Cyclin D1 in invasive breast carcinoma: favourable prognostic significance in unselected patients and within subgroups with an aggressive phenotype

Identification and validation of miRNA-target genes network in pediatric brain tumors

Alterations in miRNA levels have been observed in various types of cancer, impacting numerous cellular processes and increasing their potential usefulness in combination therapies also in brain tumors. Recent advances in understanding the genetics and epigenetics of brain tumours point to new aberrations and associations, making it essential to continually update knowledge and classification. Here we conducted molecular analysis of 123 samples of childhood brain tumors (pilocytic astrocytoma, medulloblastoma, ependymoma), focusing on identification of genes that could potentially be regulated by crucial representatives of OncomiR-1: miR-17-5p and miR-20a-5p. On the basis of microarray gene expression analysis and qRTPCR profiling, we selected six (WEE1, CCND1, VEGFA, PTPRO, TP53INP1, BCL2L11) the most promising target genes for further experiments. The WEE1, CCND1, PTPRO, TP53INP1 genes showed increased expression levels in all tested entities with the lowest increase in the pilocytic astrocytoma compared to the ependymoma and medulloblastoma. The obtained results indicate a correlation between gene expression and the WHO grade and subtype. Furthermore, our analysis showed that the integration between genomic and epigenetic pathways should now point the way to further molecular research.

Immunoexpression of HER2 pathway related markers in HER2 invasive breast carcinomas treated with trastuzumab

PURPOSE

We evaluated the immunoexpression of potential markers involved in the HER2 pathway in invasive breast carcinoma with HER2 amplification treated with trastuzumab.

METHODS

Samples of ninety patients diagnosed and treated at two public Brazilian hospitals with overexpressed invasive carcinoma between 2009 and 2018 were included. Several markers (Bcl-2, CDK4, cyclin D1, EGFR, IGF1, IGF-1R, MDM2, MUC4, p16, p21, p27, p53, PTEN, RA, TNFα, and VEGF) were immune analyzed in the tumor by immunohistochemistry and then correlated with clinicopathological variables.

RESULTS

Tumor sample expression results determined potential markers of good prognosis with statistically significant values: cyclin D1 with a nuclear grade, and recurrence; IGF-1 with tumor size, and death; p16 with a response after treatment; PTEN with a response after treatment, and death. Markers of poor prognosis: p53 with histological, and nuclear grade; IGF-1R with a compromised lymph node. The treatment resistance rate after trastuzumab was 40%; the overall survival was 4.13 years (95% CI 5.1-12.5) and the disease-free survival was 3.6 years (95% CI 5.1-13.1).

CONCLUSIONS

The tumor samples profile demonstrated that cyclin D1, IGF-1, p16, and PTEN presented the potential for a good prognosis and p53 and IGF-1R for worse.

The overexpression of cyclin D1 is a positive prognostic factor in advanced-stage breast carcinoma cases

OBJECTIVE

Cyclin D1 (CDDN1) is a protein required for mitotic cell cycle progression through the G1 phase, as well as a regulatory component of the cyclin-dependent kinases CDK4 and CDK6. In this study, we wanted to evaluate the relationship between CDDN1 expression and clinicopathological features in breast cancer (BC) cases and whether CDDN1 could be used as a prognostic biomarker for BC cases.

METHODS

A total of 70 cases, 30 cases each with limited and advanced-stage BC, and as the control group, 10 healthy breast tissue, without a cancer diagnosis, with examined for benign reasons (mammoplasty, breast reduction surgery, etc.) were included in this study. The pathological specimens from the cases were stained, immunohistochemically, and categorized as a "low" (L) group or a "high" (H) group for CDDN1 expression. The cases' clinicopathological features and survival rates were evaluated statistically, within a 95% of confidence interval, p<0.05, retrospectively.

RESULTS

The median follow-up period of the cases was 48.00 (range, 6-150) months. CDDN1 expression was significantly higher in advanced-stage BC cases than in normal breast tissue and limited-stage BC cases. The median overall survival (OS) was 96 months (CI 95%: 67.74-117.59) in the H-CDDN1 group, compared to the L-CDDN1 group not reached, but there was no relation (p>0.05). CDDN1 overexpression was more prominent in low-grade advanced BC cases (p=0.004). The median OS of advanced-stage BC cases with Grade 1 was significantly longer than those with other grades (p=0.04).

CONCLUSION

Our results suggest that CDDN1 expression can be used as a potentially appropriate positive prognostic biomarker for advanced-stage BC cases.

Cyclin D1 expression in ganglioglioma, pleomorphic xanthoastrocytoma and pilocytic astrocytoma

Ganglioglioma, pleomorphic xanthoastrocytoma (PXA) and pilocytic astrocytoma are rare brain neoplasms with frequent activation of mitogen-activated protein (MAP) kinase pathway. A downstream marker of MAP-kinase pathway activation is cyclin D1. However, the expression of cyclin D1 has not been studied in the differential diagnosis between these brain tumors. The aim of this work is to compare the expression of cyclin D1 in ganglioglioma, PXA, pilocytic astrocytoma. We also compared cyclin D1 expression in giant cell glioblastoma and in IDH wild type glioblastoma. Our work shows that roughly half of gangliogliomas have ganglion cells stained by cyclin D1 while two third of PXA have pleormophic cells stained by cyclin D1 and 15% of giant cell glioblastoma have pleomorphic cells stained by cyclin D1 (p < 0.001). Cyclin D1 never stains normal neurons either in the adjacent cortex of circumscribed tumor, or in entrapped neurons in IDH wild type glioblastomas. The expression of cyclin D1 is correlated to the presence of BRAF V600E mutation in ganglioglioma and PXA (p = 0.002). To conclude, cyclin D1 positivity might be used to confirm the neoplastic nature of ganglion cells. Cyclin D1 is expressed in most cases of BRAF V600E mutated gangliogliomas but also in cases without BRAF mutations suggesting an activation of MAP-kinase pathway through another way. Cyclin D1 immunohistochemistry has currently no or little role in the differential diagnosis of pilocytic astrocytoma. Its role in the differential diagnosis between PXA and giant cell glioblastoma needs to be further investigated on external series.

High Expression of Cyclin D1 is an Independent Marker for Favorable Prognosis in Middle Eastern Breast Cancer

Purpose

The cyclin D1 protein regulates cell cycle progression which is mediated by its interactions with cyclin-dependent kinases. Over-expression of cyclin D1 has been observed in several human cancers. This study was conducted to evaluate cyclin D1 expression in a large cohort of Middle Eastern breast cancers and determine its prognostic significance.

Patients and Methods

Cyclin D1 expression was assessed immunohistochemically and its association with clinico-pathological parameters was analyzed in 1003 breast cancer patients.

Results

Cyclin D1 was over-expressed in 59.4% (596/1003) of cases and significantly associated with a subset of breast cancers having favorable prognostic features, such as low grade (p < 0.0001), low stage (p = 0.0276), estrogen receptor (p < 0.0001) and progesterone receptor positive (p < 0.0001) tumors. An inverse association was found with triple negative breast cancers (p < 0.0001). More importantly, cyclin D1 expression was an independent predictor of favorable overall survival in our cohort (hazard ratio = 0.70; 95% confidence interval = 0.50–0.98; p = 0.0395). Also, tumors that highly expressed cyclin D1 had a longer recurrence-free survival. However, this significant association was seen only in univariate analysis. We also found cyclin D1 to be associated with phospho-Rb in luminal subtype of breast cancer and co-expression of both these markers was an independent predictor of luminal A breast cancer.

Conclusion

Our results reinforced the role of cyclin D1 in breast cancer pathology and revealed its expression as a valuable independent prognostic indicator for breast cancer from Middle Eastern ethnicity.

Anti-proliferative effects of cell wall, cytoplasmic extract of Lactococcus lactis and nisin through down-regulation of cyclin D1 on SW480 colorectal cancer cell line

Background and Objectives:

Colorectal cancer is one of the most types of cancer. Researchers have shown that lactic acid bacteria have antitumor activity. The cell wall of Lactococcus lactis, as the bacterial cytoplasmic extract and nisin can affect the proliferation of cancer cells. Since cyclin D1 plays an important role in the progression of the cell cycle, its regulation can also be a therapeutic approach. We investigated the antiproliferative effect of cell wall, cytoplasmic extract and nisin on SW480 cancer cell line and the expression level of cyclin D1 gene in treated cancer cells.

Materials and Methods:

SW480 cell lines were treated with different concentrations of bacterial cell wall, cytoplasmic extract and nisin. MTT test was also performed. The expression level of cyclin D1 gene was determined using Real time PCR. Data were analyzed using Graph Pad Prism software.

Results:

The growth rate of cancer cells treated with nisin has significantly decreased compared to the cancer cells treated by other two substances (p< 0.05). Survival rates of the cancer cells treated by nisin at a concentration of 2000 μg, cytoplasmic extract, and cell wall were 34%, 47% and 49%, respectively. Real-time PCR results showed that cyclin D1 mRNA expression has significantly decreased in nisin treated sw480 cells (P<0.05).

Conclusion:

The results of this study show that nisin, bacterial cytoplasmic extract, and bacterial cell wall have antiproliferative effects, which are associated with the decreased expression of cyclin D1 in SW480 cell line.

Upregulation of cyclin D1 can act as an independent prognostic marker for longer survival time in human nasopharyngeal carcinoma

Background

Cyclin D1 is an essential part of oncogenic transformation. We previously proved that cyclin D1 was upregulated in nasopharyngeal carcinoma (NPC) and promoted the NPC cell proliferation. But the association between cyclin D1 and the clinical outcome of NPC has not yet been determined. The study explores the possible relevance between the cyclin D1 expression and clinical parameters and its predictive value of prognosis in NPC patients.

Methods

We analyzed the clinical data from 379 NPC patients and 112 non‐NPC patients in our previous study, which made further statistics. Receiver operating curve (ROC) was applied to select the optimal cutoff points. By analyzing the clinical data from 101 NPC patients using Chi‐squared test, we estimated the relationship between the cyclin D1 expression level and clinicopathological parameters. We also used Kaplan‐Meier method and log‐rank test assess and compared the disease‐free survival (DFS) rate and overall survival (OS) rate. The Cox proportional hazards model was adopted to perform the univariate and multivariate analyses.

Result

Receiver operating curve analysis reported that cyclin D1 was used to differentiate between NPC patients and non‐NPC patients (P < .001, sensitivity: 53.6%, specificity: 85.7%, AUC = 0.752). Cyclin D1 was positively correlated with lymph node metastasis (P = .015). A survival analysis of the 101 NPC patients indicated that the positive expression of cyclin D1 was predictive of a good prognosis (DFS: P = .010, OS: P = .019). Multivariate analysis showed that cyclin D1 could be used independently to predict NPC patients' prognosis (DFS: P = .038).

Conclusion

The overexpression of cyclin D1 is a good prognostic marker for NPC.

The prognostic value of cyclin D1 expression in the survival of cancer patients: A meta-analysis

BACKGROUND

The relationship between the expression of cyclin D1 and cancer prognosis and outcomes in different malignancies has not been fully elucidated.

AIMS

In the presented meta-analysis, we assessed the association between the expression level of cyclin D1 with overall survival (OS) in several cancers.

METHODS

Eligible studies were identified using PubMed, EMBase, Scopus, Web of Sciences and Cochrane Library databases. For the prognostic meta-analysis, study-specific hazard ratios (HRs) of tissue cyclin D1 for survival were obtained. Finally we pooled data derived from one hundred and eight studies comprising 19,224 patients with 10 different cancer types.

RESULTS

In the pooled analysis, high expression of cyclin D1 was significantly related to a poor OS with a pooled HR of 1.11 (95% CI: 1.02-1.20, P = 0.015; random-effects). Sub-group analysis revealed that high expression of cyclin D1 was related to worse OS of head and neck cancers (HR = 2.08, 95% CI: 1.75-2.47; P < 0.001), but not in breast (HR = 1.033, 95% CI: 0.873-1.223, P = 0.702), gastrointestinal (HR = 1.025, 95% CI:0.824-1.275; P = 0.825), bladder (HR = 0.937, CI: 0.844-1.041; P = 0.225) and in lung cancer patients (HR = 1.092, CI: 0.819-1.455; P = 0.549).

CONCLUSION

Further large, prospective, and well-designed trials are warranted to elucidate the precise clinical importance of cyclin D1 overexpression in the prognosis of cancer patients receiving different treatment regimens.

A comprehensive genomic meta-analysis identifies confirmatory role of OBSCN gene in breast tumorigenesis

The giant multifunctional protein "OBSCURIN" is encoded by OBSCN gene and is mostly expressed in cardiac and other skeletal muscles responsible for myofibrils organization. Loss of OBSCURIN affects the entire downstream pathway proteins vital for various cellular functions including cell integration and cell adhesion. The OBSCN gene mutations are more frequently observed in various muscular diseases, and cancers. Nevertheless, the direct role of OBSCN in tumorigenesis remains elusive. Interestingly, in clinical breast cancer samples a significant number of function changing mutations have been identified in OBSCN gene. In this study, we identified a significant role of OBSCN by conducting an integrative analysis of copy number alterations, functional mutations, gene methylation and expression data from various BRCA cancer projects data available on cBioPortal and TCGA firebrowse portal. Finally, we carried out genetic network analysis, which revealed that OBSCN gene plays a significant role in GPCR, RAS, p75 or Wnt signaling pathways. Similarly, OBSCN gene interacts with many cancer-associated genes involved in breast tumorigenesis. The OBSCN gene probably regulates breast cancer progression and metastasis and the prognostic molecular signatures such as copy number alterations and gene expression of OBSCN may serve as a tool to identify breast tumorigenesis and metastasis.

Prognostic significance of cyclin D1 protein expression and gene amplification in invasive breast carcinoma

The oncogenic capacity of cyclin D1 has long been established in breast cancer. CCND1 amplification has been identified in a subset of patients with poor prognosis, but there are conflicting data regarding the predictive value of cyclin D1 protein overexpression. This study was designed to analyze the expression of cyclin D1 and its correlation with CCND1 amplification and their prognostic implications in invasive breast cancer. By using the tissue microarray technique, we performed an immunohistochemical study of ER, PR, HER2, p53, cyclin D1, Ki67 and p16 in 179 invasive breast carcinoma cases. The FISH method was performed to detect HER2/Neu and CCND1 amplification. High cyclin D1 expression was identified in 94/179 (52%) of invasive breast cancers. Cyclin D1 overexpression and CCND1 amplification were significantly associated (p = 0.010). Overexpression of cyclin D1 correlated with ER expression, PR expression and Luminal subtypes (p<0.001), with a favorable impact on overall survival in the whole series. However, in the Luminal A group, high expression of cyclin D1 correlated with shorter disease-free survival, suggesting that the prognostic role of cyclin D1 depends on the molecular subtype. CCND1 gene amplification was detected in 17 cases (9%) and correlated significantly with high tumor grade (p = 0.038), high Ki-67 protein expression (p = 0.002), and the Luminal B subtype (p = 0.002). Patients with tumors with high amplification of CCND1 had an increased risk of recurrence (HR = 2.5; 95% CI, 1.2-4.9, p = 0.01). These findings suggest that CCND1 amplification could be useful for predicting recurrence in invasive breast cancer.

High expression of cyclin D1 is associated to high proliferation rate and increased risk of mortality in women with ER-positive but not in ER-negative breast cancers

Purpose

Cyclin D1 has a central role in cell cycle control and is an important component of estrogen regulation of cell cycle progression. We have previously shown that high cyclin D expression is related to aggressive features of ER-positive but not ER-negative breast cancer. The aims of the present study were to validate this differential ER-related effect and furthermore explore the relationship between cyclin D overexpression and CCND1 gene amplification status in a node-negative breast cancer case–control study.

Methods

Immunohistochemical nuclear expression of cyclin D1 (n = 364) and amplification of the gene CCND1 by fluorescent in situ hybridization (n = 255) was performed on tissue microarray sections from patients with T1-2N0M0 breast cancer. Patients given adjuvant chemotherapy were excluded. The primary event was defined as breast cancer death. Breast cancer-specific survival was analyzed in univariate and multivariable models using conditional logistic regression.

Results

Expression of cyclin D1 above the median (61.7%) in ER breast cancer was associated with an increased risk for breast cancer death (OR 3.2 95% CI 1.5–6.8) also when adjusted for tumor size and grade (OR 3.1). No significant prognostic impact of cyclin D1 expression was found among ER-negative cases. Cyclin D1 overexpression was significantly associated to high expression of the proliferation markers cyclins A (ρ 0.19, p = 0.006) and B (ρ 0.18, p = 0.003) in ER-positive tumors, but not in ER-negative cases. There was a significant association between CCND1 amplification and cyclin D1 expression (p = 0.003), but CCND1 amplification was not statistically significantly prognostic (HR 1.4, 95% CI 0.4–4.4).

Conclusion

We confirmed our previous observation that high cyclin D1 expression is associated to high proliferation and a threefold higher risk of death from breast cancer in ER-positive breast cancer.

Integrated analysis of differentially expressed genes and pathways in triple‑negative breast cancer

Triple‑negative breast cancer (TNBC) is a heterogeneous disease characterized by an aggressive phenotype and reduced survival. The aim of the present study was to investigate the molecular mechanisms involved in the carcinogenesis of TNBC and to identify novel target molecules for therapy. The differentially expressed genes (DEGs) in TNBC and normal adjacent tissue were assessed by analyzing the GSE41970 microarray data using Qlucore Omics Explorer, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes. Pathway enrichment analyses for DEGs were performed using the Database for Annotation, Visualization and Integrated Discovery online resource. A protein‑protein interaction (PPI) network was constructed using Search Tool for the Retrieval of Interacting Genes, and subnetworks were analyzed by ClusterONE. The PPI network and subnetworks were visualized using Cytoscape software. A total of 121 DEGs were obtained, of which 101 were upregulated and 20 were downregulated. The upregulated DEGs were significantly enriched in 14 pathways and 83 GO biological processes, while the downregulated DEGs were significantly enriched in 18 GO biological processes. The PPI network with 118 nodes and 1,264 edges was constructed and three subnetworks were extracted from the entire network. The significant hub DEGs with high degrees were identified, including TP53, glyceraldehyde‑3‑phosphate dehydrogenase, cyclin D1, HRAS and proliferating cell nuclear antigen, which were predominantly enriched in the cell cycle pathway and pathways in cancer. A number of critical genes and pathways were revealed to be associated with TNBC. The present study may provide an improved understanding of the pathogenesis of TNBC and contribute to the development of therapeutic targets for TNBC.

Dual Inhibition of Key Proliferation Signaling Pathways in Triple-Negative Breast Cancer Cells by a Novel Derivative of Taiwanin A

The treatment of breast cancer cells obtained by blocking the aberrant activation of the proliferation signaling pathways PI3K/Akt/mTOR and MEK/ERK has received considerable attention in recent years. Previous studies showed that Taiwanin A inhibited the proliferation of several types of cancer cells. In this study, we report that 3,4-bis-3,4,5-trimethoxybenzylidene-dihydrofuran (BTMB), a novel derivative of Taiwanin A, significantly inhibited the proliferation of triple-negative breast cancer (TNBC) cells both in vitro and in vivo The results show that BTMB inhibited the proliferation of human TNBC cells by the induction of cell-cycle arrest and apoptosis in a dose-dependent fashion. BTMB inhibited the expression of β-catenin, cdc2 and the cell-cycle regulatory proteins, cyclin A, cyclin D1, and cyclin E. The mechanism of action was associated with the suppression of cell survival signaling through inactivation of the Akt and ERK1/2 signaling pathways. Moreover, BTMB induced cell apoptosis through an increase in the expression of BAX, cleaved caspase-3, and cleaved PARP. Moreover, BTMB inhibited TNBC cell colony formation and sensitized TNBC cells to cisplatin, a chemotherapeutic drug. In a TNBC mouse xenograft model, BTMB significantly inhibited the growth of mammary carcinomas through decreased expression of cyclin D1. BTMB was shown to significantly suppress the growth of mammary carcinoma and therefore to have potential as an anticancer therapeutic agent. Mol Cancer Ther; 16(3); 480-93. ©2016 AACR.

Quercetin reduces cyclin D1 activity and induces G1 phase arrest in HepG2 cells

Quercetin is able to inhibit proliferation of malignant tumor cells; however, the exact mechanism involved in this biological process remains unclear. The current study utilized a quantitative proteomic analysis to explore the antitumor mechanisms of quercetin. The leucine of HepG2 cells treated with quercetin was labeled as d3 by stable isotope labeling by amino acids in cell culture (SILAC). The isotope peaks of control HepG2 cells were compared with the d3-labeled HepG2 cells by mass spectrometry (MS) to identify significantly altered proteins. Reverse transcription-polymerase chain reaction (RT-PCR) and western blot analyses were subsequently employed to verify the results of the MS analysis. A flow cytometry assay was designed to observe the influence of various quercetin treatment concentrations on the cell cycle distribution of HepG2 cells. The results indicated that quercetin is able to substantially inhibit proliferation of HepG2 cells and induce an obvious morphological alteration of cells. According to the MS results, the 70 credibly-changed proteins that were identified may play important roles in multiple cellular processes, including protein synthesis, signaling, cytoskeletal processes and metabolism. Among these functional proteins, the expression of cyclin D1 (CCND1) was found to be significantly decreased. RT-PCR and western blot analyses verified the SILAC-MS results of decreased CCND1 expression. In summary, flow cytometry revealed that quercetin is able to induce G1 phase arrest in HepG2 cells. Based on the aforementioned observations, it is suggested that quercetin exerts antitumor activity in HepG2 cells through multiple pathways, including interfering with CCND1 gene expression to disrupt the cell cycle and proliferation of HepG2 cells. In the future, we aim to explore this effect in vivo.

Elevated preoperative neutrophil-to-lymphocyte ratio predicts poor disease-free survival in Chinese women with breast cancer

Inflammation and tumor immune microenviroment are critical factors for prognosis in numerous cancers. The aim of this study was to determine the prognostic value of preoperative neutrophil-to-lymphocyte ratio (NLR) in breast cancer. We performed a retrospective analysis of 487 patients diagnosed with primary breast cancer at Shanghai Ruijin hospital from January 2009 to December 2010. Hematological parameters before surgery, clinicopathological data, and survival status were obtained. Survival analysis was used to evaluate the prognostic value of NLR. The optimal cutoff value was determined as 1.93 for NLR and the median follow-up time was 55.0 months. On univariate analysis, patients with high NLR (>1.93) had worse 5-year disease-free survival (DFS) compared to those with low NLR (77.9 vs 88.0 %, p = 0.002). Regarding overall survival, there was no significant difference between patients with high NLR and low NLR, with 5-year overall survival of 90.8 and 91.7 % (p = 0.707). In triple-negative breast cancer, patients with high NLR was associated with worse 5-year DFS compared with patients with low NLR (63.4 vs 84.9 %, p = 0.040). Mutivariate analysis revealed that NLR was an independent prognostic factor for DFS in breast cancer (HR = 1.867, 95 % confidence interval; (95%CI) = 1.155-3.017, p = 0.011). Preoperative NLR is an independent predictor of DFS in breast cancer patients, especially in triple-negative subtype. Further studies are required to validate the prognostic value of NLR before clinical application.

No difference in CCND1 gene expression between breast cancer patients with and without lymph node metastasis in a Southern Brazilian sample

The Cyclin D1 protein has been extensively studied over the last decades, for its various roles in physiological processes, both in normal and cancer cells. Gene amplifications and overexpression of CCND1 are frequently reported in several types of cancers, including breast carcinomas, showing the increasing relevance of Cyclin D1 in tumorigenesis. Little is known about the role of this protein in the metastatic process, and the main objective of this study was to evaluate the importance of the CCND1 as a potential marker of tumor progression in breast carcinomas, in a sample collected in Southern Brazil. We studied 41 samples of formalin-fixed paraffin-embedded tissue sections from invasive ductal breast carcinomas subdivided into metastatic (n = 19) and non-metastatic (n = 22) tumors. Gene expression analysis was performed through Quantitative Real-Time PCR and immunohistochemistry. In spite of the higher expression levels of CCND1 mRNA and protein in tumors when compared with the control samples, no differences were observed between the metastatic and non-metastatic groups, suggesting that, in these samples, the expression of CCND1 has no significant influence on the metastatic process. Further studies must be performed in an attempt to clarify the diagnostic and prognostic value of Cyclin D1 in breast cancers, as well as the mechanisms that trigger its overexpression in tumors.

Prognosis of lymph node-negative breast cancer: Association with clinicopathological factors and tumor associated gene expression

The aim of the present study was to investigate the association between the prognosis of lymph node-negative breast cancer patients and clinicopathological factors, as well as the association between tumor-associated gene expression and prognosis. Clinical data and survival information was collected for 341 patients with lymph node-negative breast cancer, admitted to the Cancer Hospital of the Chinese Academy of Medical Sciences (Beijing, China) from 1995 to 1999. Kaplan-Meier survival analysis and Log-rank tests were used to evaluate the association of clinical parameters and prognosis. In addition, the gene expression of HER2, TOP2A and CCND1 in patients with good [disease-free survival (DFS), ≥5 years] and poor (DFS, <5 years) prognoses was analyzed. The clinicopathological factors of the 341 lymph node-negative breast cancer patients were determined. The 5-year DFS and overall survival rate (OS) in patients >35 years old was higher as compared with those of patients under the age of 35. Tumor size significantly affected the 5-year DFS. Patients with smaller tumors (≤2 cm) had a significantly higher DFS rate as compared with patients with larger tumors (>2 cm). Estrogen receptor (ER)-positive patients had a significantly higher 5-year DFS and OS rate as compared with ER-negative patients. By contrast, there were no significant differences in the 5-year DFS and OS rates between progesterone receptor-positive and -negative patients. The 5-year DFS and OS rates were significantly higher in patients treated with adjuvant hormone therapy, as compared with patients without hormone therapy. The expression of HER2 protein was higher in patients with a poor prognosis as compared with those with a good prognosis; however, there were no differences in the protein expression of CCND1 and TOP2A between patients with a good and poor prognosis. The results of quantitative polymerase chain reaction showed that the gene expression of HER2 and CCND1 was higher in patients with a poor prognosis as compared with that in patients with a good prognosis. TOP2A gene expression was not significantly different between patients with a poor and good prognosis. The age at diagnosis, tumor size, ER status and hormone therapy were associated with prognosis in patients with lymph node-negative breast cancer. The molecular biomarker, HER2, but not CCND1 or TOP2A, may be a critical factor for predicting prognosis.