BCL2 (B-cell leukemia/lymphoma 2) gene functions as antiapoptotic regulatory element and known to be associated with tumorigenesis. The SNP-938 (C>A) (rs2279115), located in the inhibitory P2 promoter of the BCL2 gene, influences differential binding affinities of transcriptional factors thereby affecting BCL2 expression. The present study is an attempt to evaluate the association between BCL2(-938C>A) polymorphism and clinical characteristics of breast cancer patients as well as to analyze BCL2 expression and Ki67 proliferation index with respect to the genotypes. One hundred ten primary breast cancer tumor tissues were genotyped for -938 C>A polymorphism through PCR-RFLP method as well as evaluated for BCL2 expression and ki67 proliferation index by immunohistochemistry. Evaluation of apoptosis level was performed by flowcytometry. The results revealed that AA genotype was associated with an increased risk (AA Vs AC + CC) by 2.86-fold (p = 0.07) for breast cancer development which reflected in elevated A allele frequency also. AA genotype was found to be predominant among BCL2 positive tumors as compared to BCL2 negative tumors. Further, AA genotype was found to be associated with advanced stage tumors, node positive status, and high Ki67 proliferation index compared to CA and CC genotypes indicating that elevated expression of BCL2 gene in the presence of A allele might be associated with decreased apoptosis and enhanced proliferation rate. AA genotype of BCL2-938C>A polymorphism might influence BCL2 gene expression there by associated with elevated risk for breast cancer progression. Probably, failure of apoptosis due to enhanced expression and antiapoptotic protein BCL2 might promote malignant growth.

Cell polarity and cell-cell adhesion play a critical role in the regulation of normal tissue architecture and function. Disruption of cell adhesion and cell polarity is often associated with neoplastic tumors. Loss of apical-basal polarity in epithelial cells is one of the hallmarks of aggressive and invasive cancers. Several polarity proteins including atypical protein kinase C (aPKC), Par 6, Par 3, and Lethal giant larvae (Lgl, the human homologues of which are called Hugl 1 and Hugl 2) are localized at the leading edge of migrating cells, and play critical roles during directional migration. Herein, we investigated the expression of aPKC, Par 6, Par 3, Hugl 1, and Hugl 2 in lung squamous cell carcinoma (SqCC). An inverse correlation was observed between the expression of Hugl 1 and lung SqCC progression. Results of immunohistochemistry and real-time RT-PCR analyses showed that reduced expression of Hugl 1 predicts poor survival in lung SqCC patients. The expression of Hugl 1 was inversely correlated with both overall survival rate and tumor stage. On the other hand, no associations were observed between the expressions of Hugl 2, Par 6, and Par 3 and lung SqCC progression. These findings indicate that the reduced expression of Hugl 1 could be considered as a poor prognostic factor in human lung cancers.

The aim of this study is to investigate IGF-1, IGF-1R, and IGFBP-3 methylations in esophageal carcinoma (EC) patients and their relationship with the development and prognosis of EC. This study population consisted of 264 patients (case group) whom EC radical resection was performed and 283 healthy individuals (control group). Methylation-specific PCR (MSP) detected the methylation status of IGF-1, IGF-1R, and IGFBP-3 in the peripheral blood in both groups. The expressions of IGF-1, IGF-1R, and IGFBP-3 in EC and adjacent normal tissues were detected by immunohistochemistry (IHC). The methylation rates of IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 in the case group were higher than those in the control group (all P < 0.05). Additionally, there were statistical significances for the methylation rates of IGF-1, IGF-1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 IGF-1 among patients of different clinicopathological features (all P < 0.05). The positive expression rates of IGF-1 and IGF-1R in EC were significantly higher than those in adjacent normal tissues (both P < 0.001), and the rate of IGFBP-3 in EC was significantly lower than that in adjacent normal tissues (P < 0.05). Correlation analysis showed that IGF-1 and IGF1R gene promoter methylation was positively correlated with the positive expressions of IGF-1 (r = 0.139, P = 0.024) and IGF-1R (r = 0.135, P = 0.028), while the IGFBP3 methylation was negatively correlated with the positive expression of IGFBP3 (r = -0.133, P = 0.031). The positive expressions of IGF-1, IGF-1R, and IGFBP-3 were related to different clinicopathological features (all P < 0.05). Cox multivariate analysis results showed that methylation status of IGF-1, IGF-1R, and IGF-1 + IGF1R + IGFBP3 ; expressions of IGF-1 and IGF-1R protein; infiltration depth; and lymph node metastasis (LNM) were independent factors of EC prognosis. Our study demonstrated that methylation of IGF-1, IGF1R, IGFBP3, and IGF-1 + IGF1R + IGFBP3 was closely linked with the occurrence of EC and patients' clinicopathological features. Besides, the methylation status of the target genes and the expressions of IGF-1 and IGF-1R protein were independent factors of EC prognosis, which could provide a direction for the prognosis and treatment of EC.

The aim was to investigate the function of fibroblast growth factor receptor 4 (FGFR4) in gastric cancer (GC) and explore the treatment value of agent targeted to FGFR4. Function assays in vitro and in vivo were performed to investigate the discrepancy of biological features among the GC cells with different expression of FGFR4. GC cells were treated with the single and combination of PD173074 (PD, an inhibitor of FGFR4) and 5-fluorouracil (5-Fu). The invasion ability were stronger, and the apoptosis rates were lower in MGC803 and BGC823 cells treated with FGFR4-LV5 (over-expression of FGFR4 protein) (P < 0.05). The proliferation ability of GC cells is reduced when treated by the single and combination of 5-Fu and PD while that of the FGFR4-LV5 group was less inhibited compared with control group (P < 0.05). The apoptosis rates are remarkably increased in GC cells treated with the single and combination of 5-Fu and PD (P < 0.05). However, the apoptosis rate obviously is reduced in GC cells treated with FGFR4-LV5 compared with control group (P < 0.05). The expression of PCNA and Bcl-XL is remarkably decreased, and the expression of Caspase-3 and cleaved Caspase-3 is obviously increased in GC cells treated with the single and combination of 5-Fu and PD. The tumor volumes of nude mice in FGFR4-LV5 group were much more increased (P < 0.05). The over-expression of FGFR4 enhanced the proliferation ability of GC in vitro and in vivo. The combination of 5-Fu and PD exerted synergetic effect in weakening the proliferation ability and promoting apoptosis in GC cells, while the over-expression of FGFR4 might inhibit the efficacy of two drugs.

Interleukin-27 (IL-27) has been recognized as a pleiotropic cytokine with both pro- and anti-inflammatory properties. However, there are no data about the role of IL-27 polymorphism in the development of cervical cancer. A hospital-based case-control study was conducted in 380 patients with cervical cancer and 380 healthy controls to investigate the possible associations of IL-27 gene polymorphisms (-964A/G, 2905T/G, and 4730T/C), with susceptibility to cervical cancer and clinical outcome. Our results suggested that the IL-27 2905T/G was significantly associated with a decreased risk of cervical cancer (TG vs. TT, odds ratio (OR) = 0.77; 95 % confidence interval (CI) = 0.60-0.86; GG vs. TT, OR = 0.95; 95 % CI = 0.72-0.96; TG+GG vs. TT, OR = 0.87; 95 % CI = 0.65-0.94). However, the genotype and allele frequencies of IL-27 (-964A/G and 4730T/C) polymorphisms in cervical cancer patients were not significantly different from controls. Further analysis showed IL-27 2905T/G genotypes were associated with advanced tumor stages of cervical cancer patients. More interestingly, the IL-27 2905T/G genotypes were statistically significantly associated with the survival in cervical cancer patients. Our results showed that the IL-27 2905T/G genotypes were associated with decreased susceptibility and development of cervical cancer in Chinese Han population.

Notch signaling was associated with a variety of cancers but was not comprehensively studied in clear-cell renal cell carcinoma (ccRCC). We have in this study studied the genetic alteration (mutation and copy number variance) of Notch gene set in the Cancer Genome Atlas (TCGA) Kidney Renal Clear Cell Carcinoma (KIRC) database. We found that Notch pathway was frequently altered in ccRCC. The Notch gene set was genetically altered in 182 (44%) of the 415 ccRCC patients. CNV was the predominant type of alteration in most genes. Alterations in KAT2B and MAML1 occurred in 13% and 19% of patients, respectively, both of which were functionally active in ccRCC. Deletion of VHL was exclusively found in cases with Notch alteration. Overall survival was longer in ccRCC patients with altered-Notch pathway. The median survival was 90.41 months in Notch-altered cases and 69.15 in Notch-unaltered cases (P = 0.0404). The median disease free time was 89.82 months in Notch-altered cases and 77.27 months in in Notch-unaltered cases (P = 0.935). Conclusively, Notch signaling was altered in almost half of the ccRCC patients and copy number variances in MAML1 and KAT2B were predominant changes. These findings broadened our understanding of the role of Notch in ccRCC.

Osteosarcoma is one of the most common bone malignancies in adolescents, and hereditary factors may influence its susceptibility. We assessed the association between XRCC3 Thr241Met polymorphism and susceptibility to osteosarcoma in a Chinese population. Between May 2012 and May 2014, a total of 136 osteosarcoma patients and 136 healthy control subjects were included in our study. The XRCC3 Thr241Met polymorphism was analyzed using a polymerase chain reaction restriction fragment length polymorphism assay. By multiple logistic regression analysis, individuals carrying the Met/Met genotype of XRCC3 Thr241Met were at significantly increased risk of osteosarcoma when compared with the Thr/Thr (OR = 2.50, 95%CI = 1.13-5.66). The Thr/Met+Met/Met genotype of XRCC3 Thr241Met was furthermore found to be correlated with an elevated increased risk of osteosarcoma when compared with the Thr/Thr genotype (OR = 1.71, 95%CI = 1.03-2.87), and Met/Met genotype of XRCC3 Thr241Met was associated with an increased risk of osteosarcoma compared to the Thr/Thr (OR = 3.50, 95%CI = 1.51-8.79). In conclusion, our study firstly reports that XRCC3 Thr241Met gene polymorphism is associated with an elavated risk of osteosarcoma.

We performed a case-control study to investigate the association between single nucleotide polymorphisms in the MTHFR gene (677C/T and 1298A/C) and risk of breast cancer. This case-control study included 216 breast cancer cases and 216 controls. The MTHFR 677C/T and 1298A/C gene polymorphisms were assessed by polymerase chain reaction restriction fragment length polymorphism. We observed an increased likelihood of breast cancer patients having a higher age at menarche and first live birth, and a greater family history of breast cancer, especially among first-degree relatives. In addition, individuals with the TT genotype of MTHFR 677C/T were associated with increased risk of breast cancer by logistic regression analysis; the adjusted odds ratio (95%CI) was 3.05 (1.17-8.87). In conclusion, the results of our study indicated that the MTHFR C677T gene polymorphism could play a role in the development of breast cancer.

The aim of this study was to investigate the expression of LRRC4 in nasopharyngeal carcinomas, nasopharyngeal precancerous lesions, and nasopharyngitis as well as the clinical significance of LRRC4. Fifty patients with nasopharyngeal carcinoma were selected as study subjects; 28 patients with chronic nasopharyngitis and 22 patients with nasopharyngeal precancerous lesions served as controls. Immunohistochemical analysis was used to study protein expression of LRRC4; the relation between LRRC4 expression and the clinical stage and histopathological features of nasopharyngeal carcinoma was also analyzed. The LRRC4 expression manifested itself as yellow staining in the cytoplasm or nucleus. LRRC4 was strongly expressed in nasopharyngeal epithelial tissues of patients with chronic nasopharyngitis and in nasopharyngeal precancerous lesions; the rates of positive results were 82.1 and 81.8%, respectively. LRRC4 was weakly expressed in nasopharyngeal carcinoma tissues, at a rate of 10% positive results (P< 0.001); there was no significant difference in the expression of LRRC4 among different clinical stages and pathological grades. Therefore, disappearance of LRRC4 expression is a major feature of nasopharyngeal carcinoma.

MicroRNA-106b (miR-106b) is overexpressed in various types of cancers and is associated with the regulation of carcinogenic processes. However, its clinical significance in cutaneous melanoma has not been reported. qRT-PCR was performed to examine the expression of miR-106b in 15 cases of dysplastic nevi, 17 cases of melanoma metastases, and 97 cases of primary cutaneous melanoma tissue samples. Survival rate was determined with Kaplan-Meier and statistically analyzed with the log-rank method between groups. Survival data were evaluated through multivariate Cox regression analysis. Significant differences in miR-106b expression were shown between dysplastic nevi and primary cutaneous melanomas (P < 0.01), between primary melanomas and metastatic cutaneous melanomas (P < 0.01), and between primary cutaneous melanomas and metastatic cutaneous melanomas (P < 0.001). We found that high miR-106b expression was correlated with Breslow thickness (P = 0.002), tumor ulceration (P = 0.002), and advanced clinical stage (P < 0.001). The patients with high miR-106b expression showed shorter 5-year overall survival than those with low miR-106b expression (P = 0.02; log-rank test). Multivariate regression analysis showed that the status of miR-106b expression was an independent prognostic factor for overall survival (HR = 2.09, 95%CI: 1.11-10.26, P = 0.02). This study showed that miR-106b may contribute to the progression of cutaneous melanoma and its up-regulation may be independently associated with poor prognosis of cutaneous melanoma. This suggests that miR-106b might serve as a promising biological marker for further risk stratification in the management of cutaneous melanoma.

microRNA-218 (miR-218) is a vertebrate-specific miRNA that plays a crucial role in tumorigenesis and tumor progression. This study analyzed the miR-218 expression level and clinical significance in pancreatic cancer. One hundred and seven pairs of pancreatic cancer and adjacent normal tissues were analyzed by quantitative reverse-transcriptase polymerase chain reaction. The correlation between miR-218 expression and clinicopathological characters was determined by the two-sample Student t-test. The survival correlations were analyzed by the Kaplan-Meier method and Cox proportional hazards model. The relative expression of miR-218 in pancreatic cancer tissues (2.63 ± 1.59) was significantly lower than that in matched noncancerous pancreatic tissues (6.52 ± 2.50, P < 0.001). The low expression of miR-218 in the pancreatic cancer tissues were strongly correlated with the TNM classification (P = 0.02), distant metastasis (P = 0.001), and tumor differentiation (P = 0.003). The low level of miR-218 expression was significantly correlated with the shorter overall survival time of pancreatic cancer patients (5-year overall survival rate: 7.5 vs 34.9%; log-rank test: P < 0.001). Multivariate analyses confirmed that a low level of miR-218 expression was an independent predictor of poor prognosis in pancreatic cancer patients (Hazard ratio: 7.24; 95% confidence interval: 2.01-18.28; P = 0.007). Our findings suggested a significant downregulation in the expression of miR-218; this might have considerable potential value in the prognosis for pancreatic cancer.

The aim of this study was to establish a metastatic human neuroblastoma (NB) mouse model by xenograft in order to study the metastatic mechanisms of NB. A human NB cell line was obtained from a 5-year-old patient and cultured in vitro. A suspension of these cells was subcutaneously inoculated into nude mice at the right flank next to the forelimb. The biological characteristics of the developed subcutaneous and metastatic tumors were analyzed by hematoxylin and eosin staining. The expression of the tumor marker neuron-specific enolase was determined by immunohistochemistry, and the invasive ability of metastatic tumors was examined by a Matrigel invasion assay. DNA microarray analyses were performed to examine the metastasis-related gene expression. Our results showed that tumors grew in 75% of the mice injected with NB cells and the rate of metastasis was 21%. The xenograft tumors retained the morphological and biological characteristics of the NB specimen from the pediatric patient. Neuron-specific enolase was highly expressed in both subcutaneous and metastatic tumors. The metastatic tumor cells possessed a higher invasive capability than the primary NB cells. The expression of 25 metastasis-related genes was found to be significantly altered in metastatic tumors compared to primary tumors, including RECK, MMP2, VEGF, MMP3, and CXCL12. In conclusion, we successfully established a human NB xenograft model with high tumor-bearing and metastatic rates in nude mice, providing an ideal animal model for the in vivo study of NB.

Published data regarding the association between aryl hydrocarbon receptor (Ahr) rs2066853 polymorphism and the risk of breast cancer shows conflicting results. We performed a meta-analysis on 2999 patients and 3050 controls from three related case-control studies to estimate the association between Ahr rs2066853 polymorphism and the risk of breast cancer. The protocol was approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Florida (America NIH Publication No. 86-231985 Revision). According to the three eligible populations, the odds ratios (ORs), 95% confidence intervals (CIs) on the risk of breast cancer for the genotypes GA vs GG, AA vs GG, and A vs G were 1.06 (0.81-1.40), 0.96 (0.81-1.13), and 1.02 (0.85-1.22), respectively. The OR (95%CI) for GA + AA vs GG was 1.05 (0.80-1.37). Furthermore, after multi-variates adjustment, the ORs (95%CIs) were 1.05 (0.80-1.38) for GA vs GG, and 0.92 (0.76-1.10) for AA vs GG. This meta-analysis suggests that Ahr (rs2066853) polymorphism would not modify the risk of breast cancer. However, further research should be conducted to provide more evidence.

The objective of this paper was to identify hub genes and pathways associated with retinoblastoma using centrality analysis of the co-expression network and pathway-enrichment analysis. The co-expression network of retinoblastoma was constructed by weighted gene co-expression network analysis (WGCNA) based on differentially expressed (DE) genes, and clusters were obtained through the molecular complex detection (MCODE) algorithm. Degree centrality analysis of the co-expression network was performed to explore hub genes present in retinoblastoma. Pathway-enrichment analysis was performed using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Validation of hub gene expression in retinoblastoma was performed by reverse transcription-polymerase chain reaction (RT-PCR) analysis. The co-expression network based on 221 DE genes between retinoblastoma and normal controls consisted of 210 nodes and 3965 edges, and 5 clusters of the network were evaluated. By assessing the centrality analysis of the co-expression network, 21 hub genes were identified, such as SNORD115-41, RASSF2, and SNORD115-44. According to RT-PCR analysis, 16 of the 21 hub genes were differently expressed, including RASSF2 and CDCA7, and 5 were not differently expressed in retinoblastoma compared to normal controls. Pathway analysis showed that genes in 2 clusters were enriched in 3 pathways: purine metabolism, p53 signaling pathway, and melanogenesis. In this study, we successfully identified 16 hub genes and 3 pathways associated with retinoblastoma, which may be potential biomarkers for early detection and therapy for retinoblastoma.

It has been shown that microRNA-215 (miR-215) is dysregulated in several human malignancies, and this correlates with tumor progression. However, its expression and function in pancreatic cancer is still unclear. The aim of this study was to explore the effects of miR-215 on pancreatic cancer formation and progression. Using quantitative RT-PCR, we detected miR-215 expression in pancreatic cancer cell lines and primary tumor tissues. The association of miR-215 expression with clinicopathological factors and prognosis was also analyzed. We then observed the effects of miR-215 on the biological behavior of pancreatic cancer cells. Lastly, the potential regulatory function of miR-215 on ZEB2 expression was investigated. miR-215 expression levels were significantly downregulated in pancreatic cancer samples and cell lines. Decreased miR-215 expression was significantly associated with large tumor size, advanced TNM stage, lymph node metastasis, vessel invasion, and lower overall survival. Multivariate regression analysis corroborated that downregulation of miR-215 was an independent unfavorable prognostic factor. Overexpression of miR-215 inhibited pancreatic cancer cell proliferation, invasion, and migration; promoted cell apoptosis in vitro; and suppressed tumorigenicity in vivo. Further, ZEB2 was confirmed as a direct target of miR-215 by using a luciferase reporter assay. These findings indicate that miR-215 may act as a tumor suppressor in pancreatic cancer cells, and could serve as a novel therapeutic target for miR-based therapy.

We integrated all the eligible studies and investigated whether the TNF-α 308G/A polymorphism correlates with urogenital cancer risk. Tumor necrosis factor-α (TNF-α) is a risk factor for some urogenital cancers; however, in prostate and bladder cancers the results are controversial. PubMed, EMBASE, Web of Science, the Cochrane Library, the Chinese Biomedical Literature Database, and the Wanfang Database were searched for all case-control studies on the relationship between the TNF-α 308G/A polymorphism and susceptibility to urogenital cancer between January 1994 and January 2015. The pooled odds ratio with 95% confidence interval was calculated to assess the associations. A total of 504 articles were found, 39 of which involved 11,613 cases and 12,542 controls that fulfilled the inclusion criteria. Overall, the TNF-α 308G/A polymorphism was significantly associated with the risk of urogenital cancer. In the subgroup analysis for different cancer types, significant associations were found in cervical cancer and urothelial carcinoma, while our meta-analysis indicated that there were no significant associations between the TNF-α 308G/A polymorphism and prostate, bladder, or renal cancers. When stratified by ethnicity, significant associations were observed in Caucasian populations, whereas no significant associations were found in African-Americans, Asians, or mixed populations. Furthermore, carriers of the -308A allele among the hospital-based case-control group were at a high risk of urogenital cancer. Our meta-analysis showed that the TNF-α 308G/A polymorphism was significantly associated with urogenital cancer risk, particularly in the Caucasian and hospital-based populations.

This report details a study conducted to assess the role of VEGF gene polymorphisms in the prognosis of advanced non-small cell lung carcinoma (NSCLC). Samples obtained from 210 advanced NSCLC patients admitted at the Huaihe Hospital of Henan University between January 2010 and December 2011 were recruited for this study. The VEGF -2578C/A (rs699947), +936C/T (rs3025039), and -634G/C (rs2010963) genotypes were analyzed by polymerase chain reaction-restriction fragment length polymorphism. We discovered, by logistic regression analysis, that the TT genotype of VEGF +936C/T was associated with more complete response + partial response to chemotherapy, compared to the CC genotype (odds ratio (OR) = 4.78, 95% confidence interval (CI) = 1.34-25.85). We also found a correlation between the TT genotype of VEGF +936C/T and lower risk of death from all causes compared to the CC genotype (OR = 0.26, 95%CI = 0.10-0.69), using the Cox proportional hazard model (after adjusting for potential confounding factors). In conclusion, we discovered that the VEGF +936C/T gene polymorphism influences the response to chemotherapy and overall survival of NSCLC patients.

Numerous studies have evaluated the association between the X-ray repair complementing defective repair in Chinese hamster cells 3 (XRCC3) T241M polymorphism and hepatocellular carcinoma (HCC) risk. However, the results of such investigations have proved inconsistent. Therefore, we performed a meta-analysis of the association between this polymorphism and HCC risk in the Chinese population. Published literature from PubMed and China National Knowledge Infrastructure databases was retrieved, and a total of 5 case-control studies consisting of 2967 patients and 3874 controls were included in this meta-analysis, which revealed a significant association between the XRCC3 T241M polymorphism and HCC risk (TT vs MM: OR = 6.54, 95%CI = 2.14-19.99; TT vs MT: OR = 4.72, 95%CI = 2.26-9.86; dominant model: OR = 0.38, 95%CI = 0.26-0.57; recessive model: OR = 1.27, 95%CI = 0.99-1.62). In a subgroup analysis by sample size (number of subjects > 1000), similar results were obtained. Thus, XRCC3 T241M polymorphism may constitute a risk factor for HCC in the Chinese population.

The A1298C polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene has been reported to be associated with hepatocellular carcinoma (HCC), but there are conflicting results from previous studies. The present study aimed to investigate the association between this polymorphism and the risk of HCC using a meta-analysis of the published studies. Published literature from PubMed and Embase databases was systematically searched to identify relevant studies before October 2014. The Begg test was used to measure publication bias. Sensitivity analyses were performed to ensure the authenticity of the outcome. The meta-analysis results showed significant association between the MTHFR A1298C polymorphism and HCC risk (CC vs AA: OR = 0.52, 95%CI = 0.33-0.81; CC vs AC: OR = 0.50, 95%CI = 0.32-0.79; dominant model: OR = 1.94, 95%CI = 1.24-3.02; recessive model: OR = 1.00, 95%CI = 0.84-1.18). In the subgroup analysis, significant associations between the MTHFR A1298C polymorphism and HCC risk were found in Asians (CC vs AA: OR = 0.46, 95%CI = 0.27-0.78; CC vs AC: OR = 0.41, 95%CI = 0.24-0.71; dominant model: OR = 2.27, 95%CI = 1.33-3.86; recessive model: OR = 1.03, 95%CI = 0.86-1.24). Our results suggest that the MTHFR A1298C polymorphism might be related to increased risk of HCC in Asians. Further large and well-designed studies are needed to confirm these conclusions.

We investigated the clinical significance and prognostic value of microRNA-100 (miR-100) in bladder cancer. Quantitative real-time polymerase chain reaction was used to analyze the expression of miR-100 in 92 pairs of human bladder cancer and adjacent normal tissue samples. Overall survival (OS) curves were plotted using the Kaplan-Meier method and were evaluated for statistical significance using a log-rank test. The significance of different variables with respect to survival was analyzed using the multivariate Cox proportional hazard model. The miR-100 expression level was significantly lower in bladder cancer tissues than in normal adjacent tissues (mean ± SD: 1.49 ± 0.52 vs 2.79 ± 0.59, P < 0.05). A low miR-100 expression level was correlated with tumor stage (P = 0.023), tumor grade (P = 0.031), and regional lymph node involvement (P = 0.16). Kaplan-Meier analysis with log-rank test indicated that low miR-100 expression had a significant impact on OS (35.1 vs 75.3%; P = 0.004). Multivariate analysis revealed that the miR-100 expression level was an independent prognostic factor for OS (HR = 2.768, 95%CI = 1.287-8.992; P = 0.009) in bladder cancer patients. The present study demonstrated that the downregulation of miR-100 was associated with advanced clinical features and poor prognosis for bladder cancer patients, suggesting that miR-100 downregulation may be used as an unfavorable prognostic biomarker in bladder cancer.