Long-term follow-up of efficacy and safety of selinexor maintenance treatment in patients with TP53wt advanced or recurrent endometrial cancer: A subgroup analysis of the ENGOT-EN5/GOG-3055/SIENDO study.

OBJECTIVE: To report long-term efficacy and safety of selinexor maintenance therapy in adults with TP53 wild-type (TP53wt) stage IV or recurrent endometrial cancer (EC) who achieved partial remission (PR) or complete remission (CR) following chemotherapy. METHODS: Analysis of the prespecified, exploratory subgroup of patients with TP53wt EC from the phase 3 SIENDO study was performed. Progression-free survival (PFS) benefit in patients with TP53wt EC and across other patient subgroups were exploratory endpoints. Safety and tolerability were also assessed. RESULTS: Of the 263 patients enrolled in the SIENDO trial, 113 patients had TP53wt EC; 70/113 (61.9%) had TP53wt/proficient mismatch repair (pMMR) EC, and 29/113 (25.7%) had TP53wt/deficient mismatch repair (dMMR) EC. As of April 1, 2024, the median PFS (mPFS) for TP53wt patients who received selinexor compared with placebo was 28.4 versus 5.2 months (36.8-month follow-up, HR 0.44; 95% CI 0.27-0.73). A benefit in mPFS was seen with selinexor versus placebo regardless of MMR status (patients with TP53wt/pMMR EC: 39.5 vs 4.9 months, HR 0.36; 95% CI 0.19-0.71; patients with TP53wt/dMMR EC: 13.1 vs 3.7 months, HR 0.49; 95% CI 0.18-1.34). Selinexor treatment was generally manageable, with no new safety signals identified. CONCLUSION: In the phase 3 SIENDO study, selinexor maintenance therapy showed a promising efficacy signal and a manageable safety profile in the prespecified subgroup of patients with TP53wt EC who achieved a PR or CR following chemotherapy. These results are being further evaluated in an ongoing randomized phase 3 trial (NCT05611931).

Proteomic analysis of ascitic extracellular vesicles describes tumour microenvironment and predicts patient survival in ovarian cancer.

High-grade serous carcinoma of the ovary, fallopian tube and peritoneum (HGSC), the most common type of ovarian cancer, ranks among the deadliest malignancies. Many HGSC patients have excess fluid in the peritoneum called ascites. Ascites is a tumour microenvironment (TME) containing various cells, proteins and extracellular vesicles (EVs). We isolated EVs from patients' ascites by orthogonal methods and analyzed them by mass spectrometry. We identified not only a set of 'core ascitic EV-associated proteins' but also defined their subset unique to HGSC ascites. Using single-cell RNA sequencing data, we mapped the origin of HGSC-specific EVs to different types of cells present in ascites. Surprisingly, EVs did not come predominantly from tumour cells but from non-malignant cell types such as macrophages and fibroblasts. Flow cytometry of ascitic cells in combination with analysis of EV protein composition in matched samples showed that analysis of cell type-specific EV markers in HGSC has more substantial prognostic potential than analysis of ascitic cells. To conclude, we provide evidence that proteomic analysis of EVs can define the cellular composition of HGSC TME. This finding opens numerous avenues both for a better understanding of EV's role in tumour promotion/prevention and for improved HGSC diagnostics.

Can Schlafen 11 Help to Stratify Ovarian Cancer Patients Treated with DNA-Damaging Agents?

Platinum-based chemotherapy has been the cornerstone of systemic treatment in ovarian cancer. Since no validated molecular predictive markers have been identified yet, the response to platinum-based chemotherapy has been evaluated clinically, based on platinum-free interval. The new promising marker Schlafen 11 seems to correlate with sensitivity or resistance to DNA-damaging agents, including platinum compounds or PARP inhibitors in various types of cancer. We provide background information about the function of Schlafen 11, its evaluation in tumor tissue, and its prevalence in ovarian cancer. We discuss the current evidence of the correlation of Schlafen 11 expression in ovarian cancer with treatment outcomes and the potential use of Schlafen 11 as the key predictive and prognostic marker that could help to better stratify ovarian cancer patients treated with platinum-based chemotherapy or PARP inhibitors. We also provide perspectives on future directions in the research on this promising marker.

New Trends in the Detection of Gynecological Precancerous Lesions and Early-Stage Cancers.

The prevention and early diagnostics of precancerous stages are key aspects of contemporary oncology. In cervical cancer, well-organized screening and vaccination programs, especially in developed countries, are responsible for the dramatic decline of invasive cancer incidence and mortality. Cytological screening has a long and successful history, and the ongoing implementation of HPV triage with increased sensitivity can further decrease mortality. On the other hand, endometrial and ovarian cancers are characterized by a poor accessibility to specimen collection, which represents a major complication for early diagnostics. Therefore, despite relatively promising data from evaluating the combined effects of genetic variants, population screening does not exist, and the implementation of new biomarkers is, thus, necessary. The introduction of various circulating biomarkers is of potential interest due to the considerable heterogeneity of cancer, as highlighted in this review, which focuses exclusively on the most common tumors of the genital tract, namely, cervical, endometrial, and ovarian cancers. However, it is clearly shown that these malignancies represent different entities that evolve in different ways, and it is therefore necessary to use different methods for their diagnosis and treatment.

Tumor Characteristic Variations between Symptomatic and Asymptomatic Endometrial Cancer.

Endometrial cancer is the most common gynecologic malignancy in Europe and usually diagnosed in its initial stage owing to early symptoms of abnormal bleeding. There is no population screening for this disease, although it can sometimes be accidentally diagnosed in asymptomatic patients. Our study aims to determine differences in clinical and tumor characteristics between an asymptomatic and symptomatic group of patients. This unicentric prospective observational study took place in University Hospital Brno between January 2016 and December 2019. A total of 264 patients met inclusion criteria (26% asymptomatic, 74% with reported symptoms). We did not find a statistically significant difference in clinical characteristics (menopausal status, parity, age, BMI, and serum level of CA 125) between groups. According to ultrasound examination, bleeding tumors were larger (19.5 vs. 12.7 mm, p ≤ 0.001). Definitive histology results indicated more frequent lymphovascular space invasion (p < 0.001), along with deep myometrial (p = 0.001) and cervical (p = 0.002) invasion. There was no difference in advanced stages of the tumor. We did not substantiate statistically significant difference in immunohistochemical profile (estrogen and progesterone receptors, L1 cell adhesion molecule, tumor protein p53), which is relevant for tumor recurrence risk and survival capacity. Our conclusions affirmed that bleeding occurs more often among patients with local tumor invasion into the myometrium and cervical stroma. Final International Federation of Gynecology and Obstetrics (FIGO) stage, histology, and immunohistochemical characteristics do not significantly affect symptom appearance.

The Clinical Significance of DJ1 and L1CAM Serum Level Monitoring in Patients with Endometrial Cancer.

Circulating tumor markers are not routinely used in patients with endometrial cancer (EC). This pilot study evaluated the role of monitoring new biomarkers DJ1 and L1CAM, in correlation with CA125 and HE4, for the effects of anticancer treatment and preoperative management in EC patients. Serial serum levels of DJ1, L1CAM, CA125 and HE4 were collected in 65 enrolled patients. Serum DJ1, L1CAM, CA125 and HE4 levels were significantly higher at the time of diagnosis compared to those measured during follow-up (FU). In patients with recurrent disease, serum DJ1, CA125 and HE4 levels were significantly higher at the time of recurrence compared to levels in disease-free patients. Serum L1CAM levels were also higher in patients with recurrence but without reaching statistical significance. While DJ1 levels were not affected by any of the observed patient-related characteristics, L1CAM levels were significantly higher in patients with age ≥60 years who were overweight. At the time of EC diagnosis, DJ1 and L1CAM serum levels did not correlate with stage, histological type or risk of recurrence. This is a preliminary description of the potential of serial DJ1 and L1CAM serum level measurement for monitoring the effects of treatment in EC patients.

The cutoff for estrogen and progesterone receptor expression in endometrial cancer revisited: a European Network for Individualized Treatment of Endometrial Cancer collaboration study.

There is no consensus on the cutoff for positivity of estrogen receptor (ER) and progesterone receptor (PR) in endometrial cancer (EC). Therefore, we determined the cutoff value for ER and PR expression with the strongest prognostic impact on the outcome. Immunohistochemical expression of ER and PR was scored as a percentage of positive EC cell nuclei. Cutoff values were related to disease-specific survival (DSS) and disease-free survival (DFS) using sensitivity, specificity, and multivariable regression analysis. The results were validated in an independent cohort. The study cohort (n = 527) included 82% of grade 1-2 and 18% of grade 3 EC. Specificity for DSS and DFS was highest for the cutoff values of 1-30%. Sensitivity was highest for the cutoff values of 80-90%. ER and PR expression were independent markers for DSS at cutoff values of 10% and 80%. Consequently, three subgroups with distinct clinical outcomes were identified: 0-10% of ER/PR expression with, unfavorable outcome (5-year DSS = 75.9-83.3%); 20-80% of ER/PR expression with, intermediate outcome (5-year DSS = 93.0-93.9%); and 90-100% of ER/PR expression with, favorable outcome (5-year DSS = 97.8-100%). The association between ER/PR subgroups and outcomes was confirmed in the validation cohort (n = 265). We propose classification of ER and PR expression based on a high-risk (0-10%), intermediate-risk (20-80%), and low-risk (90-100%) group.

Does an Endometrial Cancer Diagnosis among Asymptomatic Patients Improve Prognosis?

BACKGROUND: Endometrial cancer is the most common gynecological malignancy in developed countries with no screening available. There is still a tendency to provide invasive bioptic verification in asymptomatic women with abnormal ultrasound findings to diagnose carcinoma in a preclinical phase; even though, it is not supported by European guidelines. Our goal was to determine DFS (disease-free survival), OS (overall survival), and DSS (disease-specific survival) differences between symptom-free and symptomatic (bleeding, or spotting) endometrial cancer patients with similar stage and tumor/clinical characteristics. METHODS: All of our patients with endometrial cancer following surgical treatment between 2006 and 2019 were assessed, evaluating risk factors for recurrence and death while focusing on bleeding using univariable and multivariable analysis. RESULTS: 625 patients meeting the inclusion criteria were divided into asymptomatic (n = 144, 23%) and symptomatic (n = 481, 77%) groups. The median follow-up was 3.6 years. Using univariable analysis, symptomatic patients had a three times higher risk of recurrence (HR 3.1 (95% Cl 1.24-7.77), p = 0.016). OS (HR 1.35 (0.84-2.19), p = 0.219) and DSS (HR 1.66 (0.64-4.28), p = 0.3) were slightly worse without reaching statistical significance. In our multivariable analysis, symptomatology was deemed completely insignificant in all monitored parameters (DFS: HR 2.03 (0.79-5.24), p = 0.144; OS: HR 0.72 (0.43-1.21), p = 0.216). CONCLUSIONS: The symptomatic endometrial cancer patients risk factor of earlier recurrence and death is insignificantly higher when compared with the asymptomatic cohort. However, multivariable analysis verifies that prognosis worsens with other clinically relevant parameters, not by symptomatology itself. In terms of survival outcome in EC patients, we recognized symptomatology as a non-significant marker for the patient's prognosis.

Preoperative risk stratification in endometrial cancer (ENDORISK) by a Bayesian network model: A development and validation study.

BACKGROUND: Bayesian networks (BNs) are machine-learning-based computational models that visualize causal relationships and provide insight into the processes underlying disease progression, closely resembling clinical decision-making. Preoperative identification of patients at risk for lymph node metastasis (LNM) is challenging in endometrial cancer, and although several biomarkers are related to LNM, none of them are incorporated in clinical practice. The aim of this study was to develop and externally validate a preoperative BN to predict LNM and outcome in endometrial cancer patients. METHODS AND FINDINGS: Within the European Network for Individualized Treatment of Endometrial Cancer (ENITEC), we performed a retrospective multicenter cohort study including 763 patients, median age 65 years (interquartile range [IQR] 58-71), surgically treated for endometrial cancer between February 1995 and August 2013 at one of the 10 participating European hospitals. A BN was developed using score-based machine learning in addition to expert knowledge. Our main outcome measures were LNM and 5-year disease-specific survival (DSS). Preoperative clinical, histopathological, and molecular biomarkers were included in the network. External validation was performed using 2 prospective study cohorts: the Molecular Markers in Treatment in Endometrial Cancer (MoMaTEC) study cohort, including 446 Norwegian patients, median age 64 years (IQR 59-74), treated between May 2001 and 2010; and the PIpelle Prospective ENDOmetrial carcinoma (PIPENDO) study cohort, including 384 Dutch patients, median age 66 years (IQR 60-73), treated between September 2011 and December 2013. A BN called ENDORISK (preoperative risk stratification in endometrial cancer) was developed including the following predictors: preoperative tumor grade; immunohistochemical expression of estrogen receptor (ER), progesterone receptor (PR), p53, and L1 cell adhesion molecule (L1CAM); cancer antigen 125 serum level; thrombocyte count; imaging results on lymphadenopathy; and cervical cytology. In the MoMaTEC cohort, the area under the curve (AUC) was 0.82 (95% confidence interval [CI] 0.76-0.88) for LNM and 0.82 (95% CI 0.77-0.87) for 5-year DSS. In the PIPENDO cohort, the AUC for 5-year DSS was 0.84 (95% CI 0.78-0.90). The network was well-calibrated. In the MoMaTEC cohort, 249 patients (55.8%) were classified with <5% risk of LNM, with a false-negative rate of 1.6%. A limitation of the study is the use of imputation to correct for missing predictor variables in the development cohort and the retrospective study design. CONCLUSIONS: In this study, we illustrated how BNs can be used for individualizing clinical decision-making in oncology by incorporating easily accessible and multimodal biomarkers. The network shows the complex interactions underlying the carcinogenetic process of endometrial cancer by its graphical representation. A prospective feasibility study will be needed prior to implementation in the clinic.

WNT signaling inducing activity in ascites predicts poor outcome in ovarian cancer.

High grade serous carcinoma of the ovary, fallopian tube, and peritoneum (HGSC) is the deadliest gynecological disease which results in a five-year survival rate of 30% or less. HGSC is characterized by the early and rapid development of metastases accompanied by a high frequency of ascites i.e. the pathological accumulation of fluid in peritoneum. Ascites constitute a complex tumor microenvironment and contribute to disease progression by largely unknown mechanisms. Methods: Malignant ascites obtained from HGSC patients who had undergone cytoreductive surgery were tested for their ability to induce WNT signaling in the Kuramochi cell line, a novel and clinically relevant in vitro model of HGSC. Next, cancer spheroids (the main form of metastatic cancer cells in ascites) were evaluated with respect to WNT signaling. Kuramochi cells were used to determine the role of individual WNT signaling branches in the adoption of metastatic stem cell-like behavior by HGSC cells. Furthermore, we analyzed genomic and transcriptomic data on WNT/Planar Cell Polarity (PCP) components retrieved from public cancer databases and corroborated with primary patient samples and validated antibodies on the protein level. Results: We have shown that ascites are capable of inducing WNT signaling in primary HGSC cells and HGSC cell line, Kuramochi. Importantly, patients whose ascites cannot activate WNT pathway present with less aggressive disease and a considerably better outcome including overall survival (OS). Functionally, the activation of non-canonical WNT/PCP signaling by WNT5A (and not canonical WNT/ß-catenin signaling by WNT3A) promoted the metastatic stem-cell (metSC) like behavior (i.e. self-renewal, migration, and invasion) of HGSC cells. The pharmacological inhibition of casein kinase 1 (CK1) as well as genetic ablation (dishevelled 3 knock out) of the pathway blocked the WNT5A-induced effect. Additionally, WNT/PCP pathway components were differentially expressed between healthy and tumor tissue as well as between the primary tumor and metastases. Additionally, ascites which activated WNT/PCP signaling contained the typical WNT/PCP ligand WNT5A and interestingly, patients with high levels of WNT5A protein in their ascites exhibited poor progression-free survival (PFS) and OS in comparison to patients with low or undetectable ascitic WNT5A. Together, our results suggest the existence of a positive feedback loop between tumor cells producing WNT ligands and ascites that distribute WNT activity to cancer cells in the peritoneum, in order to promote their pro-metastatic features and drive HGSC progression. Conclusions: Our results highlight the role of WNT/PCP signaling in ovarian cancerogenesis, indicate a possible therapeutic potential of CK1 inhibitors for HGSC, and strongly suggest that the detection of WNT pathway inducing activity ascites (or WNT5A levels in ascites as a surrogate marker) could be a novel prognostic tool for HGSC patients.

A Novel Approach to Preoperative Risk Stratification in Endometrial Cancer: The Added Value of Immunohistochemical Markers.

Background: The current model used to preoperatively stratify endometrial cancer (EC) patients into low- and high-risk groups is based on histotype, grade, and imaging method and is not optimal. Our study aims to prove whether a new model incorporating immunohistochemical markers, L1CAM, ER, PR, p53, obtained from preoperative biopsy could help refine stratification and thus the choice of adequate surgical extent and appropriate adjuvant treatment. Materials and Methods: The following data were prospectively collected from patients operated for EC from January 2016 through August 2018: age, pre- and post-operative histology, grade, lymphovascular space invasion, L1CAM, ER, PR, p53, imaging parameters obtained from ultrasound, CT chest/abdomen, final FIGO stage, and current decision model (based on histology, grade, imaging method). Results: In total, 132 patients were enrolled. The current model revealed 48% sensitivity and 89% specificity for high-risk group determination. In myometrial invasion >50%, lower levels of ER (p = 0.024), PR (0.048), and higher levels of L1CAM (p = 0.001) were observed; in cervical involvement a higher expression of L1CAM (p = 0.001), lower PR (p = 0.014); in tumors with positive LVSI, higher L1CAM (p = 0.014); in cases with positive LN, lower expression of ER/PR (p < 0.001), higher L1CAM (p = 0.002) and frequent mutation of p53 (p = 0.008). Cut-offs for determination of high-risk tumors were established: ER <78% (p = 0.001), PR <88% (p = 0.008), and L1CAM ≥4% (p < 0.001). The positive predictive values (PPV) for ER, PR, and L1CAM were 87% (60.8-96.5%), 63% (52.1-72.8%), 83% (70.5-90.8%); the negative predictive values (NPV) for each marker were as follows: 59% (54.5-63.4%), 65% (55.6-74.0%), and 77% (67.3-84.2%). Mutation of p53 revealed PPV 94% (67.4-99.1%) and NPV 61% (56.1-66.3%). When immunohistochemical markers were included into the current diagnostic model, sensitivity improved (48.4 vs. 75.8%, p < 0.001). PPV was similar for both methods, while NPV (i.e., the probability of extremely low risk in negative test cases) was improved (66 vs. 78.9%, p < 0.001). Conclusion: We proved superiority of new proposed model using immunohistochemical markers over standard clinical practice and that new proposed model increases accuracy of prognosis prediction. We propose wider implementation and validation of the proposed model.

Struma ovarii - ultrasound features of a rare tumor mimicking ovarian cancer.

AIMS: To describe the ultrasound features of benign struma ovarii that often mimic ovarian cancer in the background of complex clinical and histopathological pictures. MATERIAL AND METHODS: We retrospectively identified patients with histologically confirmed benign struma ovarii, treated in our institution between 2003-2016 with complete imaging, clinical, nd histopathological data available. Ultrasound findings were drawn from images, and reports using terms and definitions of the International Ovarian Tumor Analysis group and pattern recognition description was applied. RESULTS: In all, 19 patients were identified; 10 with pure and 9 with impure struma. Median age was 47 (range 24-69); 10 (53%) were premenopausal. Only four (21%) patients presented with pain, others were asymptomatic. Using pattern recognition, 74% strumas (14/19) were uni-/multilocular solid or solid tumors. The solid components were roundish with smooth contours. Six struma pearls were detected. The subjective color score was moderate or abundant in the majority of solid components. Only 5 (26%) tumors were purely cystic. CONCLUSIONS: The ultrasound characteristics differ widely from typical mature ovarian teratoma. Features such as, solid roundish components with smooth contours, struma pearls, acoustic shadowing and occasionally signs of dermoid are clues and may help preoperatively to differentiate benign struma from malignant adnexal lesions.

Brenner tumor of the ovary - ultrasound features and clinical management of a rare ovarian tumor mimicking ovarian cancer.

OBJECTIVES: To describe the ultrasound features of benign Brenner tumor in the background of complex clinical and histopathological pictures. MATERIAL AND METHODS: We retrospectively identified patients with histologically confirmed benign Brenner tumor of the ovary who were treated in our institution in 2003-2016, and for whom complete imaging, clinical, perioperative and histopathological data were available in the database. Ultrasound findings were drawn from images and reports using terms and definitions of the International Ovarian Tumor Analysis group and pattern recognition description was applied. RESULTS: Twenty-three patients were identified, most postmenopausal and asymptomatic. On ultrasound, 19/23 tumors were found unilaterally, 4/23 bilaterally, and 82% of tumors were detected in the left ovary. Most Brenner tumors (16/23) contained solid components and revealed no or minimal blood flow by subjective color score upon Doppler examination (19/23, 83%). Calcifications with shadowing were observed in 57% of all Brenner tumors and in 81% of tumors containing solid components. The complex appearance of the tumor misled the sonographers to describe the mass as malignant in 9 cases (39%), and frozen section was performed perioperatively. Surgery was performed via laparoscopy in 11 (48%) and via laparotomy in 12 (52%) cases. CONCLUSIONS: The complexity of the ultrasound picture, consisting of features like calcifications with acoustic shadowing, a poorly vascularized solid mass, and a left-sided localization could be signs of a benign Brenner tumor and could preop-eratively help to differentiate between benign and malignant tumor.

Importance of Preoperative Knowledge of the Biomarker HE4 in Early-stage Endometrial Cancer Regarding Surgical Management.

AIM: To analyze the utility of HE4 assessment in preoperative management of patients with early-stage endometrial cancer for stratification into low-risk and high-risk groups. PATIENTS AND METHODS: The following data were prospectively collected from patients operated for endometrial cancer from 05/2012 till 9/2016; age, HE4, CA125, expert ultrasound examination of the pelvis, histotype, grade, FIGO stage. RESULTS: In total, 124 patients were enrolled. A cut-off of ≥113 pmol/l HE4 demonstrated 40.3% sensitivity and 83.9% specificity for detection of high-risk patients. Correlations of HE4 with age (p<0.001), depth of myometrial invasion (p=0.001), clinical stage of the disease according to ultrasound - T1a vs. T1b (63.6 pmol/l vs. 110.6 pmol/l, p<0.001) were found. However, no correlation of HE4 with lymph node invasion (p=0.07) and tumor grade (p=0.212) was identified. CONCLUSION: HE4 levels correspond to clinical and FIGO stage of the disease. The sensitivity and specificity does not reach the transvaginal ultrasound results in preoperative assessment of the extent of the disease. Combination of HE4 with ultrasound does not improve the stratification of patients into low-risk and high-risk groups. Preoperative assessment of HE4 is useful providing no imaging method is available.

Serous tubal intraepithelial carcinoma (STIC) - clinical impact and management.

INTRODUCTION: Serous tubal intraepithelial carcinoma (STIC) is most likely precursor lesion of the most part of high-grade serous pelvis carcinomas, carcinosarcoma and undifferentiated carcinoma with incidence of 0.6% to 7% in BRCA carriers or women with strong family history of breast or ovarian carcinoma. STIC is a pathomorphologically and immunohistochemically detectable lesion which biological significance and clinical relevance is unknown. Areas covered: We investigate methods of STIC diagnostics and we present an overview of recent studies and available knowledge on surgical management, adjuvant chemotherapy and subsequent follow-up procedure in women with an isolated STIC. Expert commentary: Patients found to have an incidental STIC lesion should be referred for screening of BRCA1/2 mutation. In absence of an invasive disease, follow-up of patient remains a reasonable choice. A rational scheme should include check-ups every 6 months consisting of gynecological examinations, CA 125 and/or HE4 and pelvic ultrasound examination by an expert sonographer.

Gene expression of somatostatin receptor 4 predicts clinical outcome of patients with metastatic neuroendocrine tumors treated with somatostatin analogs.

Somatostatin analogs (SSA) are the standard diagnostic and treatment tools in the clinical management of patients with neuroendocrine tumors (NETs) expressing somatostatin receptors (SSTRs). Although symptomatic and biochemical control is obtained with SSA in the majority of functional NETs, antineoplastic effects of SSA are partial and of limited duration. The aim of this study was to quantify expression levels of five SSTR subtypes (SSTR1-SSTR5) and correlate them with the clinical outcomes of patients with NETs who underwent SSA therapy. The expression levels were analyzed using real-time polymerase chain reaction in a series of 22 metastatic NETs with a median time of 10 months on the SSA therapy (range 2-82 months). The median duration of disease stabilization in patients who developed progression (n = 14) was 9 months (range 3-92 months). The median survival period for all patients was 44 months (range 3-175 months). According to RECIST criteria, one (5%) partial objective tumor response was obtained, disease stabilization was achieved in 10 (45%) patients, and progressive disease was observed in 11 (50%). Analysis of mRNA expression of the SSTR subtypes showed that SSTR2 and SSTR5 were expressed in all of the studied NETs; SSTR1 and SSTR4 in all but 3 tumors (86%); and SSTR3 in only 10 NETs (49%). Interestingly, our preliminary data suggest that only the levels of SSTR4, though it has the lowest affinity for SSA of all SSTR subtypes, were significantly associated with the stabilization of disease during SSA therapy (p = 0.0357). These levels correlated with time to progression (p = 0.0015) and overall survival (p = 0.0017) in NET patients.