Cyclin E Expression and Prognosis in Breast Cancer Patients: A Meta-Analysis of Published Studies

Understanding Retinoblastoma Post-Translational Regulation for the Design of Targeted Cancer Therapies

Simple Summary

Rb1 is a regulator of cell cycle progression and genomic stability. This review focuses on post-translational modifications, their effect on Rb1 interactors, and their role in intracellular signaling in the context of cancer development. Finally, we highlight potential approaches to harness these post-translational modifications to design novel effective anticancer therapies.

Abstract

The retinoblastoma protein (Rb1) is a prototypical tumor suppressor protein whose role was described more than 40 years ago. Together with p107 (also known as RBL1) and p130 (also known as RBL2), the Rb1 belongs to a family of structurally and functionally similar proteins that inhibits cell cycle progression. Given the central role of Rb1 in regulating proliferation, its expression or function is altered in most types of cancer. One of the mechanisms underlying Rb-mediated cell cycle inhibition is the binding and repression of E2F transcription factors, and these processes are dependent on Rb1 phosphorylation status. However, recent work shows that Rb1 is a convergent point of many pathways and thus the regulation of its function through post-translational modifications is more complex than initially expected. Moreover, depending on the context, downstream signaling can be both E2F-dependent and -independent. This review seeks to summarize the most recent research on Rb1 function and regulation and discuss potential avenues for the design of novel cancer therapies.

Overexpression of VEGF-C correlates with a poor prognosis in esophageal cancer patients

BACKGROUND

The prognostic value of vascular endothelial growth factor C (VEGF-C) in patients with esophageal cancer (EC) remains controversial. The aim of this meta-analysis was to clarify the association of VEGF-C with survival in EC patients.

METHODS

We performed a meta-analysis that included eligible studies to expound the effect of VEGF-C in EC survival. Eligible studies published until November 2015 was identified using available databases. STATA 12.0 was performed in this meta-analysis.

RESULTS

We identified 13 studies, including 1203 patients, in this meta-analysis. The combined hazard ratio of 1.70 (95% CI, 1.43-2.03, P < 0.001) shows that VEGF-C overexpression was significantly correlated with poor overall survival in EC patients. Furthermore, the results suggested a significant relationship between VEGF-C expression and overall survival was also showed in studies with patient source, patient number ≥ 70, methods detecting VEGF-C by reverse transcription PCR (RT-PCR) or ELISA and histology type. Moreover, combined odds ratio of VEGF-C displayed that VEGF-C overexpression was significantly association with stage, depth of tumor invasion, lymph node status and metastasis of EC (P < 0.05). However, it has no correlation with differentiation degree of EC (P > 0.05).

CONCLUSION

VEGF-C overexpression shows an unfavorable prognosis for EC patients.

Cytoplasmic Cyclin E Predicts Recurrence in Patients with Breast Cancer

Purpose: Low molecular weight cyclin E (LMW-E) detected by Western blot analysis predicts for reduced breast cancer survival; however, it is impractical for clinical use. LMW-E lacks a nuclear localization signal that leads to accumulation in the cytoplasm that can be detected by IHC. We tested the hypothesis that cytoplasmic staining of cyclin E can be used as a predictor of poor outcome in different subtypes of breast cancer using patient cohorts with distinct clinical and pathologic features.Experimental Design: We evaluated the subcellular localization of cyclin E in breast cancer specimens from 2,494 patients from 4 different cohorts: 303 from a prospective study and 2,191 from retrospective cohorts [NCI, MD Anderson Cancer Center (MDA), and the United Kingdom (UK)]. Median follow-up times were 8.0, 10.1, 13.5, and 5.7 years, respectively.Results: Subcellular localization of cyclin E on IHC was associated with full-length (nuclear) and low molecular weight isoforms (cytoplasmic) of cyclin E on Western blot analysis. In multivariable analysis, cytoplasmic cyclin E staining was associated with the greatest risk of recurrence compared with other prognostic factors across all subtypes in three (NCI, MDA, and UK) of the cohorts. In the MDA cohort, cytoplasmic cyclin E staining outperformed Ki67 and all other variables as prognostic factors.Conclusions: Cytoplasmic cyclin E identifies patients with the highest likelihood of recurrence consistently across different patient cohorts and subtypes. These patients may benefit from alternative therapies targeting the oncogenic isoforms of cyclin E. Clin Cancer Res; 23(12); 2991-3002. ©2016 AACR.

Novel Molecular Markers for Breast Cancer

The use of molecular biomarkers assures that breast cancer (BC) patients receive optimal treatment. Established biomarkers, such as estrogen receptor, progesterone receptor, HER2, and Ki67, have been playing significant roles in the subcategorization of BC to predict the prognosis and decide the specific therapy to each patient. Antihormonal therapy using 4-hydroxytamoxifen or aromatase inhibitors have been employed in patients whose tumor cells express hormone receptors, while monoclonal antibody to HER2 has been administered to HER2-positive BCs. Although new therapeutic agents have been developed in the past few decades, many patients still die of the disease due to relapse; thus, novel molecular markers that predict therapeutic failure and those that can be targets for specific therapy are expected. We have chosen four of such molecules by reviewing recent publications, which are cyclin E, B-Myb, Twist, and DMP1β. The oncogenicity of these molecules has been demonstrated in vivo and/or in vitro through studies using transgenic mice or siRNAs, and their expressions have been shown to be associated with shortened overall or disease-free survival of BC patients. The former three molecules have been shown to accelerate epithelial-mesenchymal transition that is often associated with cancer stem cell-ness and metastasis; all these four can be novel therapeutic targets as well. Thus, large prospective studies employing immunohistochemistry will be needed to establish the predictive values of these molecules in patients with BC.

Cyclin E amplification, over-expression, and relapse-free survival in HER-2-positive primary breast cancer

Cyclin E is a well-characterized cell cycle regulator and an amplified oncogene in breast cancer. Over-expression of cyclin E has generally been associated with poor survival. Recent studies have shown an interaction between HER-2 (ERBB2) and cyclin E, but the exact mechanism is unknown. Interestingly, cyclin E over-expression has been associated with trastuzumab resistance. We studied cyclin E over-expression, CCNE1 amplification, and relapse-free survival in HER-2-positive primary breast cancers treated with and without trastuzumab therapy. Formalin-fixed paraffin-embedded tissue samples from 202 HER-2-positive breast carcinomas were studied. Expression levels of cyclin E and proliferation marker Ki-67 were determined using immunohistochemistry. Chromogenic in situ hybridization (CISH) with a gene-specific bacterial artificial chromosome (BAC) probe was used to analyze presence of CCNE1 amplification. Majority of HER-2-positive breast carcinomas exhibited nuclear staining for cyclin E protein. Cyclin E was highly expressed (≥50 % cells) in 37 % of cases. Incidence of CCNE1 amplification (≥6 gene copies/cell or clusters) was 8 %. Cyclin E amplification and over-expression were strongly associated with each other, grade, hormone receptors, and Ki-67. Neither high cyclin E expression nor CCNE1 amplification was associated with relapse-free survival (RFS) irrespective of short-term (9-week regimen) adjuvant trastuzumab therapy. These results confirm cyclin E and HER-2 gene co-amplification in a fraction of HER-2-positive breast cancers. Cyclin E is frequently over-expressed but appears to have limited value as a prognostic or predictive factor in HER-2-positive breast cancer regardless of trastuzumab therapy.

Survivin over-expression is correlated with a poor prognosis in esophageal cancer patients

BACKGROUND

The prognostic role of survivin in esophageal cancer (EC) remains controversial. This meta-analysis aimed to clarify the association of survivin with survival in EC patients.

METHODS

Relevant studies published up to November 2014 were identified using PubMed and Embase. Only studies in which survivin was detected through immunohistochemical staining were included. STATA 12.0 was used in this meta-analysis.

RESULTS

A total of 9 studies, which comprised 610 patients, were included in the meta-analysis. The combined hazard ratio (HR) of 1.76 (95% CI, 1.40-2.21; P<0.001) suggests that survivin overexpression in EC patients was significantly associated with poor overall survival. Moreover, the results showed a significant relationship between overall survival and survivin expression was also displayed in studies with a non-Asian country (HR, 1.75; 95% CI, 1.30-2.35), patient number ≥ 50 (HR, 1.86; 95% CI, 1.57-2.20), the cut-off level ≥ 5% (HR, 1.43; 95% CI, 0.94-2.17) and the esophageal squamous cell carcinoma (HR, 1.82; 95% CI, 1.43-2.30). However, combined odds ratio of survivin indicated that survivin overexpression has no correlation with stage, grade of differentiation, lymph node status, depth of invasion and distant metastasis of EC (P>0.05).

CONCLUSION

Survivin overexpression is associated with poor prognosis in EC patients.

Cyclin E1 is a strong prognostic marker for death from lymph node negative breast cancer. A population-based case-control study

BACKGROUND

A large proportion of women with lymph node negative breast cancer treated with systemic adjuvant treatment do not benefit from such therapy since the patient is already cured by local treatment. Several studies have suggested that proliferation markers are strong prognostic factors in early breast cancer. Cyclins are probably the most specific markers of cell proliferation. Previously high expression of cyclin E has been associated with breast cancer recurrence.

MATERIALS AND METHODS

In this study we investigate the prognostic value of cyclin E1 in node negative breast cancer patients. In a population-based cohort 186 women who died from breast cancer were defined as cases and 186 women alive at the corresponding time as controls. Inclusion criteria were tumour size ≤ 50 mm, no lymph node metastases and no adjuvant chemotherapy. The study was designed to detect an odds ratio of 2.5 with a power of 90% and significance level of 0.05. Cyclin E1 was determined with immunohistochemistry (IHC) on tissue microarray (TMA).

RESULTS

High expression of cyclin E1 was significantly associated with breast cancer death, in both uni- and multivariate analyses with odds ratios (OR) 2.3 [univariate, 95% confidence interval (CI) 1.5-3.6] and 2.1 (multivariate, 95% CI 1.2-3.5).

DISCUSSION

Cyclin E1 is a strong prognostic factor for breast cancer death in a population-based and node negative patient cohort and can identify high-risk patients in this group.

Prognostic Value of Expression of Cyclin E in Gastrointestinal Cancer: A Systematic Review and Meta-Analysis

Cyclin E is a critical regulator in cell cycle and promotes the initiation of DNA replication and centrosome duplication in late G1. The overexpression of cyclin E is common in cancers of the digestive system. However, whether cyclin E represents a prognostic biomarker in gastrointestinal cancer remains controversial. We reviewed the published literatures to clarify the association between cyclin E determined by immunohistochemistry (IHC) and survival in gastrointestinal cancer. Literatures were searched in PubMed and Cochrane Library published up to December 1, 2014. A total of 282 articles were initially identified, and 14 articles were included in this study. Meta-analysis was performed for 10 studies with a total of 1300 patients. Combined hazard risk (HR) and corresponding 95% confidence interval (CI) were calculated by random-effect model due to the heterogeneity. The quality of included studies was assessed by the Newcastle-Ottawa Scale and the Methodological Index for Non-Randomized Studies (MINORS). We found that high level of cyclin E was a predicator of poor prognosis among patients with gastrointestinal cancer (HR = 1.67, 95% CI = 1.06-2.63, P = .028). In summary, overexpression of cyclin E is associated with poor prognosis in gastrointestinal cancer and expression of cyclin E determined by IHC might be a prognostic marker for gastrointestinal cancer in clinical practice.

Sublobectomy versus lobectomy for stage IA (T1a) non-small-cell lung cancer: a meta-analysis study

Background

Although lobectomy is considered the standard surgical treatment for the majority of patients with non-small-cell lung cancer (NSCLC), the operation project for patients with stage IA NSCLC (T1a, tumor diameter ≤2 cm) remains controversial. Sublobectomy is appropriate only in certain patients as many doctors consider it to be overtreatment. We evaluated the five-year overall survival rate of sublobectomy and lobectomy for stage IA NSCLC (T1a, tumor diameter ≤2 cm) through a meta-analysis.

Methods

The five-year overall survival rate (OS) of stage IA (T1a) NSCLC after sublobectomy (including wedge resection and segmentectomy) and lobectomy were compared. We also compared the OS of stage IA (T1a) NSCLC after segmentectomy and lobectomy. The log (hazard ratio, ln (HR)) and its standard error (SE) were used as the outcome measure for data combining.

Results

There were 12 eligible studies published between 1994 and 2013 in which the total number of participants was 18,720. When compared to lobectomy, there was a statistically significant difference of sublobectomy on OS of stage IA (T1a) NSCLC patients (HR 1.38; 95% confidence interval (95% CI), 1.19 to 1.61; P <0.0001). For the comparison between segmentectomy and lobectomy, there was also a statistically significant difference of segmentectomy alone on OS of stage IA (T1a) NSCLC patients (HR 1.48; 95% CI: 1.27 to 1.73; P <0.00001)

Conclusions

We have concluded that in stage IA (T1a) patients sublobectomy, including segmentectomy and wedge resection, causes a lower survival rate than lobectomy.

CDK/CCN and CDKI alterations for cancer prognosis and therapeutic predictivity

The regulation of cell growth and division occurs in an accurate sequential manner. It is dictated by the accumulation of cyclins (CCNs) and cyclin-dependent kinases (CDKs) complexes and degradation of CCNs. In human tumors, instead, the cell cycle is deregulated, causing absence of differentiation and aberrant cell growth. Oncogenic alterations of CCNs, CDKs, and CDKIs have been reported in more than 90% of human cancers, and the most frequent are those related to the G1 phase. Several molecular mechanisms, including gene overexpression, chromosomal translocations, point mutations, insertions and deletions, missense and frame shift mutation, splicing, or methylation, may be responsible for these alterations. The cell cycle regulators are involved in tumor progression given their association with cancers characterized by higher incidence of relapses and chemotherapy resistance. In the last decade anticancer drug researches focused on new compounds, able to target molecules related to changes in genes associated with tumor status. Recently, the studies have focused on the restoration of cell cycle control modulating molecular targets involved in cancer-cell alterations. This paper aims to correlate alterations of cell cycle regulators with human cancers and therapeutic responsivity.

Survivin rs9904341 (G>C) polymorphism contributes to cancer risk: an updated meta-analysis of 26 studies

Survivin, a member of the inhibitor of apoptosis protein family, encoded by BIRC5, is involved in the regulation of apoptosis and in cell cycle control. Emerging evidences indicate that polymorphism in BIRC5 promoter (rs9904341) is associated with cancer risk, but the results of individually published studies are inconclusive. Thus, an updated meta-analysis was performed. PubMed was searched for all eligible studies. Pooled odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated to assess the association strength. Stratified analysis was performed by cancer type, source of control, genotyping method, and ethnicity. A number of 26 studies, including 6,041 cases and 7,567 controls were analyzed in this meta-analysis. Overall, significantly increased cancer risk was associated with survivin rs9904341 polymorphism when all studies were pooled (CC vs. GG: OR = 1.36, 95 % CI = 1.09-1.69; P heterogeneity < 0.001; CC vs GC/GG: OR = 1.32, 95 % CI = 1.11-1.57; P heterogeneity < 0.001). Stratified analysis by cancer type revealed that the survivin rs9904341 polymorphism may increase the risk of colorectal cancer, renal cell cancer, gastric cancer, and bladder cancer. Further subgroup analysis by ethnicity indicated that there was a statistically increased cancer risk in Asians but not Caucasians. In this updated meta-analysis of 26 studies, we conclude that the survivin rs9904341 polymorphism might contribute to risk of various cancers, especially in Asian populations.

New castanospermine glycoside analogues inhibit breast cancer cell proliferation and induce apoptosis without affecting normal cells

sp²-Iminosugar-type castanospermine analogues have been shown to exhibit anti-tumor activity. However, their effects on cell proliferation and apoptosis and the molecular mechanism at play are not fully understood. Here, we investigated the effect of two representatives, namely the pseudo-S- and C-octyl glycoside 2-oxa-3-oxocastanospermine derivatives SO-OCS and CO-OCS, on MCF-7 and MDA-MB-231 breast cancer and MCF-10A mammary normal cell lines. We found that SO-OCS and CO-OCS inhibited breast cancer cell viability in a concentration- and time-dependent manner. This effect is specific to breast cancer cells as both molecules had no impact on normal MCF-10A cell proliferation. Both drugs induced a cell cycle arrest. CO-OCS arrested cell cycle at G1 and G2/M in MCF-7 and MDA-MB-231cells respectively. In MCF-7 cells, the G1 arrest is associated with a reduction of CDK4 (cyclin-dependent kinase 4), cyclin D1 and cyclin E expression, pRb phosphorylation, and an overexpression of p21^Waf1/Cip1. In MDA-MB-231 cells, CO-OCS reduced CDK1 but not cyclin B1 expression. SO-OCS accumulated cells in G2/M in both cell lines and this blockade was accompanied by a decrease of CDK1, but not cyclin B1 expression. Furthermore, both drugs induced apoptosis as demonstrated by the increased percentage of annexin V positive cells and Bax/Bcl-2 ratio. Interestingly, in normal MCF-10A cells the two drugs failed to modify cell proliferation, cell cycle progression, cyclins, or CDKs expression. These results demonstrate that the effect of CO-OCS and SO-OCS is triggered by both cell cycle arrest and apoptosis, suggesting that these castanospermine analogues may constitute potential anti-cancer agents against breast cancer.

K(+) channels and cell cycle progression in tumor cells

K⁺ ions play a major role in many cellular processes. The deregulation of K⁺ signaling is associated with a variety of diseases such as hypertension, atherosclerosis, or diabetes. K⁺ ions are important for setting the membrane potential, the driving force for Ca²⁺ influx, and regulate volume of growing cells. Moreover, it is increasingly recognized that K⁺ channels control cell proliferation through a novel signaling mechanisms triggered and modulated independently of ion fluxes. In cancer, aberrant expression, regulation and/or sublocalization of K⁺ channels can alter the downstream signals that converge on the cell cycle machinery. Various K⁺ channels are involved in cell cycle progression and are needed only at particular stages of the cell cycle. Consistent with this idea, the expression of Eag1 and HERG channels fluctuate along the cell cycle. Despite of acquired knowledge, our understanding of K⁺ channels functioning in cancer cells requires further studies. These include identifying the molecular mechanisms controlling the cell cycle machinery. By understanding how K⁺ channels regulate cell cycle progression in cancer cells, we will gain insights into how cancer cells subvert the need for K⁺ signal and its downstream targets to proliferate.

Prognostic value of cyclin E expression in breast cancer: a meta-analysis

Cyclin E is an important regulator of cell cycle progression. Various studies examined the relationship between cyclin E overexpression with the clinical outcome in patients with breast cancer but yielded conflicting results. Electronic databases updated to May 2013 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between cyclin E overexpression and survival of patients with breast cancer. Survival data were aggregated and quantitatively analyzed. We conducted a final analysis of 7,759 patients from 23 eligible studies and evaluated the correlation between cyclin E overexpression and survival in patients with breast cancer. Combined hazard ratios suggested that cyclin E overexpression had an unfavorable impact on overall survival (OS) (hazard ratio (HR) = 1.30, 95% confidence interval (CI), 1.12-1.49) and breast cancer-specific survival (BCSS) (HR = 1.48, 95% CI, 1.03-1.93), but not disease-free survival (HR = 1.11; 95% CI, 0.96-1.27) in patients with breast cancer. Significantly, risks were found among stage I-II breast cancer for (HR = 1.75; 95% CI, 1.30-2.19). Cyclin E overexpression is associated with poor OS and BCSS in breast cancer.

Cytoplasmic HuR expression correlates with P-gp, HER-2 positivity, and poor outcome in breast cancer

HuR is an ubiquitously expressed RNA-binding protein that stabilizes messenger RNA and regulates translation. This protein has been shown to play an important role in carcinogenesis and cancer progression. P-glycoprotein (P-gp) is the product of the multidrug resistance 1 gene, and the overexpression of P-gp induces multidrug resistance and represents a major obstacle in cancer chemotherapy. The purpose of this study was to determine the expression of HuR and P-gp in human breast cancer tissues and analyze the relationship between HuR or P-gp expression and the clinical-pathological variables and patient outcomes. Immunohistochemistry was used to determine HuR and P-gp expression in 82 human breast cancer tissues and 20 matched adjacent noncancerous tissues. Additionally, 16 benign breast tumor samples were used as controls. The overexpression of cytoplasmic HuR was found in breast cancer but not in the matched adjacent noncancerous tissues or benign breast tumors. The expression levels of cytoplasmic HuR were significantly associated with increased age, high nuclear grade, and the positive expression of the ER, PR, and HER-2/neu. HuR was also associated with the expression of P-gp protein. Furthermore, univariate analysis indicates that patients with high expression levels of cytoplasmic HuR or P-gp had significantly reduced survival compared to patients with low expression levels. A multivariate analysis showed that age at diagnosis, nuclear grade, and cytoplasmic HuR positivity were independent indicators for disease-free survival and overall survival in patients with breast cancer. In conclusion, cytoplasmic HuR expression detected by immunohistochemical staining is a negative prognostic indicator for survival in patients with breast cancer.

Differences in degradation lead to asynchronous expression of cyclin E1 and cyclin E2 in cancer cells

Cyclin E1 is expressed at the G 1/S phase transition of the cell cycle to drive the initiation of DNA replication and is degraded during S/G2M. Deregulation of its periodic degradation is observed in cancer and is associated with increased proliferation and genomic instability. We identify that in cancer cells, unlike normal cells, the closely related protein cyclin E2 is expressed predominantly in S phase, concurrent with DNA replication. This occurs at least in part because the ubiquitin ligase component that is responsible for cyclin E1 downregulation in S phase, Fbw7, fails to effectively target cyclin E2 for proteosomal degradation. The distinct cell cycle expression of the two E-type cyclins in cancer cells has implications for their roles in genomic instability and proliferation and may explain their associations with different signatures of disease.

Lymphatic microvessel density and vascular endothelial growth factor-C and -D as prognostic factors in breast cancer: a systematic review and meta-analysis of the literature

The use of lymphatic microvessel density (LVD) and pro-lymphangiogenic mediators as prognostic factors for survival in breast cancer remains controversial. We searched the electronic databases PubMed and EMBASE without language restrictions for relevant literature to aggregate the survival results. To be eligible, every study had to include the assessment of the LVD or the expression of vascular endothelial growth factor (VEGF)-C or -D in patients with breast cancer and provide a survival comparison, including disease-free survival (DFS) or overall survival (OS), according to the LVD, VEGF-C or VEGF-D status. Across all studies, 56.64 % of patients were considered to have a VEGF-C-positive tumor, and 65.54 % of patients had VEGF-D-positive tumors. High LVD had an unfavorable impact on DFS, with a pooled hazard ratio (HR) of 2.222 (95 % CI 1.579-3.126) and an OS with a HR of 2.493 (95 % CI 1.183-5.25). According to the different lymphatic makers, the subgroup HR in the D2-40 studies was 2.431 (95 % CI 1.622-3.644) for DFS and 4.085 (95 % CI 1.896-8.799) for OS. VEGF-C overexpression, as assessed by immunochemistry, was a prognostic factor for decreased DFS (HR 2.164; 95 % CI 1.256-3.729) and for decreased OS (HR 2.613; 95 % CI 1.637-4.170). VEGF-D overexpression was a significant although weak prognostic factor for DFS only when assessed by immunochemistry, with a HR of 2.108 (95 % CI 1.014-4.384). Our meta-analysis demonstrated that LVD, VEGF-C and VEGF-D could predict poor prognosis in patients with breast cancer. However, standardization of the assessment of LVD and for the expression of lymphangiogenesis factors is needed.

Clinicopathological and prognostic significance of survivin over-expression in patients with esophageal squamous cell carcinoma: a meta-analysis

Background

The prognostic significance of survivin for survival of patients with esophageal squamous cell carcinoma (ESCC) remains controversial. Thus, meta-analysis of the literatures was performed in order to demonstrate its expression impact on ESCC clinicopathological features and prognosis.

Methodology

Relevant literatures were searched using PubMed, EMBASE and Medline Databases. Revman5.0 software was used to pool eligible studies and summary hazard ratio (HR). Correlation between survivin expression and clinicopathological features of ESCC was analyzed.

Principal Findings

Final analysis of 523 patients from 7 eligible studies was performed. Combined HR of survivin location in nuclei suggested that survivin expression has an unfavorable impact on ESCC patients' survival (n = 277 in 3 studies; HR = 1.89, 95% CI: 1.45–2.96; Z = 4.69; P<0.0001). Nevertheless, combined HR of survivin location in cytoplasm displayed that survivin expression has no significance for prognosis of ESCC patients (n = 113 in 2 studies; HR = 0.96, 95% CI: 0.96–5.69; Z = 0.04; P = 0.97); Combined odds ratio (OR) of survivin location in cytoplasm indicated that survivin expression is associated with ESCC advanced stage (n = 113 in 2 studies; OR = 0.36, 95% CI: 0.14–0.93; Z = 2.10; P = 0.04). Whereas, combined OR of survivin location in nuclei exhibited that survivin over-expression has no correlation with cell differentiation grade, lymph node status, depth of invasion, stage, and metastasis of ESCC.

Conclusions

This study showed that survivin expression detected by immunohistochemistry seems to be associated with a worse prognosis of ESCC patients. Survivin subcellular location may be an important factor impacting on ESCC development. Larger prospective studies should be performed to evaluate the status of survivin in predicting prognosis of patients with ESCC.

The role of cyclin D1 expression and patient's survival in non-small-cell lung cancer: a systematic review with meta-analysis

BACKGROUND

The role of cell-cycle protein cyclin D1 in lung cancer remains controversial. To clarify its impact on survival in non-small-cell lung cancer (NSCLC), we performed a meta-analysis on the currently available medial literature to quantitatively assess its role on survival of NSCLC according to cyclin D1 status.

METHOD

Published studies that investigated the association between cyclin D1 expression and NSCLC survival were identified. Meta-analysis was performed by using a DerSimonian-Laird model. Funnel plot was used to investigate publication bias and sources of heterogeneity were identified by using meta-regression analysis.

RESULT

A total of 24 studies with 2731 patients were evaluable for this meta-analysis. No statistical significance was found that cyclin D1 expression was associated with poor prognosis in NSCLC (hazard ratio 1.08 [95% CI, 0.80-1.45]) without publication bias found. But there was significant heterogeneity present; meta-regression analysis was used to explore the sources of heterogeneity and revealed that the outcome of analysis was influenced by cutoff values and ethnicity. No difference between positive and negative studies on study quality assessment was present.

CONCLUSION

The cyclin D1 expression is unlikely to be useful as a prognostic marker for NSCLC in clinical practice from current evidence. The conclusion should be confirmed by a large well-designed prospective study.

Individualization of treatment strategies

This section focuses on different aspects of the individualization of hormone treatment in breast cancer. This includes tumor-related biological factors such as expression of hormone receptors, HER-2, and Ki-67; host-related factors such as CYP2D6 or body mass index, and risk and/or development of specific toxicities and treatment adherence. The best predictor of response to hormonal interventions is the expression of hormone receptors, in particular, estrogen receptors. Treatment adherence and compliance are key factors and strategies aiming to identify and intervene when patients are at risk of abandoning treatment. Currently, routine assessment of CYP2D6 is not recommended to guide tamoxifen treatment. Likewise, there are no criteria regarding bone mass density, lipid profile, or arthralgias to recommend one class of agent versus another. Aromatase inhibitors should not be administered to patients who are pre- or perimenopausal.

Impact of cyclin E overexpression on Smad3 activity in breast cancer cell lines

Smad3, a component of the TGFβ signaling pathway, contributes to G1 arrest in breast cancer cells. Overexpression of the cell cycle mitogen, cyclin E, is associated with poor prognosis in breast cancer, and cyclin E/CDK2 mediated phosphorylation of Smad3 has been linked with inhibition of Smad3 activity. We hypothesized that the biological aggressiveness of cyclin E overexpressing breast cancer cells would be associated with CDK2 phosphorylation and inhibition of the tumor suppressant action of Smad3. Expression constructs containing empty vector, wild type (WT) Smad3, or Smad3 with CDK phosphorylation site mutations were co-transfected with a Smad3-responsive reporter construct into parental, vector control (A1), or cyclin E overexpressing (EL1) MCF7 cells. Smad3 function was evaluated by luciferase reporter assay and mRNA analysis. The impact of a Cdk2 inhibitor and cdk2 siRNA on Smad3 activity was also assessed. Cells expressing Smad3 containing mutations of the CDK phosphorylation sites had higher p15 and p21 and lower c-myc mRNA levels, as well as higher Smad3-responsive reporter activity, compared with controls or cells expressing WT Smad3. Transfection of cdk2 siRNA resulted in a significant increase in Smad3-responsive reporter activity compared with control siRNA; reporter activity was also increased after the treatment with a Cdk2 inhibitor. Thus, cyclin E-mediated inhibition of Smad3 is regulated by CDK2 phosphorylation of the Smad3 protein in MCF7 cells. Inhibition of CDK2 may lead to restoration of Smad3 tumor suppressor activity in breast cancer cells, and may represent a potential treatment approach for cyclin E overexpressing breast cancers.

Reduced expression of ubiquitin ligase FBXW7 mRNA is associated with poor prognosis in breast cancer patients

FBXW7 is a cell cycle regulatory gene that ubiquitinates positive cell cycle regulators such as c-Myc and cyclin E, allowing for cell cycle exit. Defects in the FBXW7 gene that lead to cell cycle re-entry and expedite the G1-S transition is thought to be one of the causes of cancer development. However, its clinical importance for breast cancer patients remains undetermined. This prompted us to investigate its expression level in breast cancer patients to establish its clinical significance. The expression level of FBXW7 mRNA was assessed in 186 cases of primary invasive breast cancer. Correlations between FBXW7 mRNA expression and clinicopathological factors, prognoses and immunohistochemical expression levels of Ki-67, FBXW7, c-Myc and cyclin E were analyzed. In vitro investigation of FBXW7 gene silencing in a breast cancer cell line was conducted. FBXW7 mRNA was expressed at significantly lower levels in patients with high histological grade and hormone receptor-negative tumors. Patients with lower FBXW7 mRNA expression had a poorer prognosis for breast cancer-specific survival than those with higher expression. A high Ki-67 labeling index and positive cyclin E protein expression were significantly correlated with lower FBXW7 mRNA expression. In vitro, silencing FBXW7 enhanced expression of c-Myc and cyclin E proteins and upregulated both cell proliferation and G1-S transition. In breast cancer, reduced FBXW7 mRNA expression may have independent prognostic potential through the enhanced function of cell cycle regulatory proteins.

Overexpression of POLQ confers a poor prognosis in early breast cancer patients

Depletion of POLQ (DNA polymerase theta) has recently been shown to render tumour cells more sensitive to radiotherapy whilst having little or no effect on normal tissues. This finding led us to investigate whether tumours that overexpress POLQ are associated with an adverse outcome. We therefore correlated the clinical outcomes of two retrospective series of patients with early breast cancer with the expression levels of POLQ, as determined by microarray gene expression analysis. We found that a significant number of tumours overexpressed POLQ and that overexpression was correlated with ER negative disease (p=0.047) and high tumour grade (p=0.004), both of which are associated with poor clinical outcomes. POLQ overexpression was associated with poor relapse free survival rates on both univariate (HR 5.80; 95% CI, 2.220 to 15.159; p<0.001) and multivariate analysis (HR 8.086; 95% CI 2.340 to 27.948 p=0.001). Analysis of other published clinical series confirmed that POLQ overexpression is associated with adverse clinical outcomes. The poor prognosis associated with POLQ is independent of other clinical or pathological features. The mechanism that causes this adverse outcome remains to be elucidated but may in part arise from resistance to adjuvant treatment. These findings, combined with the limited normal tissue expression of POLQ, make it a very appealing target for possible clinical exploitation.

Distinct and redundant functions of cyclin E1 and cyclin E2 in development and cancer

The highly conserved E-type cyclins are core components of the cell cycle machinery, facilitating the transition into S phase through activation of the cyclin dependent kinases, and assembly of pre-replication complexes on DNA. Cyclin E1 and cyclin E2 are assumed to be functionally redundant, as cyclin E1-/- E2-/- mice are embryonic lethal while cyclin E1-/- and E2-/- single knockout mice have primarily normal phenotypes. However more detailed studies of the functions and regulation of the E-cyclins have unveiled potential additional roles for these proteins, such as in endoreplication and meiosis, which are more closely associated with either cyclin E1 or cyclin E2. Moreover, expression of each E-cyclin can be independently regulated by distinct transcription factors and microRNAs, allowing for context-specific expression. Furthermore, cyclins E1 and E2 are frequently expressed independently of one another in human cancer, with unique associations to signatures of poor prognosis. These data imply an absence of co-regulation of cyclins E1 and E2 during tumorigenesis and possibly different contributions to cancer progression. This is supported by in vitro data identifying divergent regulation of the two genes, as well as potentially different roles in vivo.

Aberrant expression of cyclin E in low-risk node negative breast cancer

BACKGROUND

Cyclin E is a cell cycle regulatory protein which occurs in G1, peaks in late G1 and is degraded in early S-phase. Cyclin E overexpression appears to be an independent prognostic factor for overall survival in breast cancer. Nuclear cyclin A is a reliable marker for S-and G2-phases. Consequently, aberrant expression of cyclin E can be detected by simultaneous immunostainings for cyclin A and cyclin E. Studies have shown that aberrant cyclin E might provide additional prognostic information compared to that of cyclin E alone. This study aimed to investigate cyclin E and aberrant cyclin E expression in low-risk node negative breast cancer.

MATERIAL AND METHODS

We compared women that died from their breast cancer (n=17) with women free from relapse > 8 years after initial diagnosis (n=24). All women had stage I, low risk breast cancer. The groups were matched regarding tumour size, receptor status, adjuvant chemotherapy and tumour differentiation. Tumour samples were analysed regarding expression of cyclin A, cyclin E and double-stained tumour cells using immunoflourescence staining and digital microscopy.

RESULTS

No differences were seen regarding expression of cyclin E or aberrant cyclin E in cases compared to controls.

DISCUSSION

We conclude that neither cyclin E nor aberrant cyclin E is a prognostic factor in low-risk node negative breast cancer patients.

Adjuvant chemotherapy in oesophageal cancer: a meta-analysis and experience from the Shanghai Cancer Hospital

Whether adjuvant chemotherapy increases survival of oesophageal cancer patients has been widely debated. The present study used meta-analysis software to combine data from six studies up to July 2007 that were found and selected as suitable, comprising a total of 1001 oesophageal cancer patients. The results indicated that adjuvant chemotherapy did not significantly improve outcome in oesophageal cancer patients. A trend towards improved outcome from adjuvant chemotherapy was found in lymph node-positive patients, but did not reach significance. In our own study including 270 oesophageal cancer patients, adjuvant chemotherapy did not improve overall patient survival, but did improve survival for patients with metastases in cervical and/or celiac lymph nodes (stage IVa). Although our study had the largest patient sample, more prospective clinical trials with large numbers of patients are necessary to confirm the value of adjuvant chemotherapy in stage IVa patients.

Effects of common germline genetic variation in cell cycle control genes on breast cancer survival: results from a population-based cohort

INTRODUCTION

Somatic alterations have been shown to correlate with breast cancer prognosis and survival, but less is known about the effects of common inherited genetic variation. Of particular interest are genes involved in cell cycle pathways, which regulate cell division.

METHODS

We examined associations between common germline genetic variation in 13 genes involved in cell cycle control (CCND1, CCND2, CCND3, CCNE1, CDK2 [p33], CDK4, CDK6, CDKN1A [p21, Cip1], CDKN1B [p27, Kip1], CDKN2A [p16], CDKN2B [p15], CDKN2C [p18], and CDKN2D [p19]) and survival among women diagnosed with invasive breast cancer participating in the SEARCH (Studies of Epidemiology and Risk factors in Cancer Heredity) breast cancer study. DNA from up to 4,470 women was genotyped for 85 polymorphisms that tag the known common polymorphisms (minor allele frequency > 0.05) in the genes. The genotypes of each polymorphism were tested for association with survival using Cox regression analysis.

RESULTS

The rare allele of the tagging single nucleotide polymorphism (SNP) rs2479717 is associated with an increased risk of death (hazard ratio = 1.26 per rare allele carried, 95% confidence interval: 1.12 to 1.42; P = 0.0001), which was not attenuated after adjusting for tumour stage, grade, and treatment. This SNP is part of a large linkage disequilibrium block, which contains CCND3, BYSL, TRFP, USP49, C6ofr49, FRS3, and PGC. We evaluated the association of survival and somatic expression of these genes in breast tumours using expression microarray data from seven published datasets. Elevated expression of the C6orf49 transcript was associated with breast cancer survival, adding biological interest to the finding.

CONCLUSION

It is possible that CCND3 rs2479717, or another variant it tags, is associated with prognosis after a diagnosis of breast cancer. Further study is required to validate this finding.

Tissue microarrays in clinical oncology

Tissue microarray (TMA) is a recently implemented, high-throughput technology for the analysis of molecular markers in oncology. This research tool permits the rapid assessment of a biomarker in thousands of tumor samples, using commonly available laboratory assays such as immunohistochemistry and in situ hybridization. Although introduced less than a decade ago, TMA has proven to be invaluable in the study of tumor biology, the development of diagnostic tests, and the investigation of oncologic biomarkers. This review describes the impact of TMA-based research in clinical oncology and its potential future applications. Technical aspects of TMA construction and the advantages and disadvantages inherent to this technology are also discussed.

The role of survivin on overall survival of non-small cell lung cancer, a meta-analysis of published literatures

The prognostic value of survivin for survival of patients with non-small cell lung cancer (NSCLC) remains controversial. The authors performed a meta-analysis of the literatures in order to clarify its impact. Published studies were identified using an electronic search in order to aggregate the available survival results. To be eligible, a study had to have dealt with survivin assessment in NSCLC patients on the primary site and have analyzed survival according to survivin expression. There were 10 eligible studies and data from eight studies where non-location specific immunohistochemistry (IHC) definition system, in situ hybridization (ISH) and RT-PCR used were combined to present the impact of survivin on overall survival (OS) of NSCLC. The level of survivin expression correlated with the OS of NSCLC patients significant (RR 1.88, 95% CI 1.31-2.70, P=0.0006). Data of seven studies were combined to demonstrate that the level of survivin correlated with the OS of NSCLC patients who had received radical surgeries (RR 1.79, 95% CI 1.45-2.20, P<0.00001). Data from three studies were combined to find that the level of nuclear survivin did not have impact on OS of NSCLC patients (RR 1.58, 95% CI 0.87-2.85, P=0.13). Positive-survivin expression might be a prognostic factor for NSCLC patients, nuclear survivin positivity could not work as a prognostic factor for NSCLC patients based on current clinical data. Larger clinical trails with widely accepted assessment methods are necessary to define the precise prognostic significance for survivin in NSCLC patients.

Cell cycle machinery: links with genesis and treatment of breast cancer

Loss of normal growth control is a hallmark of cancer. Thus, understanding the mechanisms of tissue-specific, normal growth regulation and the changes that occur during tumorigenesis may provide insights of both diagnostic and therapeutic importance. Control of cell proliferation in the normal mammary gland is steroid hormone (estrogen and progestin)-dependent, involves complex interactions with other hormones, growth factors and cytokines and ultimately converges on activation of three proto-oncogenes (c-Myc, cyclin D1 and cyclin E1) that are rate limiting for the G1 to S phase transition during normal cell cycle progression. Mammary epithelial cell-specific overexpression of these genes induces mammary carcinoma in mice, while cyclin D1 null mice have arrested mammary gland development and are resistant to carcinoma induced by the neu/erbB2 and ras oncogenes. Furthermore, c-Myc, cyclins D1, E1 and E2 are commonly overexpressed in primary breast cancer where elevated expression is often associated with a more aggressive disease phenotype and an adverse patient outcome. This may be due in part to overexpression of these genes conferring resistance to endocrine therapies since in vitro studies provide compelling evidence that overexpression of c-Myc and to a lesser extent cyclin D1 and cyclin E1, attenuate the growth inhibitory effects of SERMS, antiestrogens and progestins in breast cancer cells. Thus, abnormal regulation of the expression of cell cycle molecules, involved in the steroidal control of cell proliferation in the mammary gland, are likely to be directly involved in the development, progression and therapeutic responsiveness of breast cancer. Furthermore, a more detailed understanding of these pathways may identify new targets for therapeutic intervention particularly in endocrine-unresponsive and endocrine-resistant disease.

American Society of Clinical Oncology 2007 update of recommendations for the use of tumor markers in breast cancer

PURPOSE

To update the recommendations for the use of tumor marker tests in the prevention, screening, treatment, and surveillance of breast cancer.

METHODS

For the 2007 update, an Update Committee composed of members from the full Panel was formed to complete the review and analysis of data published since 1999. Computerized literature searches of MEDLINE and the Cochrane Collaboration Library were performed. The Update Committee's literature review focused attention on available systematic reviews and meta-analyses of published tumor marker studies. In general, significant health outcomes (overall survival, disease-free survival, quality of life, lesser toxicity, and cost-effectiveness) were used for making recommendations. Recommendations and

CONCLUSIONS

Thirteen categories of breast tumor markers were considered, six of which were new for the guideline. The following categories showed evidence of clinical utility and were recommended for use in practice: CA 15-3, CA 27.29, carcinoembryonic antigen, estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, urokinase plasminogen activator, plasminogen activator inhibitor 1, and certain multiparameter gene expression assays. Not all applications for these markers were supported, however. The following categories demonstrated insufficient evidence to support routine use in clinical practice: DNA/ploidy by flow cytometry, p53, cathepsin D, cyclin E, proteomics, certain multiparameter assays, detection of bone marrow micrometastases, and circulating tumor cells.