Acid ceramidase (AC)--a key enzyme of sphingolipid metabolism--correlates with better prognosis in epithelial ovarian cancer.

Acid ceramidase (AC), a key enzyme of sphingolipid metabolism, seems to play an important role in cancer progression. The objective of this study was to explore the expression of AC in ovarian cancer and its impact on prognosis. Expression analysis of AC in n=112 ovarian cancer patients was performed by immunohistochemical analysis of primary paraffin-embedded tumor samples. The results were scored on the basis of the staining intensity and percentage of positive tumor cells, resulting in an immunoreactive score from 0 to 12. These results were correlated to clinical and pathologic characteristics and survival. AC expression correlated significantly only with FIGO stage (0.047). In serous carcinoma, low level of AC was independently associated with reduced progression-free survival and overall survival of 12.0 mo [95% confidence interval (CI), 5.78-18.23] versus 18.1 mo (95% CI, 11.61-24.59; P=0.008) and 35.7 mo (95% CI, 22.24-47.16) versus 58.7 mo (95% CI, 36.48-80.91; P=0.032), respectively. In multivariate analysis, AC presents as an independent prognostic factor for progression-free survival (hazard ratio 1.88; 95% CI, 1.13-3.11; P=0.015). AC is a prognostic factor in epithelial ovarian cancer. Low AC expression can be associated with tumor progression in carcinoma of the ovaries. These results are in contrast to the concept of AC as a promoter for cancer progression. Nevertheless, they are supported by the lately discovered tumor-suppressing function of sphingosine, the enzymatic product of AC.

Gene expression profiling of luminal B breast cancers reveals NHERF1 as a new marker of endocrine resistance.

The luminal B subtype represents a group of high proliferating estrogen receptor positive breast cancers which are associated with a poor prognosis. Genes exclusively expressed in this subtype should help to better understand these tumors. In a finding cohort of 171 breast cancers luminal B specific genes were identified displaying strong expression in highly proliferating Ki-67 positive/ER positive tumors but no expression either in Ki-67 negative/ER positive or in Ki-67 positive/ER negative samples. The clinical relevance of the scaffold protein NHERF1 identified by this strategy was assessed in a total of 3,030 breast cancers. NHERF1 expression was associated with the luminal B subtype both in the finding and validation cohort. A positive correlation of NHERF1 expression with tumor size (P < 0.001), grade (P < 0.001), and HER2 status (P = 0.033) was observed. NHERF1 expression was associated with a worse survival in ER positive breast cancer (P < 0.001) and retained its prognostic value in multivariate analysis. For ER positive samples with low NHERF1 expression a benefit of endocrine therapy was detected (P = 0.007). In contrast no differences in disease free survival were found for high NHERF1 expressing breast cancers which were either treated with endocrine therapy or no systemic therapy. Our data indicate that NHERF1 expressing breast cancers seem to have a greater risk to develop resistance to endocrine therapy. However, based on previous findings of NHERF1 functioning in PI3K signalling from basic research, these tumors might be appropriate candidates for a targeted therapy of the PI3K/Akt pathway.

Data-driven derivation of cutoffs from a pool of 3,030 Affymetrix arrays to stratify distinct clinical types of breast cancer.

Pooling of microarray datasets seems to be a reasonable approach to increase sample size when a heterogeneous disease like breast cancer is concerned. Different methods for the adaption of datasets have been used in the literature. We have analyzed influences of these strategies using a pool of 3,030 Affymetrix U133A microarrays from breast cancer samples. We present data on the resulting concordance with biochemical assays of well known parameters and highlight critical pitfalls. We further propose a method for the inference of cutoff values directly from the data without prior knowledge of the true result. The cutoffs derived by this method displayed high specificity and sensitivity. Markers with a bimodal distribution like ER, PgR, and HER2 discriminate different biological subtypes of disease with distinct clinical courses. In contrast, markers displaying a continuous distribution like proliferation markers as Ki67 rather describe the composition of the mixture of cells in the tumor.

Prognostic relevance of glucosylceramide synthase (GCS) expression in breast cancer.

PURPOSE: Multidrug resistance (MDR) has been linked to sphingolipid metabolism and preclinical data ascribe glucosylceramide synthase (GCS) a major role for MDR especially in breast cancer cells but no profound data are available on the expression of this potential therapeutic target in clinical breast cancer specimens. METHODS: We analyzed microarray data of GCS expression in a large cohort of 1,681 breast tumors. RESULTS: Expression of GCS was associated with a positive estrogen receptor (ER) status, lower histological grading, low Ki67 levels and ErbB2 negativity (P < 0.001 for all). In univariate analysis there was a benefit for disease free survival for patients with tumors displaying low levels of GCS expression but this significance was lost in multivariate Cox regression. CONCLUSIONS: Our results suggest ER positive tumors may be the most promising candidates for a potential therapeutic application of GCS inhibitors.

Targeting cyclin B1 inhibits proliferation and sensitizes breast cancer cells to taxol.

BACKGROUND: Cyclin B1, the regulatory subunit of cyclin-dependent kinase 1 (Cdk1), is essential for the transition from G2 phase to mitosis. Cyclin B1 is very often found to be overexpressed in primary breast and cervical cancer cells as well as in cancer cell lines. Its expression is correlated with the malignancy of gynecological cancers. METHODS: In order to explore cyclin B1 as a potential target for gynecological cancer therapy, we studied the effect of small interfering RNA (siRNA) on different gynecological cancer cell lines by monitoring their proliferation rate, cell cycle profile, protein expression and activity, apoptosis induction and colony formation. Tumor formation in vivo was examined using mouse xenograft models. RESULTS: Downregulation of cyclin B1 inhibited proliferation of several breast and cervical cancer cell lines including MCF-7, BT-474, SK-BR-3, MDA-MB-231 and HeLa. After combining cyclin B1 siRNA with taxol, we observed an increased apoptotic rate accompanied by an enhanced antiproliferative effect in breast cancer cells. Furthermore, control HeLa cells were progressively growing, whereas the tumor growth of HeLa cells pre-treated with cyclin B1 siRNA was strongly inhibited in nude mice, indicating that cyclin B1 is indispensable for tumor growth in vivo. CONCLUSION: Our data support the notion of cyclin B1 being essential for survival and proliferation of gynecological cancer cells. Concordantly, knockdown of cyclin B1 inhibits proliferation in vitro as well as in vivo. Moreover, targeting cyclin B1 sensitizes breast cancer cells to taxol, suggesting that specific cyclin B1 targeting is an attractive strategy for the combination with conventionally used agents in gynecological cancer therapy.

Distant metastasis detected by routine staging in breast cancer patients participating in the national German screening programme: consequences for clinical practice.

PURPOSE: To determine frequency of routine radiological staging of breast cancer patients diagnosed in a German Breast Cancer Screening Center from 2007 to 2014, the incidence and consequences of distant metastases detected and the resulting implications for clinical routine. METHODS: Records of 896 patients with primary breast cancer diagnosed in the Screening Centre and treated in five participating hospitals were analyzed retrospectively. Evaluation included frequency and type of staging procedures and results with respect to distant metastasis and their consequences on clinical management. RESULTS: 894/896 Patients (99.8 %) received staging for distant metastases by bone scintigraphy, chest X-ray and liver sonography and/or CT/MRT diagnostics. Distant metastasis was suggested In 6/894 patients but excluded in 3 by further diagnostics or clinical course. Thus, 3 (0.3 %) were clinically verified to have metastatic disease in bone (n = 2; both pT2) or in bone and lung (n = 1; cT4, cN3). CONCLUSION: Due to the low incidence of verified metastatic disease, the high false positive rate of staging procedures and the unfavorable cost/benefit ratio routine radiological staging should be completely omitted in asymptomatic breast cancer patients diagnosed in a breast cancer screening programme.

Melanoma antigen family A identified by the bimodality index defines a subset of triple negative breast cancers as candidates for immune response augmentation.

BACKGROUND: Molecular markers displaying bimodal expression distribution can reveal distinct disease subsets and may serve as prognostic or predictive markers or represent therapeutic targets. Oestrogen (ER) and human epidermal growth factor receptor 2 (HER2) receptors are strongly bimodally expressed genes in breast cancer. MATERIAL AND METHODS: We applied a novel method to identify bimodally expressed genes in 394 triple negative breast cancers (TNBC). We identified 133 bimodally expressed probe sets (128 unique genes), 69 of these correlated to previously reported metagenes that define molecular subtypes within TNBC including basal-like, molecular-apocrine, claudin-low and immune cell rich subgroups but 64 probe sets showed no correlation with these features. RESULTS: The single most prominent functional group among these uncorrelated genes was the X chromosome derived Cancer/Testis Antigens (CT-X) including melanoma antigen family A (MAGE-A) and Cancer/Testis Antigens (CTAG). High expression of CT-X genes correlated with worse survival in multivariate analysis (HR 2.02, 95% CI 1.27-3.20; P=0.003). The only other significant variable was lymph node status. The poor prognosis of patients with high MAGE-A expression was ameliorated by the concomitant high expression of immune cell metagenes (HR 1.87, 95% CI 0.96-3.64; P=0.060), whereas the same immune metagene had lesser prognostic value in TNBC with low MAGE-A expression. CONCLUSIONS: MAGE-A antigen defines a very aggressive subgroup of TNBC; particularly in the absence of immune infiltration in the tumour microenvironment. These observations suggest a therapeutic hypothesis; TNBC with MAGE-A expression may benefit the most from further augmentation of the immune response. Novel immune stimulatory drugs such as (anti-cytotoxic T-lymphocyte antigen-4 CTLA-4) directed therapies provide a realistic opportunity to directly test this hypothesis in the clinic.

Gene expression of ceramide kinase, galactosyl ceramide synthase and ganglioside GD3 synthase is associated with prognosis in breast cancer.

PURPOSE: Sphingolipids are bioactive lipids implicated in apoptosis, cell survival and proliferation. We analyzed the prognostic value of enzymes from sphingolipid metabolism in breast cancer. METHODS: Differences in expression of ceramide galactosyl transferase (UGT8), ceramide kinase (CERK), and Ganglioside GD3-Synthase (ST8SIA1) in breast cancer cells were investigated by using microarray data of 1,581 tumor samples. RESULTS: UGT8, CERK, and ST8SIA1 were associated with poor pathohistological grading (P < 0.001). High CERK expression was correlated with ErbB2 status (P = 0.006). Among ER positive breast cancers a significant worse prognosis for patients with tumors showing low ST8SIA1 and UGT8 expression was observed. In the ER negative subgroup those samples with high CERK expression displayed a worse prognosis. In a multivariate analysis only ST8SIA1 and tumor size remained significant. CONCLUSIONS: Our experiments reveal that expression of enzymes from the sphingolipid metabolism has prognostic implications in breast cancer.

Loss of Plexin B1 is highly prognostic in low proliferating ER positive breast cancers--results of a large scale microarray analysis.

Plexins, cell-surface receptors for semaphorins, are involved in cell adhesion and migration. In the previous work, we demonstrated that the loss of Plexin B1 expression is associated with poor outcome in breast cancer patients. The goal of the present study was a validation of Plexin B1 expression in a large scale microarray dataset from n=1086 breast cancer patients. Plexin B1 correlates with ER status (p<0.001) and is of prognostic significance only in ER positive (p=0.024) but not in ER negative samples (p=0.85). Among ER positive tumours, the loss of Plexin B1 expression is associated with a positive ErbB2 status (p=0.05) and a high Ki67 expression (p=0.016) in univariate analysis. Multivariate Cox regression including all standard parameters among ER positive tumours revealed that Plexin B1 (HR 1.59, 95% confidence interval (CI) 1.03-2.47, p=0.036) remains a significant prognostic marker besides tumour size (HR 2.27, 95% CI 1.33-3.89, p=0.0028) and Ki67 (HR 1.78, 95% CI 1.12-2.84, p=0.0149). Interestingly, the prognostic value of Plexin B1 was pronounced in low proliferating ER positive tumours otherwise characterised by a low risk of recurrence. In conclusion, this study confirms our previous observations suggesting Plexin B1 as a new prognostic marker in ER positive breast cancers.