Singular Value Decomposition-Based Penalized Multinomial Regression for Classifying Imbalanced Medulloblastoma Subgroups Using Methylation Data.

Medulloblastoma (MB) is a molecularly heterogeneous brain malignancy with large differences in clinical presentation. According to genomic studies, there are at least four distinct molecular subgroups of MB: sonic hedgehog (SHH), wingless/INT (WNT), Group 3, and Group 4. The treatment and outcomes depend on appropriate classification. It is difficult for the classification algorithms to identify these subgroups from an imbalanced MB genomic data set, where the distribution of samples among the MB subgroups may not be equal. To overcome this problem, we used singular value decomposition (SVD) and group lasso techniques to find DNA methylation probe features that maximize the separation between the different imbalanced MB subgroups. We used multinomial regression as a classification method to classify the four different molecular subgroups of MB using the reduced DNA methylation data. Coordinate descent is used to solve our loss function associated with the group lasso, which promotes sparsity. By using SVD, we were able to reduce the 321,174 probe features to just 200 features. Less than 40 features were successfully selected after applying the group lasso, which we then used as predictors for our classification models. Our proposed method achieved an average overall accuracy of 99% based on fivefold cross-validation technique. Our approach produces improved classification performance compared with the state-of-the-art methods for classifying MB molecular subgroups.

Clinicopathological profile and management of thyroid carcinoma: a Sub-Saharan country experience.

BACKGROUND: In Sudan, there is limited knowledge on the epidemiology, clinical characteristics and pathological patterns of thyroid cancer. To address this shortcoming, we studied the clinical, pathological and treatment patterns of thyroid cancer at the National Cancer Institute ‒ University of Gezira (NCI-UG), Sudan. METHODS: We performed a retrospective health facility-based study of patients with thyroid cancer who were treated at NCI-UG from January 2009 to December 2017. RESULTS: A total of 139 patients with thyroid cancer were identified during the study period. Tumors were more common among women (69%). Goiter was the main presenting symptom (85%). The most common type of thyroid cancer was follicular carcinoma (41%), followed by papillary carcinoma (24%), then anaplastic carcinoma (20%). The mean age of the women was 56.3 years (SD ± 14.7), compared to 52.5 years (SD ± 16.6) for the men. The frequencies of stage I, II, III, and IV were 17%, 22%, 16%, and 45%, respectively. Different types of thyroidectomies were performed in 79% of the cases, lobectomy in 4%, and no surgery in 17%. Only 28% of the cases received radioactive iodine. Palliative chemotherapy and radiotherapy were prescribed to 17% and 37% of the cases, respectively. CONCLUSION: Thyroid cancer is more prevalent among women and most patients present at later stages. The dominance of follicular type suggests that the majority of this population is iodine-deficient.

Formulation of Lipid-Based Nanoparticles for Simultaneous Delivery of Lapatinib and Anti-Survivin siRNA for HER2+ Breast Cancer Treatment.

In this work, lipid-based nanoparticles (LBNP) were designed to combine tyrosine kinase inhibitor (TKI) Lapatinib (LAPA) with siRNA directed against apoptosis inhibitor protein Survivin (siSurvivin) in an injectable form. This nanosystem is based on lipid nanocapsules (LNCs) coated with a cationic polymeric shell composed of chitosan grafted through a transacylation reaction. The hydrophobic LAPA is solubilized in the inner oily core, while hydrophilic siRNA is associated electrostatically onto the nanocarrier's surface. The co-loaded LBNP showed a narrow size distribution (polydispersity index (PDI) < 0.3), a size of 130 nm, and a slightly positive zeta potential (+21 mV). LAPA and siRNA were loaded in LBNP at a high rate of >90% (10.6 mM) and 100% (4.6 µM), respectively. The siRNA-LAPA_LBNP was readily uptaken by the human epidermal growth factor receptor 2 overexpressed (HER2+) breast cancer cell line SK-BR-3. Moreover, the cytotoxicity studies confirmed that the blank chitosan decorated LBNP is not toxic to the cells with the tested concentrations, which correspond to LAPA concentrations from 1 to 10 µM, at different incubation times up to 96 h. Furthermore, siCtrl.-LAPA_LBNP had a more cytotoxic effect than Lapatinib salt, while siSurvivin-LAPA_LBNP had a significant synergistic cytotoxic effect compared to siCtrl.-LAPA_LBNP. All these findings suggested that the developed modified LBNP could potentiate anti-Survivin siRNA and LAPA anti-cancer activity.

Combination of Nanovectorized siRNA Directed against Survivin with Doxorubicin for Efficient Anti-Cancer Activity in HER2+ Breast Cancer Cells.

According to Globocan 2020, breast cancer is considered one of the most common cancers affecting women and is one of the leading causes of death in over 100 countries. The available classical treatment options do not always give satisfactory outcomes, and some patients develop resistance to these treatments. This study aims to investigate the combination of nanovectorized siRNA directed against anti-apoptotic protein Survivin (siSurvivin) by targeted stealth magnetic siRNA nanovectors (TS-MSN), designed in our lab, with Doxorubicin (DOX), as an option for HER2+ breast cancer treatment. The hypothesis is that the pretreatment of the HER2+ breast cancer cell line SK-BR-3 with siSurvivin will induce apoptosis in the cancer cells and enhance the therapeutic efficacy of DOX, allowing a dose reduction of DOX and hence a reduction of potential side effects. TS-MSN are based on superparamagnetic iron oxide nanoparticles (SPIONs) covalently coupled with a fluorophore sulfocyanine-5 and polyethylene glycol 5000 (PEG5000) and functionalized with single-chain variable fragments (scFv) of an antibody targeting the HER2 membrane receptor. These covalently functionalized SPIONs are then complexed via electrostatic interactions with therapeutic siRNA and the cationic polymers, chitosan, and poly-L-arginine. TS-MSNsiSurvivin had an average size of 144 ± 30 nm, a PDI of 0.3, and a slightly positive zeta potential value of 10.56 ± 05.70 mV. The agarose gel electrophoresis assay confirmed that the siRNA is well-complexed into TS-MSN without leakage, as no free siRNA was detected. Moreover, siRNA in TS-MSN was protected from RNAse A degradation for up to 6 h at 37 °C. Formulations of TS-MSN with siSurvivin demonstrated in vitro gene knockdown up to 89% in the HER2+ breast cancer cell line SK-BR-3. Furthermore, qRT-PCR confirmed a significant Survivin mRNA relative expression inhibition (about 50%) compared to control siRNA or untreated cells. A combination protocol was evaluated between TS-MSN and Doxorubicin (DOX) for the first time. Therefore, SK-BR-3 cells were pretreated with TS-MSN formulated with siSurvivin at 50 nM for 24 h alone, before a DOX treatment at a concentration of 0.5 µM (corresponding to the IC50) was added for 48 h. The MTT cytotoxicity tests, performed after 72 h of treatment, revealed that the combination had a significant synergistic cytotoxic effect on SK-BR-3 cells compared to monotherapies or untreated cells. We confirmed that pretreatment of cells with siSurvivin potentializes the cytotoxic effect of DOX as an alternative approach for treating HER2+ breast cancer. In conclusion, a combination of anti-Survivin siRNA and DOX would be a good alternative in HER2+ breast cancer therapy.

Nanoparticles design considerations to co-deliver nucleic acids and anti-cancer drugs for chemoresistance reversal.

Chemoresistance and hence the consequent treatment failure is considerably challenging in clinical cancer therapeutics. The understanding of the genetic variations in chemoresistance acquisition encouraged the use of gene modulatory approaches to restore anti-cancer drug efficacy. Many smart nanoparticles are designed and optimized to mediate combinational therapy between nucleic acid and anti-cancer drugs. This review aims to define a rational design of such co-loaded nanocarriers with the aim of chemoresistance reversal at various cellular levels to improve the therapeutic outcome of anticancer treatment. Going through the principles of therapeutics loading, physicochemical characteristics tuning, and different nanocarrier modifications, also looking at combination effectiveness on chemosensitivity restoration. Up to now, these emerging nanocarriers are in development status but are expected to introduce outstanding outcomes.

Relapse-free survival in Sudanese women with non-metastatic breast cancer.

Background: Breast cancer (BC) is the most frequently diagnosed cancer and a major cause of cancer mortality in Sudan. However, there is lack of data related to BC relapse. Therefore, this study was undertaken to estimate the 5-year relapse free survival (RFS) rate and factors related to BC relapse in Sudanese women with non-metastatic BC. Methods: Data of BC women with BC diagnosed and treated at the National Cancer Institute-University of Gezira during 2012 were retrieved from medical records. The cases were followed-up through hospital records and telephone contact. Survival functions were calculated using Kaplan-Meier method and compared by log-rank test. The prognostic factors were tested using univariate and multivariable Cox regression analyses. Results: We included 168 women with median age of 45 years (range, 22-83 years). 53.5%of women had stage III at time of diagnosis, whereas 4.2% and 42.3% of women presented with stage I and stage II, respectively. At the end of 5 years follow-up, with median follow-up period of 64 months, 94 (56.0%) women were alive in remission, 11 (6.5%) were alive with BC relapse, 49 (29.2%) were dead, and survival status was unknown in 14 (8.3%) women. Most of the occurred relapses were distant relapses. The 5-year RFS was 59%. The independent predictors of relapse were: larger primary tumor size (HR:1.84, 95% CI: 1.54-5.48, p=0.018); involved axillary lymph nodes with tumour (HR:  2.91, 95% CI:  1.53-7.91, p=0.001); not receiving adjuvant radiotherapy (HR: 2.2, 95% CI: 1.22-3.95, p=0.009); and not receiving hormone therapy (HR: 1.67, 95% CI: 1.01-2.76, p= 0.046). Conclusion: We found a high risk of BC relapse in our resource-constrained settings. Advanced stages, not receiving adjuvant radiotherapy, and not receiving adjuvant hormone therapy were independent predictors associated with worse 5-year RFS. Therefore, enhancing the early diagnosis of BC and improving timely access to appropriate treatments represent key approaches to achieving better treatment outcomes.

Survival Outcomes of Breast Cancer in Sudanese Women: A Hospital-Based Study.

PURPOSE: Breast cancer (BC) is the leading malignancy among Sudanese women. Yet, data on survival are limited. This study aimed to determine 5-year overall survival (OS) of BC in Sudanese women, and identify prognostic demographic and clinicopathologic factors. PATIENTS AND METHODS: A hospital-based retrospective study was conducted by reviewing data of women with BC diagnosed and treated at the National Cancer Institute-University of Gezira during 2012, and followed up to end of August 2018. Data were retrieved from medical records and analyzed, OS was determined, and the prognostic factors were explored. RESULTS: A total of 225 cases were recruited. The median age at presentation was 45 years (range, 22-85 years). Clinical stage I, II, III, and IV represented 3.1%, 31.6%, 48%, and 17.3%, respectively. Most women (81.3%) were treated with curative intent. Of those, 25.1% received neoadjuvant chemotherapy. Mastectomy was the commonest (61.7%) type of surgery. The median follow-up period was 59.8 months with mean OS time of 55.7 months. The 5-year cumulative survival rate was 58%. The 5-year OS rates for stages I, II, III, and IV were 71.5%, 82.4%, 56.5%, and 8.4%, respectively. For lymph node (LN)-positive cases, 5-year OS rate was 63% and for LN-negative was 83.5%. Presenting with advanced-stage disease and positive LN status associated with short OS times (P < .005). CONCLUSION: OS of women with BC in Central Sudan is worse than in the developed world, but similar to African countries. Our findings indicate that advanced stage at diagnosis and lymph nodal involvement are strong predictors of short survival times. Raising awareness and introducing early detection programs are critical for better survival of these patients.

C-reactive protein is associated with low-density lipoprotein cholesterol and obesity in type 2 diabetic Sudanese.

BACKGROUND: Type 2 diabetes is emerging in Sudan and is associated with obesity. Deregulated lipid metabolism and inflammatory states are suggested risk factors for cardiovascular disease, which is a leading cause of diabetic death. This study aimed to investigate C-reactive protein (CRP) levels and the lipid profile in type 2 diabetic adult Sudanese compared with nondiabetics, and to test their associations with other characteristics. METHODS: A cross-sectional study including 70 diabetics and 40 nondiabetics was conducted. Anthropometric measurements were assessed, and demographic and medical data were obtained using a structured questionnaire. Blood specimens were collected and biochemical parameters were analyzed applying standard methods. RESULTS: CRP and triglycerides were significantly higher in the diabetic group (P<0.001 and P=0.01, respectively). Differences in total cholesterol, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were not statistically significant between the diabetic and nondiabetic groups. In the diabetic group, correlation analysis revealed that the CRP level had a significant positive correlation with LDL-C (r=0.255, P=0.034) and body mass index (r=0.29, P=0.016). Body mass index showed a significant positive correlation with triglycerides (r=0.386, P=0.001). Within the lipid parameters, a number of significant correlations were observed. Elevated levels of CRP, LDL-C, and triglycerides were markedly more prevalent in the diabetic group of patients. Diabetics showed significantly higher CRP levels compared with nondiabetics (odds ratio 5.56, P=0.001). CONCLUSION: The high prevalence of obesity among diabetics, together with elevated levels of triglycerides and CRP, suggest coexistence of dyslipidemia and inflammation in diabetes. Our findings emphasize that diabetics were 5.6 times more likely to have high CRP levels than nondiabetics; as CRP is a predictor of cardiovascular disease risk, it can be recognized that diabetics are at more risk of cardiovascular disease than nondiabetics. Considering evaluation of CRP together with the lipid profile in prediction of cardiovascular disease risk in Sudanese diabetics should be further tested in large-scale studies.

Down-regulation of the microRNA processing enzyme Dicer is a prognostic factor in human colorectal cancer.

AIMS: MicroRNA deregulation is a key feature of cancer; however, the molecular mechanisms underlying deregulation are unknown. Dicer is a central enzyme in microRNA processing essential for production of mature microRNAs which, in turn, regulate gene expression post-transcription. The aim was to investigate whether Dicer expression in colorectal cancer correlates with conventional clinicopathological parameters and patient survival. METHODS AND RESULTS: Immunohistochemical staining for Dicer was performed on tissue microarrays of 331 samples from patients with primary colorectal carcinoma. A subset (19.6%) of colorectal carcinomas was negative for Dicer. Dicer protein expression was associated significantly and inversely with disease (WHO) stage (P = 0.029), tumour grade (P = 0.001), tumour stage (P = 0.022) and nodal metastasis (P = 0.004). Negative expression of Dicer correlated significantly with shortened overall survival (P = 0.007) and was independent of other prognostic factors in multivariate analysis (Cox regression: P = 0.035, hazard ratio=1.6; 95% confidence interval 1.034-2.513). Additionally, in univariate analysis, an association of Dicer expression with survival was observed in subsets of patients without metastasis (P = 0.026), older patients (P = 0.005) and patients with advanced tumour stage (P = 0.022). CONCLUSION: Dicer deregulation is linked significantly to adverse disease state and decreased overall survival in colorectal cancer. Our data suggest that reduced Dicer expression might contribute to tumour progression in colorectal cancer.

Prognostic significance of Dicer expression in ovarian cancer-link to global microRNA changes and oestrogen receptor expression.

MicroRNA (miRNA) deregulation is a hallmark of human cancer. However, the mechanisms underlying miRNA alteration and the specific role of proteins involved in miRNA processing remains to be elucidated. Dicer is a key enzyme in the miRNA processing pathway that is essential for the production of mature miRNAs from their precursors. We tested the hypothesis that Dicer has biological and clinical relevance in ovarian cancer, using a range of methods including in vitro manipulation of Dicer expression. We observed down-regulation of Dicer in a subgroup of ovarian carcinomas, and found that decreased Dicer expression correlates significantly with reduced patient survival in serous cancers and advanced disease stages. Moreover, microarray and functional analysis suggest that reduced Dicer expression is connected with a global down-regulation of the microRNAome and with gene expression changes, particularly reduced expression of oestrogen receptor (ER) mRNA and protein in tumour tissue and in cell culture. Our data suggest a common mechanism for miRNAs changes by alterations in the basic machinery controlling miRNA biogenesis, of which Dicer is a central enzyme. These alterations of miRNA processing are of prognostic value and may play a role in the molecular pathogenesis of ovarian carcinoma and, possibly, other tumours. Knowledge of these molecular pathways may help toward new targeted therapeutic approaches for ovarian cancer.

Vascular endothelial growth factor C mRNA expression is a prognostic factor in epithelial ovarian cancer as detected by kinetic RT-PCR in formalin-fixed paraffin-embedded tissue.

Vascular endothelial growth factor C (VEGF-C) is a well described chemotactic and growth factor for lymphatic endothelial cells. Its inhibition leads to suppression of lymphatic and distant metastases in mouse models. In ovarian cancer, the relationship between VEGF-C expression and tumor behavior has not yet been determined by a quantitative method in vivo. Therefore, we used a new technique of RNA extraction from formalin-fixed paraffin-embedded tissue samples and determined the expression levels of VEGF-C mRNA in a study group of 97 ovarian cancer patients. Expression levels were correlated with clinicopathological features and patient survival. High VEGF-C expression was associated with worse overall (p = 0.0393) and progression-free (p = 0.0155) patient survival. In the subgroups of serous tumors and high-grade tumors, VEGF-C mRNA was still a negative indicator for patient survival (p = 0.0190 and 0.0311, respectively). A trend was observed among patients with high clinical stage (p = 0.0634). In multivariate survival analysis VEGF-C mRNA retained its prognostic influence on progression-free survival (p = 0.006, HR = 0.319 with a 95% confidence interval of 0.142-0.720). High VEGF-C expression was further associated with an increased residual tumor mass after primary cytoreductive surgery. We found no correlation of VEGF-C expression with tumor grade, FIGO stage, lymph node, or distant metastases. Our study demonstrates that high VEGF-C expression is associated with aggressive tumor behavior in ovarian cancer. mRNA extracted from paraffin-embedded tumor samples is suitable for VEGF-C gene expression studies.

Estrogen receptor 1 mRNA is a prognostic factor in ovarian carcinoma: determination by kinetic PCR in formalin-fixed paraffin-embedded tissue.

Epidemiological and cell culture studies indicate that ovarian carcinoma growth is dependent on estrogen stimulation. However, possibly due to the lack of a reliable biomarker that helps to select patients according to prognostically relevant estrogen receptor (ER) levels, clinical trials using anti-estrogenic therapeutics in ovarian carcinoma have had inconsistent results. Therefore, we tested if ER expression analysis by a quantitative method might be useful in this regard in formalin-fixed paraffin-embedded (FFPE) tissue. In a study group of 114 primary ovarian carcinomas expression of estrogen receptor 1 (ESR1) mRNA was analyzed using a new method for RNA extraction from FFPE tissue that is based on magnetic beads, followed by kinetic PCR. The prognostic impact of ESR1 mRNA expression was investigated and compared to ERalpha protein expression as determined by immunohistochemistry. In univariate survival analysis the expression level of ESR1 mRNA was a significant positive prognostic factor for patient survival (hazard ratio (HR) 0.230 (confidence interval (CI) 0.102-0.516), P=0.002). ERalpha protein expression was correlated to ESR1 mRNA expression (P=0.0001); however, ERalpha protein expression did not provide statistically significant prognostic information. In multivariate analysis, ESR1 mRNA expression emerged as a prognostic factor, independent of stage, grade, residual tumor mass, age, and ERalpha protein expression (HR 0.227 (CI 0.078-0.656), P=0.006). Our results indicate that the determination of ESR1 levels by kinetic PCR may be superior to immunohistochemical methods in assessment of biologically relevant levels of ER expression in ovarian carcinoma, and is feasible in routinely used FFPE tissue.

IMP3 expression in human ovarian cancer is associated with improved survival.

The insulin-like growth factor-II mRNA-binding protein IMP3 plays an important role in embryogenesis and recent reports suggest an involvement in tumorigenesis. Although IMP3 expression has been well studied in mouse and human fetal and adult gonads, its role in ovarian cancer is unknown. We investigated the expression of IMP3 at protein and mRNA levels in a cohort of primary ovarian carcinomas and in 11 ovarian cancer cell lines. Western blot analysis revealed an expression of IMP3 in all ovarian cancer cell lines and immunohistochemistry demonstrated a positive cytoplasmic staining in 32 of 68 carcinomas (47%). In contrast, epithelium of borderline tumors, as well as, benign ovarian lesions and normal ovaries exhibited only weak or no IMP3 expression. In univariate Kaplan-Meier analysis, IMP3 protein expression was significantly associated with better overall survival (P=0.048). To confirm these findings, we further determined IMP3 mRNA expression in 43 ovarian cancer specimens by real time quantitative reverse transcription-polymerase chain reaction. A significant correlation between protein and mRNA levels (r=0.414, P=0.006), as well as a correlation of IMP3 mRNA expression with patient overall survival (P=0.044), was observed. Our results demonstrate that IMP3 is expressed in a subpopulation of ovarian cancer and a marker of good prognosis.

Expression of multidrug resistance-associated protein 1 in invasive ovarian carcinoma: implication for prognosis.

AIMS: Multidrug resistance is a major impediment in chemotherapeutic treatment of ovarian carcinoma patients. The aim of this study was to investigate the expression of multidrug resistance-associated protein 1 (MRP1) and to assess the possible associations with clinicopathological variables and patient outcome in primary ovarian carcinoma. METHODS AND RESULTS: Tumour specimens from 129 patients were obtained before chemotherapy and analysed by immunohistochemistry on tissue microarrays, and by real-time reverse transcriptase-polymerase chain reaction on RNA extracted from formalin-fixed paraffin-embedded tissue specimens using a new technique. Significantly increased MRP1 protein expression was observed in high-grade tumours (P = 0.005) and advanced International Federation of Gynaecology and Obstetrics stages (P = 0.036). On univariate Kaplan-Meier analysis, patients with higher expression of MRP1 protein had significantly decreased overall survival (P = 0.006). On multivariate Cox regression analysis, MRP1 protein expression retained its significance as an independent negative prognostic marker for overall survival (hazard ratio = 6.52, P = 0.003). Furthermore, MRP1 expression correlated with topoisomerase IIalpha expression both at mRNA and protein level (P < 0.001 and P = 0.023, respectively). CONCLUSION: In summary, in patients with primary ovarian cancer, overexpression of MRP1 is an adverse marker for patient outcome and cancer aggressiveness. Our data provide a translational basis for further clinical studies on the predictive value of MRP1 expression for response to chemotherapy.

Topoisomerase IIalpha mRNA and protein expression in ovarian carcinoma: correlation with clinicopathological factors and prognosis.

Topoisomerase IIalpha (Top IIalpha) is a nuclear enzyme that plays a central role in DNA metabolism, and is a molecular target for a variety of chemotherapeutic agents. Top IIalpha has recently gained attention as a biomarker for therapy response and patient survival. In this study, we attempted to assess the feasibility of measuring Top IIalpha gene expression in RNA, isolated from archival formalin-fixed paraffin-embedded tissue specimens, which are used routinely in pathology laboratories. We have employed a new technique on the basis of magnetic particles' separation and purification of nucleic acids, and evaluated both protein and mRNA expressions from the same routinely processed tissue blocks. We investigated the expression of Top IIalpha mRNA and protein by real-time reverse transcription polymerase chain reaction and immunohistochemistry, in a cohort of 133 primary ovarian carcinomas, and evaluated the association between Top IIalpha expression and clincopathological variables as well as patient outcome. Elevated Top IIalpha mRNA expression was observed in high-grade tumors (P=0.003) and advanced stage disease (P=0.011). In univariate Kaplan-Meier analysis, patients with higher expression of Top IIalpha nuclear protein had a significantly decreased overall survival (P=0.045). Interestingly, we detected cytoplasmic protein expression of Top IIalpha in a subset of samples. Cytoplasmic expression of Top IIalpha was associated with the expression of chromosomal region maintenance/exportin 1 (CRM1)-a nuclear export protein (P=0.008). Our study suggests that Top IIalpha overexpression is involved in the progression of ovarian cancer in a subset of the patients. Our results encourage the further evaluation of the prognostic and predictive values of Top IIalpha expression in ovarian carcinoma, which might help to assess the patients' risk profile, and the planning of an individualized therapy.

Phospho-mTOR and phospho-4EBP1 in endometrial adenocarcinoma: association with stage and grade in vivo and link with response to rapamycin treatment in vitro.

PURPOSE: Endometrial adenocarcinoma, due to a frequent activation of PI3 K/AKT has been proposed as a candidate neoplasm for the treatment with mTOR inhibitors. Yet, data on the expression of mTOR cascade components in endometrial cancer are lacking. METHODS: To provide a basis for futher studies with mTOR inhibitors, we used immunohistochemistry to evaluate the expression of activated mTOR pathway components in 57 endometrial cancer surgical specimens in vivo, and investigated in vitro the relation between the activation of AKT/mTOR and the response to rapamycin. RESULTS: p-mTOR expression was associated with nuclear p-4EBP1 expression (P = 0.02), and was more frequent in tumors extending ouside the uterine corpus (P = 0.011). Nuclear p-4EBP1 expression was increased in carcinomas of poor differentiation (P = 0.012). In cultivated PTEN-deficient Ishikawa cells, in addition to an activation of AKT, a phosphorylation of mTOR and 4EBP1 was evident, while PTEN-wild type HEC-1A cells lacked AKT activation but revealed a reduced expression of p-mTOR and p-4EBP1. Rapamycin induced a growth reduction, which was clearly more pronounced in Ishikawa cells than in HEC-1A cells (P < 0.03) and could be observed for up to 6 days. CONCLUSISONS: Expression of mTOR and 4EBP1 characterize high-grade, high-stage endometrial adenocarcinomas and might be predictive markers of a response to rapamycin. Based on our results, we suggest that the expression of elements of the mTOR pathway in human tumor tissue should be further evaluated as a possible predictive marker in large-scale clinical studies as well as translational research protocols in clinical studies with mTOR inhibitors.