Uterine Serous Papillary Carcinoma Cell Research Articles

Solitomab, an EpCAM/CD3 bispecific antibody construct (BiTE), is highly active against primary uterine serous papillary carcinoma cell lines in vitro

Uterine serous carcinoma is an aggressive form of endometrial cancer that carries an extremely poor prognosis. Solitomab is a novel bispecific single-chain antibody construct that targets epithelial cell adhesion molecule on tumor cells and also contains a CD3 binding region. We evaluated the expression levels of epithelial cell adhesion molecule and the invitro activity of solitomab against primary uterine serous carcinoma cell lines invitro and ex-vivo in the ascites of patients with uterine serous carcinoma. The purpose of this study was to determine the frequency of expression of epithelial cell adhesion molecule on uterine serous carcinoma cell lines and the ability of solitomab to modulate immune responses (T-cell proliferation, activation, cytokine production, and tumor killing) to tumor cells when it is combined with lymphocytes and epithelial cell adhesion molecule-positive cell lines or epithelial cell adhesion molecule-positive ascitic fluid invitro. Epithelial cell adhesion molecule expression was evaluated by flow cytometry in a total of 14 primary uterine serous carcinoma cell lines. Sensitivity to solitomab-dependent cellular-cytotoxicity was tested against a panel of primary uterine serous carcinoma cell lines that express different levels of epithelial cell adhesion molecule in standard 4-hour chromium release assays. The proliferative activity, activation, cytokine secretion (ie, type I vs type II), and cytotoxicity of solitomab in autologous tumor-associated T cells in the ascitic fluid of patients with uterine serous carcinoma was also evaluated by carboxyfluorescein succinimidyl ester and flow-cytometry assays. Differences in epithelial cell adhesion molecule expression, solitomab-dependent cellular-cytotoxicity levels were analyzed with the use of an unpaired ttest. T-cell activation marker increase and cytokine release were analyzed by a paired t test. Surface expression of epithelial cell adhesion molecule was found in 85.7% (12 of 14) of the uterine serous carcinoma cell lines that were tested by flow cytometry. Epithelial cell adhesion molecule-positive cell lines were found resistant to natural killer cells or T-cell-mediated killing after exposure to peripheral blood lymphocytes in 4-hour chromium-release assays (mean killing ± standard of the mean, 2.7% ± 3.1% after incubation of epithelial cell adhesion molecule-positive cell lines with control bispecific antibody construct). In contrast, after incubation with solitomab, epithelial cell adhesion molecule-positive uterine serous carcinoma cells became highly sensitive to T-cell cytotoxicity (mean killing, 25.7% ± 4.5%; P < .0001) by peripheral blood lymphocytes. Exvivo incubation of autologous tumor-associated lymphocytes with epithelial cell adhesion molecule that expressed malignant cells in ascites with solitomab resulted in a significant increase in T-cell proliferation in both CD4+ and CD8+ T cells, increase in T-cell activation markers (ie, CD25 and HLA-DR), and a reduction in number of viable uterine serous carcinoma cells in ascites (P < .001). Solitomab induces robust immunologic responses invitro that result in increased T-cell activation, proliferation, production of cytokines, and direct killing of tumor cells. These findings suggest that solitomab may represent a novel, potentially effective agent for the treatment of recurrent/metastatic and/or chemo-resistant uterine serous carcinoma-overexpressing epithelial cell adhesion molecule.

Expression of αV-Integrins in Uterine Serous Papillary Carcinomas; Implications for Targeted Therapy With Intetumumab (CNTO 95), a Fully Human Antagonist Anti-αV-Integrin Antibody

Uterine serous papillary carcinoma (USPC) is an aggressive variant of endometrial cancer characterized by an innate resistance to chemotherapy and poor prognosis. In this study, we evaluated the expression of αV-integrins in primary USPC cell lines and the in vitro ability of intetumumab (CNTO 95), a fully human monoclonal antibody against αV-integrins, to inhibit USPC cell adhesion and migration. The surface expression of integrins belonging to the αV-family, including αVβ3, αVβ5, and αVβ6, was evaluated in 6 primary USPC cell lines using flow cytometry analysis. To test the ability of intetumumab to inhibit USPC cell adhesion and migration, adhesion assays in the presence of vitronectin and migration assays through an 8.0-μm pore polycarbonate membrane also were performed. We found high expression of the αV-subunit on the cell surface of all 6 primary USPC cell lines tested (100% positive cells; mean fluorescence intensity range, 13.1-39.5). When the expression of single heterodimeric integrins was evaluated, αVβ3, αVβ5, and αVβ6 were expressed on 37.5%, 32.0%, and 16.3% of cells (mean fluorescence intensity range, 6.5-16.2, 9.2-32.5, and 6.2-11.5, respectively). Importantly, in functional assays, low doses of intetumumab were effective in inhibiting adhesion (0.15 μg/mL, P = 0.003) and migration (1.25 μg/mL P = 0.02) of primary USPC cell lines. The αV-integrins are overexpressed on the cell surface of primary USPC cell lines. Intetumumab may significantly inhibit USPC cell adhesion and migration pathways and may therefore represent a novel treatment option for patients harboring this rare but highly aggressive variant of endometrial cancer.

Uterine serous papillary carcinomas overexpress human trophoblast‐cell‐surface marker (trop‐2) and are highly sensitive to immunotherapy with hRS7, a humanized anti‐trop‐2 monoclonal antibody

Uterine serous papillary carcinoma (USPC) was an aggressive and chemotherapy resistant variant of endometrial cancer. The authors evaluated the expression of human trophoblast-cell-surface-marker (Trop-2) and the potential of hRS7, a humanized anti-Trop-2 monoclonal antibody, as a novel therapeutic strategy against USPC. Trop-2 expression was evaluated by immunohistochemistry (IHC) in a total of 23 USPC. Six primary USPC cell lines were assessed by flow cytometry and real-time polymerase chain reaction (PCR) for Trop-2 expression. Sensitivity to hRS7 (Immunomedics, Inc.) antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity was tested in standard 5-hour ⁵¹Cr-release assays against primary USPC cell lines. Expression of Trop-2 was found in 15 of 23 (65%) of the tumor tissues tested by IHC and in 50% (3 of 6) of the USPC cell lines tested by real-time PCR and flow-cytometry (Trop-2 expression in USPC versus normal endometrial cells; P < .005). USPC cell lines overexpressing Trop-2, regardless of their intrinsic resistance to natural killer cytotoxicity, were highly sensitive to hRS7-mediated ADCC in vitro (range of killing, 28.2% to 64.4%) (P < .001). Negligible cytotoxicity against USPC was seen in the absence of hRS7 or in the presence of rituximab control antibody (range of killing, 1.1% to 12.4%). Incubation with interleukin-2 (50 IU/mL) in addition to hRS7 further increased the cytotoxic activity against USPC cell lines overexpressing Trop-2 (P = .008). Trop-2 was highly expressed in uterine serous carcinoma at mRNA and protein levels. Primary USPC cell lines are highly sensitivity to hRS7-mediated cytotoxicity in vitro. hRS7 may represent a novel therapeutic agent for USPC refractory to standard treatment modalities.

Differential sensitivity to platinum-based chemotherapy in primary uterine serous papillary carcinoma cell lines with high vs low HER-2/neu expression in vitro

Differential sensitivity to platinum-based chemotherapy in primary uterine serous papillary carcinoma cell lines with high vs low HER-2/neu expression in vitro

Higher sensitivity to patupilone versus paclitaxel chemotherapy in primary uterine serous papillary carcinoma cell lines with high versus low HER-2/neu expression in vitro

Objective To compare the in vitro sensitivity/resistance to patupilone versus paclitaxel in uterine serous papillary carcinoma (USPC) with high versus low HER-2/neu expression. Methods Six primary USPC cell lines, half of which overexpress HER-2/neu at a 3+ level, were evaluated for growth rate and tested for their in vitro sensitivity/resistance to patupilone versus paclitaxel by MTS assays. Quantitative RT-PCR was used to identify potential mechanisms underlying the differential sensitivity/resistance to patupilone versus paclitaxel in primary USPC cell lines. Results Cell lines overexpressing HER-2/neu showed higher proliferation when compared to low HER-2/neu-expressing cell lines. Compared to low-expressing cell lines, high HER-2/neu expressors were significantly more sensitive to patupilone than to paclitaxel ( P < 0.0002). In contrast, there was no appreciable difference in sensitivity to patupilone versus paclitaxel in primary USPC cell lines with low HER-2/neu expression. Higher levels of β-tubulin III (TUBB3) and P-glycoprotein (ABCB1) were detected in USPC cell lines with high versus low HER-2/neu expression ( P < 0.05). Conclusions USPC overexpressing HER-2/neu display greater in vitro sensitivity to patupilone and higher levels of the patupilone molecular target TUBB3 when compared to low HER-2/neu expressors. Due to the adverse prognosis associated with HER-2/neu overexpression in USPC patients, patupilone may represent a promising novel drug to combine to platinum compounds in this subset of aggressive endometrial tumors.

Differential sensitivity to platinum-based chemotherapy in primary uterine serous papillary carcinoma cell lines with high vs low HER-2/neu expression in vitro

We sought to identify effective chemotherapy regimens against uterine serous papillary adenocarcinoma (USPC). Six USPC, half of which overexpress HER-2/neu at 3+ level, were evaluated for growth rate and in vitro sensitivity to 14 single-agent chemotherapies and 5 combinations by ChemoFx (Precision Therapeutics Inc, Pittsburgh, PA). Cell lines overexpressing HER-2/neu showed higher proliferation when compared to low HER-2/neu-expressing cell lines and a lower half maximum inhibitory concentration (IC(50)) when exposed to the majority of single-agent chemotherapies. High HER-2/neu expressors were more sensitive to platinum compounds, manifesting a 5.22-fold decrease in carboplatin-IC(50) (P = .005) and a 5.37-fold decrease in cisplatin-IC(50) (P = .02). When all cell lines were analyzed as a group, chemotherapy agents tested demonstrated lower IC(50) when used in combination than as individual agents. USPC overexpressing HER-2/neu display greater in vitro sensitivity to platinum compounds when compared to low HER-2/neu expressors. Higher proliferative capability rather than increased drug resistance may be responsible for the adverse prognosis associated with HER-2/neu overexpression in USPC.

Abstract 699: Uterine serous papillary carcinomas overexpress human trophoblast-cell-surface marker (Trop-2) and are highly sensitive to immunotherapy with hRS7, a humanized monoclonal anti-Trop-2 antibody

Abstract Purpose: To evaluate the expression of human trophoblast cell-surface marker (Trop-2) and the potential of hRS7, a humanized monoclonal anti-Trop-2 antibody, as a novel therapeutic strategy against Uterine Serous Papillary Carcinoma (USPC), a biologically aggressive and chemotherapy resistant variant of endometrial cancer. Methods: Trop-2 expression was evaluated by real time-PCR and flow cytometry in six primary uterine serous papillary carcinoma cell lines recently characterized in our laboratory. Sensitivity to hRS7 antibody-dependent-cellular-cytotoxicity (ADCC) was tested in standard 5-hrs 51Cr release-assays against primary USPC cell lines expressing different levels of Trop-2. Finally, to investigate the effect of interleukin-2 (IL-2) on hRS7-mediated ADCC, 5-hrs 51Cr assays were also conducted in the presence of low doses of IL-2 (i.e., 50-100 IU/ml). Results: Trop-2 mRNA transcript was significantly overexpressed in 3 out of 6 USPC primary cell lines when compared to normal human endometrial-cells (NEC) [p=0.005]. Consistent with RT-PCR data, high surface expression of Trop-2 was detected by flow cytometry in Trop-2 overexpressing cell lines [i.e., percentage of positive cells = 100% in all 3 positive cell lines, median (minimum-maximum) MFI (mean fluorescence intensity) of 184.2 (62.5-276.2)]. Importantly, while these USPC cell lines were found highly resistant to natural killer dependent cytotoxicity in the absence of the hRS7 antibody (range of killing 1.1% to 12.4%), they showed high sensitivity to hRS7-mediated ADCC in vitro (range of killing 28.2% to 64.4%) (P&amp;lt; 0.001). Incubation with IL-2 in addition to hRS7 further increased the cytotoxic activity against USPC cell lines overexpressing Trop-2 (p= 0.01). Conclusion: Primary USPC cell lines may overexpress Trop-2 at mRNA and protein level and are highly sensitive to hRS7-mediated cytotoxicity in vitro. hRS7 may represent a novel, potentially highly effective therapeutic strategy in patients harbouring advanced, recurrent or metastatic USPC refractory to standard treatment modalities. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 699.

Overexpression of EpCAM in Uterine Serous Papillary Carcinoma: Implications for EpCAM-Specific Immunotherapy With Human Monoclonal Antibody Adecatumumab (MT201)

We evaluated the expression of epithelial cell adhesion molecule (EpCAM) and the potential of MT201 (adecatumumab), a human monoclonal antibody against EpCAM, in uterine serous papillary carcinoma (USPC). EpCAM expression was evaluated by real-time PCR and immunohistochemistry in a total of 56 USPC fresh-frozen biopsies and paraffin-embedded tissues. EpCAM surface expression was also evaluated by flow cytometry and immunohistochemistry in six USPC cell lines. Sensitivity to MT201 antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity was tested against a panel of primary USPC cell lines expressing different levels of EpCAM in standard 5-h (51)Cr release assays. EpCAM transcript was significantly overexpressed in fresh-frozen USPC when compared with normal endometrial cells (NEC). Median (minimum-maximum) copy number was 943.8 (31.5-1568.3) in tumor samples versus 12.9 (1.0-37.0) in NEC (P < 0.001). By immunohistochemistry, EpCAM expression was found in 96% (26 out of 27) of USPC samples with significantly higher expression compared with NECs (P < 0.001). High surface expression of EpCAM was found in 83% (five out of six) of the USPC cell lines tested by flow cytometry. EpCAM-positive cell lines were found highly sensitive to MT201-mediated antibody-dependent cellular cytotoxicity in vitro, whereas primary USPC cell lines were resistant to natural killer cell-dependent cytotoxicity. Human plasma IgG did not significantly inhibit MT201-mediated cytotoxicity against USPC. EpCAM is highly expressed in uterine serous carcinoma at mRNA and protein levels, and primary USPC are highly sensitivity to MT201-mediated cytotoxicity. MT201 might represent a novel therapeutic strategy in patients harboring advanced/recurrent or metastatic USPC refractory to standard treatment modalities.

Serum amyloid A (SAA): a novel biomarker for uterine serous papillary cancer

Background:Uterine serous papillary carcinoma (USPC) is a biologically aggressive variant of endometrial cancer. We investigated the expression of Serum Amyloid A (SAA) and evaluated its potential as a serum biomarker in USPC patients.Methods:SAA gene and protein expression levels were evaluated in USPC and normal endometrial tissues (NEC) by real-time PCR, immunohistochemistry (IHC), flow cytometry and by a sensitive bead-based immunoassay. SAA concentration in 123 serum samples from 51 healthy women, 42 women with benign diseases, and 30 USPC patients were also studied.Results:SAA gene expression levels were significantly higher in USPC when compared with NEC (mean copy number by RT–PCR=162 vs 2.21; P=0.0002). IHC revealed diffuse cytoplasmic SAA protein staining in USPC tissues. High intracellular levels of SAA were identified in primary USPC cell lines evaluated by flow cytometry and SAA was found to be actively secreted in vitro. SAA concentrations (μg ml−1) had a median (95% CIs) of 6.0 (4.0–8.9) in normal healthy females and 6.0 (4.2–8.1) in patients with benign disease (P=0.92). In contrast, SAA values in the serum of USPC patients had a median (95% CI) of 15.6 (9.2–56.2), significantly higher than those in the healthy group (P=0.0005) and benign group (P=0.0006). Receiver operating characteristics (ROC) analysis of serum SAA to classify advanced- and early-stage USPC yielded an area under the ROC curve of 0.837 (P=0.0024).Conclusion:SAA is not only a liver-secreted protein but is also a USPC cell product. SAA may represent a novel biomarker for USPC to assist in staging patients preoperatively, and to monitor early-disease recurrence and response to therapy.

Potential therapeutic activity of adecatumumab (MT201), a fully human monoclonal antibody, against epithelial cell adhesion molecule (EpCAM) in uterine serous papillary carcinoma

e16502 Background: Uterine serous papillary carcinoma (USPC) represents a variant of endometrial cancer characterized by a highly aggressive biologic behavior and inborn resistance to chemotherapy. MT201 is a fully human monoclonal antibody recently developed against epithelial cell adhesion molecule (EpCAM). In this study we have evaluated the potential of MT201 as a novel therapeutic strategy against USPC. Methods: EpCAM expression was evaluated by real time-PCR and immunohistochemistry (IHC) in a total of 54 USPC fresh-frozen biopsies and paraffin embedded tissues. EpCAM surface expression was evaluated by flow cytometry in 6 freshly established USPC cell lines derived from advanced stage USPC patients. Sensitivity to MT201 antibody dependent cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC) was tested in standard 4-hour chromium (51Cr) release cytotoxicity assays. Results: EpCAM transcript was significantly overexpressed in fresh frozen USPC when compared to fresh-frozen normal endometrial cells (NEC) [i.e., mean (minimum-maximum) copy number of 515.4 (31.5–1568.3) in tumor samples versus 8.1 (1.0–25.5) in flash-frozen NEC (p &lt; 0.001)]. By IHC, EpCAM protein expression was found in 96% (26 out of 27) USPC samples and this expression was significantly higher when compared to normal endometrial cells (p &lt; 0.01). High surface expression of EpCAM by flow cytometry was found in 83% (5 out of 6) of the primary USPC cell lines available to this study. Importantly, while primary USPC cell lines were highly resistant to natural killer dependent cytotoxicity in vitro, EpCAM positive cell lines were found highly sensitive to MT201-mediated ADCC. Human serum IgG did inhibit MT201-mediated cytotoxicity against USPC in vitro. Conclusions: These results demonstrate for the first time high EpCAM expression in uterine serous carcinoma at mRNA and protein levels and high sensitivity to MT201-mediated cytotoxicity in vitro by primary USPC cell lines. MT201 might be a novel and attractive therapeutic strategy in patients harboring advanced, recurrent or metastatic USPC refractory to standard treatment modalities. No significant financial relationships to disclose.

Overexpression of claudin‐3 and claudin‐4 receptors in uterine serous papillary carcinoma

Uterine serous papillary carcinoma (USPC) represents a highly aggressive variant of endometrial cancer. Using gene expression profiling, we recently identified high expression of the claudin-3 and claudin-4 receptors in a limited set of USPC. These tight junction proteins represent the low- and high-affinity receptors, respectively, for the cytotoxic Clostridium perfringens enterotoxin (CPE) and are sufficient to mediate CPE binding and trigger subsequent toxin-mediated cytolysis. The potential for targeting this pathway in the treatment of USPC was explored. Claudin-3 and claudin-4 receptor expression was analyzed at the mRNA and protein levels in flash-frozen and formalin-fixed, paraffin-embedded tissue from 20 consecutive USPC patients. The potential of recombinant CPE as a novel therapy against primary, metastatic, and chemotherapy-resistant USPC cell lines was also investigated in vitro. Finally, the in vivo therapeutic effect of sublethal doses of CPE was studied in SCID mouse xenografts harboring subcutaneous and intraperitoneal USPC that expressed claudin-3 and claudin-4. In all, 100% (20 out of 20) of the primary flash-frozen USPC tested overexpressed 1 or both CPE receptors by quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). Membranous immunoreactivity for claudin-4 protein expression was documented in the majority of USPC specimens tested by immunohistochemistry, whereas only a low level of membranous staining was found in normal endometrial control tissue samples. When primary and metastatic short-term USPC cell lines were incubated with different concentrations of CPE in vitro, a dose-dependent cytotoxic effect was demonstrated. In vivo, intratumoral injections of well-tolerated doses of CPE in large subcutaneous USPC xenografts led to large areas of tumor cell necrosis and tumor disappearance in all the treated animals, whereas sublethal intraperitoneal injections of CPE had a significant inhibitory effect on tumor progression, with extended survival of animals harboring chemotherapy-resistant intra-abdominal USPC carcinomatosis. Claudin-3 and claudin-4 receptors may offer promising targets for the use of CPE as a novel type-specific therapy against this highly aggressive and chemotherapy-resistant variant of endometrial cancer.

Overexpression of kallikrein 10 (hK10) in uterine serous papillary carcinomas

Kallikrein 10 is a secreted serine protease recently implicated in the growth and invasion of several human tumors. The goal of this study was to investigate the expression and secretion levels in vitro and in vivo of kallikrein 10 in uterine serous papillary carcinoma, a highly aggressive variant of endometrial tumor. Human kallikrein 10 gene expression levels were evaluated in 11 snap-frozen uterine serous papillary carcinoma biopsies and 6 normal endometrial cell biopsies by real-time polymerase chain reaction. Secretion of kallikrein 10 protein by 10 primary tumor cultures including 3 uterine serous papillary carcinomas, 2 endometrioid carcinomas, and 5 ovarian serous papillary tumors was measured using a sensitive ELISA. Finally, kallikrein 10 concentration in 75 serum and plasma samples from 22 healthy women, 20 women with benign diseases, 21 women with endometrioid carcinomas, and 12 uterine serous papillary carcinoma patients was studied. Kallikrein 10 gene expression levels were significantly higher in uterine serous papillary carcinoma when compared with normal endometrial cell biopsies (mean copy number by real time polymerase chain reaction = 743 versus 1.4; uterine serous papillary carcinoma versus endometrioid carcinoma: P < .02). In vitro kallikrein 10 secretion was detected in all primary uterine serous papillary carcinoma cell lines tested (mean = 2.7 microg/L), and the secretion levels were not significantly different to those found in primary ovarian serous papillary tumor cultures (mean 4.2 microg/L). In contrast, no kallikrein 10 secretion was detectable in primary endometrioid carcinomas. Kallikrein 10 serum and plasma concentrations (microg/L; mean +/- SEM) among normal healthy females (0.6 +/- 0.04), patients with benign diseases (0.6 +/- 0.06), and patients with endometrioid carcinomas (0.7 +/- 0.06) were not significantly different. In contrast, serum and plasma kallikrein 10 values in uterine serous papillary carcinoma patients (1.2 +/- 0.1) were significantly higher than those in the non-cancer group (P = .002), benign group (P = .002), and endometrioid carcinoma patients (P = .005). Kallikrein 10 is highly expressed in uterine serous papillary carcinoma, and it is released in the plasma and serum of uterine serous papillary carcinoma patients. Kallikrein 10 may represent a novel biomarker for uterine serous papillary carcinoma.

High serum levels of interleukin-6 in endometrial carcinoma are associated with uterine serous papillary histology, a highly aggressive and chemotherapy-resistant variant of endometrial cancer

Purpose. To evaluate and compare autocrine expression and production of interleukin-6 (IL-6), a pleiotropic cytokine involved in the resistance to cytotoxic agents and inhibition of anti-tumor immune function in endometrial carcinoma in vitro as well as in vivo. Patients and methods. IL-6 gene expression levels were evaluated in twenty-four primary endometrial tumors including 14 endometrioid carcinomas (EC) and 10 uterine serous papillary carcinoma (USPC) as well as in normal control endometrial cells (NEC) by real-time PCR. Secretion of IL-6 protein by 6 primary endometrial tumor cultures including USPC and EC was measured using a sensitive enzyme-linked immunosorbent assay (ELISA) in vitro. Finally, IL-6 concentration in 71 serum samples including 20 apparently healthy women, 19 women with benign abdominal diseases, 19 women with primary EC, and 13 USPC patients was studied. Results. IL-6 gene expression levels were significantly higher in USPC when compared to EC (mean copy number by RT-PCR = 313 ± 55 vs. 53 ± 11, USPC vs. EC, respectively: P < 0.01). IL-6 serum concentrations between normal healthy females (range 0.01–21.23 pg/ml; mean 3.1 pg/ml) and benign disease patients (range 0.01–95.77 pg/ml; mean 13.07 pg/ml) were not statistically different. In contrast, significantly higher levels of IL-6 were detected in both patients with EC (range 2.86–82.13 pg/ml; mean 20.43 pg/ml) and patients with UPSC (range 16.3–500.1 pg/ml; mean 125.7 pg/ml) when compared to the healthy females ( P < 0.01), with a mean serum IL-6 level in USPC patients 6.1-fold higher when compared to EC patients ( P < 0.03). Accordingly, higher levels of IL-6 secretion were noted in primary USPC cell lines (mean 3121 pg/ml, range between 1099 and 5017 pg/ml/10 5 cells/48 h) when compared to primary EC (mean 88, range between 19 and 112 pg/ml/10 5 cells/48 h) ( P < 0.01) in vitro. Conclusions. IL-6 is highly expressed in USPC, and it is released in high concentration in the serum of USPC patients. IL-6 may be a novel biomarker for USPC. Drugs used to inhibit the expression of IL-6 or the IL-6 signal transduction pathway may potentially be highly beneficial in USPC.

Human Kallikrein 6: A New Potential Serum Biomarker for Uterine Serous Papillary Cancer

The discovery of novel biomarkers might greatly contribute to improve clinical management and outcomes in uterine serous papillary carcinoma (USPC), a highly aggressive variant of endometrial cancer. Human kallikrein 6 (hK6) gene expression levels were evaluated in 29 snap-frozen endometrial biopsies, including 13 USPC, 13 endometrioid carcinomas, and 3 normal endometrial cells by real-time PCR. Secretion of hK6 protein by 14 tumor cultures, including 3 USPC, 3 endometrioid carcinoma, 5 ovarian serous papillary carcinoma, and 3 cervical cancers, was measured using a sensitive ELISA. Finally, hK6 concentration in 79 serum and plasma samples from 22 healthy women, 20 women with benign diseases, 20 women with endometrioid carcinoma, and 17 USPC patients was studied. hK6 gene expression levels were significantly higher in USPC when compared with endometrioid carcinoma (mean copy number by real-time PCR, 1,927 versus 239, USPC versus endometrioid carcinoma; P < 0.01). In vitro hK6 secretion was detected in all primary USPC cell lines tested (mean, 11.5 microg/L) and the secretion levels were similar to those found in primary ovarian serous papillary carcinoma cultures (mean, 9.6 microg/L). In contrast, no hK6 secretion was detectable in primary endometrioid carcinoma and cervical cancer cultures. hK6 serum and plasma concentrations (mean +/- SE) among normal healthy females (2.7 +/- 0.2 microg/L), patients with benign diseases (2.4 +/- 0.2 microg/L), and patients with endometrioid carcinoma (2.6 +/- 0.2 microg/L) were not significantly different. In contrast, serum and plasma hK6 values in USPC patients (6.1 +/- 1.1) were significantly higher than those in the noncancer group (P = 0.006), benign group (P = 0.003), and endometrioid carcinoma patients (P = 0.005). hK6 is highly expressed in USPC and is released in the plasma and serum of USPC patients. hK6 may represent a novel biomarker for USPC for monitoring early disease recurrence and response to therapy.