Original article: The expression of CFL1 and N‐WASP in esophageal squamous cell carcinoma and its correlation with clinicopathological features

Cofilin1 (CFL1) is an actin‐modulating protein, which belongs to the ADF/Cofilin family. Neural Wiskott–Aldrich syndrome protein (N‐WASP) is the key regulator of the actin cytoskeleton, a member of Wiskott‐Aldrich syndrome protein family. They have been suggested to be involved in cancer cell invasion and metastasis. In this study, the expression patterns of CFL1 and N‐WASP in normal esophageal mucosa and esophageal squamous cell carcinoma (ESCC) and their correlation with clinical characteristics were investigated. Immunohistochemical staining showed that CFL1 was expressed in nuclear and cytoplasm of cancer cells. However, N‐WASP was mainly found in the cytoplasm of the cancer cells. There were significant evidences that proved that CFL1 is correlated with clinicopathological factors in ESCC, such as infiltration depth, lymph node metastasis and pathological staging (P < 0.05). It is also proved that N‐WASP is related to lymph node metastasis and pathological staging in ESCC (P < 0.05). Kaplan–Meier analysis showed that there was no correlation between CFL1 and N‐WASP protein expression and survival (P > 0.05). Moreover, the mRNA expression of CFL1 and N‐WASP was detected by quantitative real time PCR in 70 tissue specimens. The results showed that CFL1 mRNA level was over‐expressed in ESCC tissue (P < 0.05), while N‐WASP mRNA expression level was not different between cancerous tissues and adjacent normal esophageal mucosa (P > 0.05). Also, CFL1 mRNA expression was significantly associated with regional lymph node metastasis and pathological staging (P < 0.05). Kaplan–Meier analysis showed that there was no correlation between CFL1 and N‐WASP mRNA expression and survival (P > 0.05). Our findings suggested that CFL1 and N‐WASP may play an important role in the tumorigenesis of ESCC, and to be the candidate novel biomarkers for the diagnosis and prognosis of ESCC. These findings may have implications for targeted therapies in patients with ESCC.     

Clinical effect of E‐series of prostaglandin receptor 2 and epidermal growth factor receptor signal pathways in the development of esophageal squamous cell carcinoma

Signal pathways mediated by epidermal growth factor receptor (EGFR) and E‐series of prostaglandin receptors (EPs) are closely correlated to the pathogenesis of tumor. This experiment was designed to investigate the expression and clinical significance of EP2 and EGFR in esophageal squamous cell carcinoma (ESCC). Tissue samples were collected reterospectively from 87 patients with ESCC (first diagnosed). The patients were followed up for 5 years after radical surgery. The expression of EP‐2 and EGFR were examined by tissue chip technology and immunohistochemistry methods. Clinicopathological and prognostic impact were evaluated. Overexpression of EGFR and EP‐2 was more observed in ESCC than the control group (58.6% vs. 13.9%; 52.9% vs. 4.88%, P < 0.001, respectively); which correlated with tumor infiltration depth, lymph node metastasis, and tumor‐lymph node‐metastasis staging. Both the EP‐2 and EGFR overexpression were detected in 39 specimens and exhibited the positive correlation (P < 0.001, r = 0.404). Overexpression of EP2 and EGFR exhibited significant correlation with worse 5‐year overall survival than those with negative result (17.6% vs. 27.8%, P = 0.011; 10.9% vs. 34.1%, P < 0.001, respectively). Cox proportional hazard model showed that the T‐staging, lymph node metastasis, and EGFR overexpression were the independent risk factors of the prognosis. The present study exhibited that the overexpression of EP2 and EGFR in ESCC tissues might play an important role in carcinogenesis and the progression of ESCC.     

The expression of CXCR4 and its relationship with matrix metalloproteinase‐9/vascular endothelial growth factor in esophageal squamous cell cancer

Esophageal cancer (EC) is a highly aggressive neoplasm with poor prognosis. The main reason for this disappointing outcome is the strong behavior of esophageal cancer cell's invasion and metastasis. CXC chemokine receptor 4 (CXCR4) was found to be expressed in many tumors and significantly correlated with invasion, angiogenesis, metastasis, and prognosis. In the present study, we investigated the expressions of CXCR4, matrix metalloproteinase‐9 (MMP‐9), and vascular endothelial growth factor (VEGF) in esophageal squamous cell cancer (ESCC) and analyzed the relationship among the three proteins. Sections of paraffin‐embedded tissues were obtained from 127 patients with ESCC undergoing esophagectomy at Zhongshan Hospital, Fudan University in 2005. The CXCR4, MMP‐9, and VEGF expressions in EC tissues were evaluated according to the immunohistochemical staining area and intensity. The correlations between patients' prognosis and covariates were analyzed by Kaplan–Meier method (univariate analysis) and Cox regression (multivariate analysis). The overall expression rate of CXCR4, MMP‐9, and VEGF was 88.2%, 93.7%, and 79.5%, respectively. CXCR4 expression was significantly associated with tumor grade, tumor size, tumor depth, regional lymph node metastasis, and tumor, node, metastasis (TNM) stage (P < 0.05). MMP‐9 expression was significantly associated with age and tumor grade (P < 0.05). VEGF expression was significantly associated with tumor grade, tumor depth, and TNM stage (P < 0.05). CXCR4 expression was positively correlated with MMP‐9 expression (P < 0.01, r= 0.365) and VEGF expression (P < 0.01, r= 0.380). However, there was no significant correlation between MMP‐9 and VEGF expression (P > 0.05). In univariate analysis, CXCR4 expression, tumor size, tumor depth, lymph node metastasis, and TNM stage were correlated with patients' prognosis (P < 0.05); in multivariate analysis, tumor size and lymph node metastasis were the independent factors of poor prognosis. CXCR4 was highly expressed in ESCC and correlated with MMP‐9, VEGF, clinicopathological features and prognosis. We speculated CXCR4 play an important role during the progression of this disease and there might be some regulatory mechanism existing between CXCR4 and MMP‐9/VEGF in ESCC.     

Association between positive murine double minute 2 expression and clinicopathological characteristics of esophageal squamous cell carcinoma: a meta‐analysis

The correlations of murine double minute 2 (MDM2) T309G and esophageal cancer were elucidated because the association between MDM2 expression states and clinicopathological parameters of esophageal squamous cell carcinoma (ESCC) is controversial. We conducted a meta‐analysis on studies screened from PubMed, Web of Science, Embase, the Cochrane Library, and the Chinese Biomedical Literature Databases that were published before October 2014. All studies describing the association between MDM2 and ESCC were traced. Meta‐analysis was performed using the STATA software (Stata Corp., College Station, TX, USA). A total of 9 studies with 707 cases and 324 controls were included. MDM2 expression was higher in ESCC than in normal esophageal epithelium (odds ratio [OR] 10.38, 95% confidence interval [CI] 6.42–16.78, P < 0.001). High MDM2 expression was associated with early primary tumor stage (T1/T2 vs. T3/T4, OR 0.59, 95% CI 0.38–0.92, P = 0.018) and increased risk of regional lymph node metastasis (N0 vs. N1, OR 1.66, 95% CI 1.03–2.67, P = 0.039). However, no relationship was observed between MDM2 expression and the risk of distant metastasis (OR = 2.09, 95% CI 1.00–4.36, P = 0.050), and MDM2 was not significantly correlated with TP53 expression (OR 1.22, 95% CI 0.53–2.77, P = 0.643). Our analysis suggests that MDM2 acts as a potent marker of early primary tumor stage but higher risk of regional lymph node metastasis in ESCC. However, because of the limited number of studies included, the result should be further clarified by well‐designed prospective studies.     

Expression of E-cadherin, cyclin D1, matrix metalloproteinase 9, and vascular endothelial growth factor in primary tumor of esophageal squamous cell carcinoma does not predict lymph node micrometastasis

Background In esophageal squamous cell carcinoma (ESCC), it has been reported that some genes are associated with lymph node (LN) metastasis. The intent of this study was to clarify the relation between LN micrometastasis and gene expression in ESCC.Methods Micrometastasis of 2749 LN of 67 patients with thoracic ESCC were examined by cytokeratin staining. Of 67 patients, 38 were pN0 and 29 were pN1. The expression of E-cadherin, cyclin D1, matrix metalloproteinase 9 (MMP9), and vascular endothelial growth factor (VEGF) in the primary tumor was examined by immunohistochemical analysis.Results Sixteen of 38 pN0 patients had LN micrometastasis. However, there was no correlation between the expression of the four genes and LN micrometastasis (E-cadherin, P = 0.74; cyclin D1, P = 0.12; MMP9, P = 0.51; VEGF, P = 0.32). When the patients with pN1 were included in the analysis, there was also no significant association between expression of the four genes and micrometastasis.Conclusions There was no significant association between the expression of E-cadherin, cyclin D1, MMP9, VEGF, and LN micrometastasis in ESCC.     

CXCR4 heterogeneous expression in esophageal squamous cell cancer and stronger metastatic potential with CXCR4‐positive cancer cells

CXCR4 belongs to a family of G protein‐coupled cell surface receptors and has been proved to a prognostic marker in a various tumors, including esophageal squamous cell cancer. In this study, we analyzed CXCR4 expression in tumor tissue and metastatic tumor tissues of lymph node by immunohistochemistry. CXCR4 was found to be an independent factor of patients' survival and heterogeneously expressed in tumor tissues. Compared with the primary tumor tissues, the scores of CXCR4 expression were significantly higher in corresponding metastatic tumor tissues of lymph nodes (P < 0.01). It was suggested CXCR4‐positive cells were prone to migrate to lymph nodes. In the further experiments in vitro, we confirmed heterogeneous expression of CXCR4 in esophageal squamous cell cancer cell lines (KYSE70, Ec109, and CaES17) by flow cytometry analysis. Meanwhile, two subpopulations were isolated from Ec109 based on CXCR4 membrane expression by fluorescence‐activated cell sorting. CXCR4‐positive cells showed stronger migration ability in Boyden chamber assay than CXCR4 negative ones (P < 0.01). However, no significant difference of cell proliferation was found between the two subpopulations in colony formation assay (P > 0.05). We concluded that CXCR4 might be a key molecule in esophageal squamous cell cancer metastasis.     

Prognostic relevance and therapeutic implications of centromere protein F expression in patients with esophageal squamous cell carcinoma

Centromere protein F (CENP‐F), a cell cycle‐regulated centromere protein, has been shown to affect numerous tumorigenic processes. This study aimed to clarify the prognostic significance of CENP‐F expression in patients with esophageal squamous cell carcinoma (ESCC). The levels of CENP‐F messenger RNA and protein were higher in ESCC cell lines than in the normal tissues. An immunohistochemical analysis of paired tissue specimens showed that the CENP‐F expression was higher in tumorous tissues than in the adjacent non‐tumorous tissues (P < 0.001). Moreover, there was a significant correlation between CENP‐F expression and gender (P = 0.012), clinical stage (P = 0.039), and T classification (P = 0.026). Patients with higher CENP‐F expression had shorter overall survival than those with lower CENP‐F expression (P = 0.009). Multivariate Cox analysis indicated that CENP‐F expression is an independent prognostic factor for overall survival (hazard ratio = 0.582, 95% confidence interval = 0.397–0.804, P = 0.041). Importantly, it was found that zoledronic acid (ZOL) could significantly enhance the chemotherapeutic sensitivity of ESCC cell lines with high CENP‐F expression to cisplatin, although ZOL alone only exhibited a minor inhibitory effect to ESCC cells. In summary, these findings demonstrate that CENP‐F may serve as a valuable molecular marker for predicting the prognosis of ESCC patients. In addition, the data indicate a potential benefit of combining ZOL with cisplatin in ESCC, suggesting that CENP‐F expression may have therapeutic implications.     

Common single nucleotide polymorphism of hypoxia‐inducible factor‐1α and its impact on the clinicopathological features of esophageal squamous cell carcinoma

OBJECTIVE: Angiogenesis is one of the most important molecular events in solid tumor development and growth, in which hypoxia‐inducible factor (HIF)‐1α is a key regulator and plays an important role. Studies have shown that a single nucleotide polymorphism (C1772T) in the HIF‐1α gene exerts a large effect on the phenotype of human head and neck squamous cell carcinoma and renal cell carcinoma. But the impact of the C1772T polymorphism on the clinicopathological features of human esophageal squamous cell carcinoma (ESCC) remains unknown, and thus it is the main focus of our study. METHODS: The C1772T genotype of 95 ESCC patients and 104 healthy controls were studied by using the polymerase chain reaction and restriction fragment length polymorphism. Mutations were confirmed by direct DNA sequencing. The impact of C1772T on tumor size, invasive depth, lymph node metastasis, distant metastasis, histological grade and TNM stage was also studied. RESULTS: The genotype frequency observed in the patients and controls was 11.58% versus 10.58%, respectively, for genotype C/T (P > 0.05). Genotype T/T was not found in our study. Larger tumors and a higher rate of lymph node metastasis was found for the C/T group. CONCLUSIONS: Although there is no significant difference of genotype distribution between ESCC patients and healthy controls, genotype C/T is associated with larger tumor and higher rate of lymph node metastasis.     

Protein kinase D1 mRNA level may predict cancer‐specific survival in heavy smokers with esophageal squamous cell cancers

Protein kinase D1 (PRKD1) is a kinase that regulates various pathways, which involve in cell proliferation, apoptosis, cell adhesion and invasion. Although PRKD1 expression has been observed in many cancers, its role in esophageal squamous cell cancer (ESCC) has not been well reported. As its dysregulation in cancers is organ specific, we sought to investigate the potential role of PRKD1 in the progression of ESCC. Samples were collected from 178 patients with completely resected ESCCs at Sun Yat‐sen University Cancer Center, including 47 pairs of tumorous and non‐tumorous tissues. PRKD1 mRNA expression was investigated by quantitative real‐time polymerase chain reaction. Receiver operating characteristic (ROC) curve analysis was used to search for a feasible cut‐off point of PRKD1 mRNA levels for predicting cancer‐specific survival. Kaplan–Meier and multivariate Cox regression analysis were used to assess the prognostic value of PRKD1 mRNA level in ESCC patients. In result, upregulation of PRKD1 mRNA was detected in 55.3% (26/47) of ESCC tissues compared with paired non‐tumorous ones (P = 0.011). ROC analysis indicated 3.28 as a cut‐off point, and thus 72 and 106 tumors with low and high PRKD1 mRNA expression were categorized. High‐PRKD1 mRNA expression in tumors appeared with more frequency in heavy smokers (P = 0.002) and patients with advanced pathological T category (P = 0.034). Kaplan–Meier analysis indicated that patients with low‐PRKD1 mRNA had a longer cancer‐specific survival than the ones with high‐PRKD1 level (P = 0.044). Multivariate analysis showed that tumorous PRKD1 mRNA expression was an independent prognostic factor (hazard ratio: 1.538, 95% confidence interval: 1.018–2.323, P = 0.041) in resected ESCC. Subgroup analysis revealed that the discernibility of PRKD1 mRNA level on ESCC outcomes was only pronounced in heavy smokers (P = 0.002), but not in non‐heavy smokers (P = 0.870). PRKD1 might play a potential oncogenic role in ESCC. It might be an independent biomarker to predict prognosis in heavy smokers with ESCC.     

Amplification of the telomerase RNA component gene as a new genetic marker for disease progression and prognosis in esophageal squamous cell carcinoma

Amplification of the human telomerase RNA component (TERC) gene was found in esophageal squamous cell carcinoma (ESCC). However, its roles in the progression and prognosis of ESCC have not been well understood. The amplification of TERC in normal mucosa, low‐grade and high‐grade intraepithelial neoplasia, and invasive ESCC samples were evaluated using a fluorescence in situ hybridization assay. The amplification of TERC invariably occurred in high‐grade intraepithelial neoplasia and invasive ESCC, partially occurred in low‐grade intraepithelial neoplasia specimens, and seldom occurred in normal mucosa. The average signal ratio of TERC to chromosome 3 centromere‐specific probe (TERC/CSP3) was 1.00 ± 0.01 (average ± standard deviation) in normal mucosas, 1.01 ± 0.08 in low‐grade intraepithelial neoplasias, 1.39 ± 0.26 in high‐grade intraepithelial neoplasias, and 1.56 ± 0.41 in invasive ESCC. High TERC/CSP3 ratio was positively associated with lymph node metastasis (P = 0.005) and advanced tumor stage (P = 0.045). Patients with high amplification of TERC had poor survival (P = 0.01). The amplification of TERC could be used as a new genomic marker for disease progression and prognosis of ESCC. The amplified TERC gene may be a potential therapeutic target for ESCC.     

Expression of urokinase-type plasminogen activator receptor and plasminogen activator inhibitor-1 in gastric cancer

In gastric cancer, the urokinase-type plasminogen activator (uPA) system plays important roles in invasion and metastasis, processes which entail proteolysis and adhesion. Both the urokinasetype plasminogen activator receptor (uPAR) and the plasminogen activator inhibitor-1 (PAI-1) are thought to be important factors in this system. To clarify the relationship between these two factors and gastric cancer invasiveness, we evaluated the expression of uPAR and PAI-1 in 91 cases of gastric cancer by immunohistochemistry and in situ hybridization. Urokinase-type plasminogen activator receptor-mRNA, PAI-1-mRNA, uPAR and PAI-1 protein were diffusely distributed in the cytoplasm of the cancer cells and concentrated at invasive foci. Urokinase-type plasminogen activator receptor protein expression correlated with lymphatic, venous invasion (P<.01) and lymph node metastasis (P<0.05); uPAR-mRNA expression correlated with lymphatic, venous invasion and lymph node metastasis (P<0.05). Plasminogen activator inhibitor-1 protein expression correlated with lymphatic, venous invasion, lymph node metastasis and depth of invasion (P<0.01); PAI-1-mRNA expression was linked to lymphatic, venous invasion (P<0.01), lymph node metastasis and depth of invasion (P<0.05). This suggests that the proteolytic activity of uPAR and the cellular motility of PAI-1 in gastric cancer cells may determine penetration of lymphatic and blood vessels, whereby lymph node metastasis may be promoted and that the promotion of cellular motility by PAI-1 may influence the depth of cancer invasion.     

PTEN hypermethylation profiles of Chinese Kazakh patients with esophageal squamous cell carcinoma

Aberrant DNA methylation of promoter region CpG islands may serve as an alternative mechanism to genetic defects in the inactivation of tumor suppressor genes (TSGs) in human malignancies. The aim of this study was to examine the promoter methylation status of the PTEN TSG and its association with esophageal squamous cell carcinoma (ESCC) carcinogenesis in a Chinese Kazakh population, which is known to have a relatively high ESCC incidence and mortality. The methylation status of the PTEN promoter region was determined in patients with ESCC (n = 95) and healthy individuals (n = 65) using highly sensitive Sequenom Epityper assays. The methylation level of the PTEN gene was significantly higher in patients with ESCC than in healthy controls. The median methylation level was 10.0% (interquartile range [IQR]: 7.0–11.0%) in patients with ESCC and 6.0% in controls (IQR: 4.0–9.0%; P = 0.001). PTEN methylation levels were higher in male patients with ESCC than in male controls, whereas a trend toward significance was observed between female patients with ESCC and female controls (P = 0.005 and P = 0.086, respectively). The PTEN methylation level was associated with histopathological grade and lymph node metastasis in patients with ESCC (P = 0.002 and P = 0.009, respectively). To our knowledge, this is the first report to show the presence of PTEN promoter CpG hypermethylation in ESCC and its association with tumor metastasis.     

Expression of klotho and β‐catenin in esophageal squamous cell carcinoma,and their clinicopathological and prognostic significance

Esophageal carcinoma is one of the most common types of cancers in the world; the molecular mechanism underlying its tumorigenesis is still not well understood. This study was aimed at investigating the expression of klotho and β‐catenin in patients with esophageal squamous cell carcinoma (ESCC) and analyzing their association with clinicopathological variables and their effects on prognosis. The expression patterns of klotho and β‐catenin were determined by tissue microarray and immunohistochemical technique in ESCC and normal tissues, and their correlations with clinicopathological characteristics were investigated using univariate and multivariate analysis. The serum klotho levels in 40 ESCC patients and controls were measured by sandwich enzyme‐linked immunosorbent assay system (ELISA). The expression level of klotho was significantly lower in ESCC than in the adjacent noncancerous tissues (30 vs. 50%, P < 0.000), and the protein level was negative correlated with clinical staging, histological grade, lymph node metastasis, and invasion depth (P < 0.05). Whereas, the expression of β‐catenin was much higher in ESCC than their corresponding normal mucosa tissues (78.3 vs. 11.5%, P < 0.000), and the level of protein correlated only with histological grade and invasion depth (P < 0.05). Correlation analysis showed the expression level of klotho inversely correlated with that of β‐catenin (r = ?0.214, P < 0.01). Patients with klotho‐positive tumors had longer survival than those with klotho‐negative tumors (P < 0.01). Cox proportional hazards model analysis demonstrated that positive expression of klotho was an important factor indicating good prognosis (hazard ratio, 0.371; 95% confidence interval, 0.201–0.685; P < 0.01). ELISA showed that the level of serum klotho was markedly higher (461.50 ± 43.30 pg/mL) than control group (239.37 ± 20.65 pg/mL) (P < 0.001). Receiver operating characteristic analysis gave a cut‐off value of 327.031 of serum klotho with a sensitivity of 81.3% and specificity of 81.2% (P < 0.000). Our present study demonstrated for the first time that klotho might be a novel biomarker candidate for predicting progression and prognosis in patients with ESCC.     

Original article: Upregulation of caspase‐3 expression in esophageal cancer correlates with favorable prognosis: an immunohistochemical study from a high incidence area in northern China

Caspase‐3 plays an important role as the key effector during apoptosis, but there are very few studies of caspase‐3 in esophageal squamous cell carcinoma (ESCC). The purpose of this study was to investigate the expression and prognostic significance of caspase‐3 in ESCC from Linzhou City, a high incidence area in northern China. All 64 patients underwent esophagectomy for ESCC between January 2002 and December were enrolled in this study. Caspase‐3 expression was assessed by immunohistochemistry (IHC) in primary ESCC and paired normal esophageal epithelium. The positive rate of caspase‐3 expression was higher in ESCC than in normal esophageal epithelium (79.7% vs. 50.0%, Chi‐square = 12.372, P= 0.001). Caspase‐3 expression was correlated with tumor cell differentiation (Phi = 0.717, P < 0.001), tumor infiltration depth (Phi =?0.334, P= 0.008), and pathologic TNM (pTNM) staging (rs =?0.268, P= 0.032). Patients in caspase‐3 positive group had a significantly better 5‐year overall survival than those in the negative group (77.4% vs. 35.9%, χ²= 7.344, P= 0.007). Our results showed that caspase‐3 expression was upregulated in ESCC compared with normal esophageal epithelium in population of Chinese high incidence area, and patients with caspase‐3 positive expression had better prognosis. Therefore, caspase‐3 immunostaining could be a simple and useful tool for predicting survival in ESCC patients.     

Effects of DNA methyltransferase 1 inhibition on esophageal squamous cell carcinoma

To explore the role of DNA methyltransferase 1 (DNMT1) in esophageal squamous cell carcinoma (ESCC) and the potential of DNMT1‐targeted small interfering RNA as ESCC therapy, we examined expression changes of DNMT1 in ESCC and investigated the effect of DNMT1 knockdown by RNA interference in a human ESCC cell line, KYSE30. DNMT1 messenger RNA was over‐expressed in seven out of 12 ESCC samples, and the percentage of cells expressing DNMT1 was significantly higher in ESCC tissues compared with paired non‐cancerous tissues. DNMT1 protein levels correlated with lymph node metastasis, but exhibited no correlation with sex, age, tumor site, or tumor differentiation. Knockdown of DNMT1 in KYSE30 cells using RNA interference resulted in a reduction of promoter methylation and re‐expression of methyl‐guanine methyl‐transferase and retinoic acid receptors beta, inhibition of cell proliferation/viability and induction of cell apoptosis. These results indicate that DNMT1 over‐expression is involved in ESCC and correlated with lymph node metastasis. Knockdown of DNMT1 led to promoter demethylation and re‐expression of several tumor suppressor genes thereby inhibiting cell proliferation/viability and inducing cell apoptosis.     

Human papillomavirus type 16 infection may be involved in esophageal squamous cell carcinoma carcinogenesis in Chinese Kazakh patients

The aim of this study was to investigate human papillomavirus type 16 (HPV16) prevalence in esophageal squamous cell carcinoma (ESCC) in Xinjiang Kazakh patients and its role in ESCC carcinogenesis. One hundred and fifty cases of ESCC and 150 cases of corresponding normal esophageal mucosa (CNGM) samples were collected from north Xinjiang where the Kazakh ethnic group has lived since ancient times. HPV16 infection in ESCC and CNGM was detected by genotype‐specific polymerase chain reaction. HPV16 DNA was detected in 55 of 150 ESCC samples (36.7%) and 24 of 150 corresponding normal esophageal mucosa samples (16%) with significant differences (P < 0.001, odds ratio = 3.039, 95% confidence interval: 1.756–5.260). No statistically significant correlations were found between HPV16 infection and the age or gender of patients, tumor site, tumor cell differentiation, or lymph node metastasis (P > 0.05). HPV16 infection is common in cases of ESCC in the Kazakh ethnic group in Xinjiang and may be involved in ESCC carcinogenesis.     

Relationship between altered expression levels of MIR21, MIR143, MIR145, and MIR205 and clinicopathologic features of esophageal squamous cell carcinoma

In spite of the undisputed importance of altered expression patterns of microRNAs (miRNAs) in various cancers, there is little information on the clinicopathologic significance of cancer‐related miRNAs (MIR21, MIR143, MIR144, MIR145, and MIR205) in esophageal squamous cell carcinoma (ESCC). We examined the expression levels of the precursor and mature miRNA genes in ESCC using real‐time polymerase chain reaction (PCR). We also investigated the mRNA expression levels of processing elements (RNASEN, DGCR8, and DICER1) that participate in miRNA‐biogenesis pathway. Furthermore, we analyzed the relationships between the expression levels of these five miRNAs and the clinicopathologic parameters of ESCC patients. The expression levels of mature MIR21 and mature MIR145 were higher in ESCC than those in normal epithelium (P < 0.05). The mature/pre ratio of MIR21 in ESCC was higher than that in normal epithelium (P < 0.05). With regard to miRNA‐processing elements, the expression level of RNASEN was higher in ESCC than in normal epithelium (P < 0.05). Furthermore, altered expression of these miRNAs was related to the clinicopathologic features of ESCC patients. The high expression of mature MIR21 and mature MIR205 was associated with lymph node positivity in ESCC patients (P < 0.05). The high levels of expression of mature MIR143 and mature MIR145 were associated with recurrence of metastasis in ESCC patients (P < 0.05). The findings may imply that miRNA biogenesis is aberrantly accelerated in ESCC. Analysis of the expression levels of miRNAs should provide useful information for evaluation of the staging, prognosis, and treatment of ESCC patients.