor markers for screening, diagnosis, monitoring of ovarian cancer, and the novel biomarkers that are now under investigation and validation. Cancer Epidemiol Biomarkers Prev; 21(11); 1902–12. ©2012 AACR.

The aim of the study was to analyze the effectiveness of salvage chemotherapy for recurring ovarian carcinoma during or after consolidation chemotherapy.During the study period, 12 patients received salvage chemotherapy for recurrence during or after consolidation chemotherapy. These cases were retrospectively reviewed.The response rate for salvage chemotherapy was 67% and was significantly associated with treatment-free interval (TFI) after consolidation (p=0.038). Progression-free survival was also significantly related to TFI (p=0.032). Combination chemotherapy of cisplatin plus irinotecan was effective in all five cases with TFI≥6 months and in three out of seven cases with TFI6 months.Our study provides, for the first time, evidence that effectiveness of salvage chemotherapy for recurrent ovarian carcinoma occurring during or after consolidation chemotherapy can be predicted by TFI, and that combination chemotherapy of cisplatin plus irinotecan is potentially useful for these cases.

The aim of this study was to determine if the disease-free interval after initial surgical resection has any useful prognostic value for recurrent endometrial carcinoma patients.Between 1998 and 2007, complete resection of endometrial carcinoma was achieved in 536 cases at the Departments of Obstetrics and Gynecology of the Osaka University and Osaka Rosai Hospitals of Osaka, Japan. Clinical characteristics of these cases were retrospectively reviewed.Recurrence was subsequently detected in 54 cases. Overall survival after recurrence in 27 patients with recurrences earlier than 12 months who received no postoperative therapy, radiation, and chemotherapy as an adjuvant therapy were significantly shorter than that of those with recurrences later than 12 months with similar treatments. Multivariate analysis demonstrated that the disease-free interval was an independent factor for prognosis.We demonstrate a significantly worse prognosis in cases with early versus late recurrence of resected endometrial carcinomas, irrespective of the type of adjuvant therapy.

Ovarian cancer is the most lethal gynecologic malignancy; thus developing new treatment options is urgently required. Molecular targeted therapies for cancers, which are generally more tolerable than widely used cytotoxic agents, have shown highly specific inhibition of target molecules. We previously identified bone marrow stromal antigen 2 (BST2) as an endometrial cancer antigen using iTRAQ-based quantitative proteomic technology focused on cell surface membrane proteins, and also demonstrated the usefulness of an anti-BST2 monoclonal antibody (mAb) for endometrial cancer. In this study, we aimed to identify a new ovarian cancer antigen. We also aimed to develop a novel monoclonal antibody (mAb) and evaluate its preclinical efficacy against ovarian cancer. To identify a new ovarian cancer antigen, cell surface membrane proteins of normal ovarian epithelial and ovarian cancer cell lines were analyzed by iTRAQ-based proteomic technology. As the new therapeutic target for ovarian cancer, we identified lipolysis-stimulated lipoprotein receptor (LSR) which had one of the largest significant differences in protein level between normal ovarian epithelial and ovarian cancer cell lines. Immunohistochemical analysis showed that the overall survival of ovarian serous carcinoma patients with high LSR expression was significantly shorter than those with low LSR (p = 0.0293). We newly developed anti-LSR mAb and investigated its preclinical efficacy. Anti-LSR mAb showed significant in vivo inhibition of tumor growth against a xenograft model of hLSR-positive ovarian cancer in an antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) independent manner (p = 0.0001). And anti-LSR mAb also induced G0/G1 cell cycle arrest by regulation of MEK and p44/42 MAPK activities and expression levels of cell cycle related proteins in vitro. Furthermore, anti-hLSR mAb, which crossreacts with mouse LSR, had little detectable toxicity in mice. In summary, high expression of LSR in ovarian cancer was the poor prognostic factor. Our newly developed anti-LSR mAb showed significant tumor growth inhibition in ADCC and CDC independent manner in vivo. Anti-human LSR mAb also inhibited LSR function and showed direct tumor growth inhibition inducing G0/G1 cell cycle arrest in vitro. Our preclinical data demonstrated that targeting LSR by mAb is a promising therapy for patients with LSR-positive ovarian cancer. Citation Format: Kosuke Hiramatsu, Satoshi Serada, Takayuki Enomoto, Satoshi Nakagawa, Akiko Morimoto, Minoru Fujimoto, Takuhei Yokoyama, Yusuke Takahashi, Yutaka Ueda, Kiyoshi Yoshino, Eiichi Morii, Tadashi Kimura, Tetsuji Naka. Anti-human LSR monoclonal antibody inhibits tumor growth of ovarian cancer directly. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4382. doi:10.1158/1538-7445.AM2015-4382

Background: The apoptosis inhibitor Bcl-xL is upregulated in recurrent ovarian cancer (OvCa). Modest clinical activity with Nav, a Bcl-2/Bcl-xL inhibitor, was observed in hematologic malignancies, although significant thrombocytopenia has been a challenge to its development. BMN 673 is a PARP inhibitor (PARPi) and is more potent at a molar level than other PARPi in preclinical studies. We observed a decrease in Bim and Bcl-2 protein expression in OvCa tissue after 1 cycle of olaparib (PARPi) and carboplatin compared to pretreatment levels; this change correlated with duration of response in BRCA1/2 mutation-related breast and OvCa patients (r2 = -0.86, p Methods: We examined cell injury, DNA damage, and apoptosis by XTT, comet assay, and caspase-3 activity in two HGSOC cell lines, CAOV3 and OVCAR8. We examined a dose range based on clinically achievable concentrations of Nav (1-8 μM) and BMN 673 (25-100 nM) and calculated IC50 concentrations for cytotoxicity. 2 μM Nav and 50 nM BMN 673 were selected to examine alone and in combination measures of DNA damage and apoptosis. Controls were cells with no treatment for comet assay, and with DMSO vehicle control for caspase-3 activity. The combination index (CI) was calculated to evaluate synergism. All experiments were performed in at least 3 replicates in all cell lines. Results are presented as mean ± SEM. Result: Nav yielded cytotoxicity in CAOV3 and OVCAR8 cells with IC50 2.67 μM and 4.39 μM, respectively. BMN 673 100 nM monotherapy yielded up to 40% cell injury in CAOV3 and 20% in OVCAR8 cells. The combination of BMN 673 50 nM and Nav 2 μM resulted in more than 80% and 30% cell injury in CAOV3 and OVCAR8, respectively. The CI indicates there is synergism in cell injury between the two drugs at or below clinically attainable concentrations. BMN 673 alone and with Nav augmented% DNA in tail in an additive fashion, over control or Nav alone in both cell lines. The effect with the combination v. Nav alone was significant in OVCAR8 (12.74% +/- 0.38 v. 9.49% +/- 0.55, p Conclusion: Our preliminary results suggest that the combination of PARP inhibition and Bcl2/Bcl-xL neutralization may be cooperative in yielding better results than either drug alone in HGSOC. Further experiments are currently underway to evaluate this novel drug combination. Citation Format: Takuhei Yokoyama, Nicolas Gordon, Minshu Yu, Elise C. Kohn, Jung-Min Lee. Navitoclax (Nav) and BMN 673 yield cytotoxicity with lower doses than used for single agents in high-grade serous ovarian cancer (HGSOC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5363. doi:10.1158/1538-7445.AM2015-5363

Background: Platinum drugs are often used for the postoperative adjuvant therapy or treatment in advanced and recurrent ovarian cancer. We have previously reported that ovarian clear cell carcinoma (CCC) has increased expression of Annexin A4 (Anx A4) in comparison with other subtype of ovarian cancer. Enhanced expression of Anx A4 has been shown to induce chemoresistance via extracellular efflux of carboplatin. Purpose: To identify the domain of Anx A4 relevant to chemoresistance. Materials and methods: Anx A4 possesses the NH2-terminal domain and four annexin repeat domains with one Ca2+-binding site in each domain. Deleting annexin repeat domains one by one from C-terminal site, we generated four deletion mutants of Anx A4 named R1, 2, 3, and 4 (arabic figure shows the number of annexin repeat domains). Stable cell lines overexpressing each deletion mutants were established in NUGC3 cells. Chemosensitivity to platinum drugs was evaluated using the MTT assay. Results. Compared with mock transfected cells, all the four deletion mutants induced chemoresistance to both cisplatin and carboplatin. Conclusions. The deletion derivative covering only one annexin repeat domain can induce chemoresistance to platinum drugs. Further study is underway to determine the specific site for chemoresistance of Anx A4. Citation Format: Akiko Morimoto, Takayuki Enomoto, Shinya Matsuzaki, Kousuke Hiramatsu, Yutaka Ueda, Kiyoshi Yoshino, Masami Fujita, Takuhei Yokoyama, Satoshi Serada, Tetsuji Naka, Tadashi Kimura. Functional domain of Annexin A4: which domain is indispensable for chemoresistance to platinum drugs. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4057. doi:10.1158/1538-7445.AM2013-4057

Because platinum drugs are often used for the chemotherapy of human cancers, when platinum resistance occurs it is a major issue. We recently reported that enhanced expression of Annexin A4 (Anx A4) increases chemoresistance to Carboplatin via increased extracellular efflux of the drug. However, the precise mechanisms of that chemoresistance, and the relationship of Anx A4 to platinum resistance in vivo, remain unclear. In this report we investigate in vitro the mechanism of platinum resistance induced by Anx A4 in endometrial carcinoma cells (HEC1 cells) which normally have a low level of expression of Anx A4. Forced expression of Anx A4 in HEC1 cells resulted in chemoresistance to platinum drugs. In addition, we compared HEC1 control cells with Anx A4-overexpressing HEC1 cells when both were xenografted to mice, Anx A4-overexpressing xenografted mice presented with significantly greater chemoresistance to Cisplatin in vivo. By immunofluorescence analysis we found that exposure to platinum drugs induced relocation of Anx A4 from the cytoplasm to the cellular membrane, where it became co-localized with ATP7A, a copper transporter also well known to be a platinum effluxer. When the expression of ATP7A was suppressed by small interfering RNA in HEC1 control cells, they showed no change of chemosensitivity to platinum drugs. However, suppressed ATP7A in Anx A4 overexpressing platinum-resistant cells, they showed improved chemosensitivity to platinum drugs, to a level comparable of that of control cells. Our results indicate that enhanced expression of Anx A4 confers platinum resistance by promoting efflux of platinum drugs via ATP7A. Citation Format: Shinya Matsuzaki, Akiko Morimoto, Satoshi Serada, Takuhei Yokoyama, Toshihiro Kimura, Eiji Kobayashi, Yutaka Ueda, Kiyoshi Yoshino, Masami Fujita, Takayuki Enomoto, Tetsuji Naka, Tadashi Kimura. Annexin A4-conferred platinum resistance is mediated by the copper transporter ATP7A. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4059. doi:10.1158/1538-7445.AM2013-4059

Endometrial cancer is one of the most common malignancies of the female genital tract. The identification of proteins for prognostic assessment and therapeutic targets in this disease is of significant clinical importance. We have previously reported a novel proteomic method for discovering potential therapeutic targets in endometrial cancer. We used a biotinylation-based approach for cell-surface protein enrichment combined with isobaric tags for relative and absolute quantitation (iTRAQ) technology using nano liquid chromatography-tandem mass spectrometry analysis to identify specifically overexpressed proteins in endometrial cancer cells compared with normal endometrial cells. We identified a total of 272 proteins, including 11 plasma membrane proteins, whose expression was increased more than twofold in at least four of seven endometrial cancer cell lines compared with a normal endometrial cell line. In addition to the identification of previously reported tumor antigens such as NCAML1, we also identified JAM-A as a novel tumor antigen in endometrial cancer by this methodology. JAM-A is a member of the immunoglobulin superfamily found at intercellular junctions of endothelial cells and epithelial cells. Some investigators have studied the role of JAM-A in carcinogenesis. However, the role of JAM-A in tumor growth and dissemination is still a debated issue. In this study, our goal is to investigate the role of JAM-A in tumor growth as well as the potential value in cancer therapeutic target. To confirm the altered expression of JAM-A in endometrial cancer, we performed flow cytometry and western blotting analysis using one immortalized normal endometrial cells (EM-E6/E7/TERT) and nine endometrial cancer cell lines (HEC-1, HEC-1A, HEC-6, HEC-88nu, HEC-108, HEC-116, SNG-II, and SNG-M). Protein expression of JAM-A was not detected in normal endometrial cells. In contrast, a considerably higher level of JAM-A expression was detected in all the nine endometrial cancer cell lines. Furthermore, to test the functional significance of JAM-A in endometrial cancer cell proliferation, the effect of JAM-A siRNA treatment was evaluated using WST-8 assay. Compared with non-target siRNA control, siRNA targeting JAM-A dramatically inhibits endometrial cancer cell proliferation. Flow cytometry with propidium iodide-staining revealed that JAM-A siRNA treatment induces cell cycle arrest in endometrial cancer cells. Taken together, our findings suggest that JAM-A may play a regulatory role in proliferation of endometrial cancer cells. Further studies are underway to identify the signal transduction pathway involved in JAM-A siRNA induced growth inhibition. Citation Format: Takuhei Yokoyama, Takayuki Enomoto, Kousuke Hiramatsu, Akiko Morimoto, Yutaka Ueda, Kiyoshi Yoshino, Masami Fujita, Tadashi Kimura, Satoshi Serada, Tetsuji Naka. Silencing of JAM-A inhibits cell growth through cell cycle arrest in endometrial cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4363. doi:10.1158/1538-7445.AM2013-4363

[Background] Endometrial cancer is one of the most common malignancy of the female genital tract in Japan, and the frequency is increasing year by year. Surgical therapy is performed as initial treatment for most of the patients. Pathological staging according to the surgical findings and the pathological findings is the most important prognostic factors. Several trials of adjuvant radiation and/or chemotherapy have been conducted for high-risk patients, but so far no standard regimen is confirmed. In this study, we established a chemo-sensitivity test for endometrial cancer using cancer-tissue originated spheroids (CTOSs). This chemo-sensitivity test can find not only the best regimen for endometrial cancer but also personalized medicine in the future. [Materials and Methods] A new primary culture system has been reported in colon cancer. These cells are called CTOS (cancer-tissue originated spheroids), in which cell-cell contact of cancer cells is retained throughout the process. By the CTOS method, highly purified and viable primary colorectal cancer cells are effectively prepared and cultured in vitro. Fresh cancerous tissues were removed from a series of 10 patients with endometrial cancer. Surgical and pathological findings revealed that 6 cases were Stage I, 1 case was Stage II, 3 cases were Stage III, 0 case was Stage IV. For histological classification, all of them were endometrioid adenocarcinoma (G1; 4 cases, G2; 4 cases, G3; 2 cases). Cancer tissues were removed and prepared as previously described by Kondo et al (PNAS, 2011). Briefly, primary culture cells are purified from the surgical specimen by mechanical and chemical treatment steps. These cells formed spheroids within 24 hours and can be cultured and expanded in stem cell culture medium. [Results] In our study, by day 14 spheroid formation was observed in 6 out of 10 cases (60%). Some of these spheroids were transplanted to subcutaneous of immune-deficient mice and formed tumors. These xenograft tumors showed quite similar appearance for their histopathology in comparison with their original tumor. For chemo-sensitivity test, spheroids were cultured in the medium with cisplatin at the day 7. The medium was changed at the day 8 exposing CTOSs to cisplatin for 1 day. The spheroids growth was inhibited in a dose-dependent manner. [Conclusion] For endometrial cancer, establishment of CTOSs allow us to analyze chemo-sensitivity as primary culture in high success rate. This approach gives a prediction of the efficacy of anti-cancer agents for personalized medicine. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4257. doi:1538-7445.AM2012-4257

BACKGROUND: Platinum drugs play the key role for postoperative adjuvant therapy and treatment in progress and recurrent ovarian cancer. We have previously reported that ovarian clear cell carcinoma (CCC) has increased expression of Annexin A4 (Anx A4) in comparison with other subtypes of ovarian cancer. Enhanced expression of Anx A4 has been shown to induce chemoresistance via extracellular efflux of carboplatin. However, it remains unclear whether targeting Anx A4 is effective for improving the sensitization against chemotherapy, like platinum drugs. The aim of this study was to evaluate the role of Anx A4 in chemoresistance in ovarian CCC. MATERIAL AND METHODS: RMG-I cell lines were used to establish the stable knockdown of Anx A4. Plasmids encoding short hairpin RNAs (shRNAs) targeting Anx A4 were transfected. Chemoresistance was assessed by IC50 value in various drugs. RESULTS: Compared with control cells, knockdown of Anx A4 gene expression in RMG-I cells induced chemosentisitzation around 2-fold to cisplatin (IC50: 11.2 μM to 5.8 μM, P Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4225. doi:1538-7445.AM2012-4225

Background. Endometrial cancer is one of the most common malignancies of the female genital tract. The identification of proteins for prognostic assessment and therapeutic targets in this disease is of significant clinical importance. Quantitative proteomic analysis provides a powerful approach in screening for alterations in protein levels and post-translational modifications that are associated with tumors. To date, proteomic studies of cancer have focused particularly on sub-cellular compartments or post-translational modifications. An analysis of the differential expression of cell-surface membrane proteins would be of particular interest, since these proteins play key roles in cell function including cell migration and drug resistance. Purpose of study. To identify membrane proteins overexpressed in endometrial cancer which may represent novel biomarkers of disease and therapeutic targets. Procedures. We developed a biotinylation-based approach for cell membrane enrichment combined with iTRAQ (isobaric tags for relative and absolute quantitation) technology using nano-LC-MS/MS analysis, to identify cell surface proteins overexpressed in seven endometrial cancer cell lines compared with a control normal endometrial cell line. Results. 365 proteins were identified, of which, 65 proteins (18%) possessed a trans-membrane domain. We identified overexpression of 24 membrane proteins in endometrial cancer cell lines compared with a normal endometrial cell line. By this proteomic approach, we identified several tumor antigens which included antigens previously associated with endometrial cancer and antigens not previously reported in this disease. Tumorigenic proteins such as neural cell adhesion molecule L1 (NCAML1), previously reported to be overexpressed in endometrial cancer, were identified. Interestingly we also identified Claudin-4, a protein associated with poor prognosis in various cancers, but not previously reported in the pathogenesis of cancer. In addition, we also successfully identified novel antigens associated with endometrial cancer. Conclusions. We developed a high throughput cell-surface membrane proteomic analysis combining biotinylation of cell-surface membrane protein and iTRAQ technology. In addition to the identification of previously reported tumor antigens such as NCAML1 and Claudin-4, we also identified novel tumor antigens in endometrial cancer by this methodology. This iTRAQ based quantitative proteomic analysis represented a useful approach in screening for novel disease biomarkers and therapeutic targets. Further studies on the physiological role of novel tumor antigens overexpressed in endometrial cancer and their application as biomarkers/therapeutic targets are underway. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5108. doi:10.1158/1538-7445.AM2011-5108