Background:TLR4/NF-κB signaling pathway is involved in the tumorigenesis of a variety of malignancies via multiple mechanisms. However,its role in gastric cancer is not clearly clarified yet. Aims:To investigate the expressions of molecules in TLR4/NF-κB signaling pathway and their correlations with the clinicopathological characteristics of gastric cancer. Methods:A total of 154 endoscopic or surgical specimens of gastric cancer were collected at the Xijing Hospital of Digestive Diseases,the Fourth Military Medical University from Jan. 2014 to Oct. 2016 and were categorized into Helicobacter pylori(Hp)-positive group and Hp-negative group according to the status of Hp infection. Expressions of TLR4,MyD88 and NF-κB mRNA in gastric cancer tissues were detected by real-time PCR. Results:In Hp-positive group,expression levels of TLR4,MyD88 and NF-κB mRNA in gastric cancer tissues were significantly higher than those in Hp-negative group(P <0.05). Furthermore,it was found that the expression levels of TLR4,MyD88 and NF-κB mRNA in patients with poorly differentiated or undifferentiated cancer,with distant metastasis and in TNM stageⅢ-Ⅳwere significantly higher than those in patients with well-to-moderately differentiated cancer,without distant metastasis and in TNM stage Ⅰ-Ⅱ,respectively(P all <0.05). Spearman correlation coefficient analysis revealed that the expression levels of TLR4,MyD88 and NF-κB mRNA were positively correlated with each other in gastric cancer tissues(r=0.734 for TLR4 and MyD88,r =0. 657 for TLR4 and NF-κB,and r = 0. 828 for MyD88 and NF-κB,P all < 0. 05). Conclusions:TLR4/NF-κB signaling pathway is implicated in the tumorigenesis of Hp infection-related gastric cancer. In gastric cancer tissues,TLR4/NF-κB signaling pathway might be associated with the malignant behavior of tumor and promote tumor progression.

Objective:To explore the optimization strategy of the Asia-Pacific colorectal screening (APCS) scoring system in the screening of colorectal neoplasms.Methods:From February to Decomber in 2016 and March to December in 2018, at Xijing Hospital of Air Force Military Medical University and the First Affiliated Hospital of Xi′an Medical University, patients who received opportunistic screening colonoscopy were enrolled. Before colonoscopy, the APCS score (low-risk zero to one points, medium-risk two to three points and high-risk four to seven points), body mass index (BMI), fecal occult blood test (FOBT) and plasma methylated Septin9 gene ( mSEPT9) of all patients were detected and recorded. The results of colonoscopy and biopsy pathology were taken as the gold standard, the efficacies of the above methods in screening colorectal neoplasms were compared to determine and optimize the screening efficiency of APCS scoring system. Chi-square test was used for statistical analysis. Results:A total of 494 patients were screened, of whom 133 cases were diagnosed with colorectal polyps, including 86 cases of colorectal adenomatous polyps (82 cases of non-progressive adenoma, and four cases of advanced-adenoma), and 47 cases of non-adenomatous polyps. According to the APCS score, the detection rate of colorectal adenomatous polyps of the high-risk group (33.3%, 33/99) was 2.02 and 3.76 times higher than those of the medium-risk group (16.5%, 39/237) and low-risk group (8.9%, 14/158), respectively (both Bonferroni correction test, both P<0.016). The detection rate of colorectal adenomatous polyps of patients with BMI>23.9 kg/m 2 was significantly higher than that of patients with BMI≤23.9 kg/m 2 (22.2%, 59/266 vs. 11.8%, 27/228), and the difference was statistically significant ( χ2=9.126, P=0.003). There was no statistically significant difference in the detection rate of colorectal adenomatous polyps between patients with positive- mSEPT9 expression and patients with negative- mSEPT9 expression (22.4%, 15/67 vs. 17.3%, 47/271) ( χ2=0.913, P=0.378). Among 158 low and medium risk patients (APCS score≤three points) who underwent simultaneous BMI measurement, FOBT and plasma mSEPT9 test, the detection rate of colorectal adenomatous polyps in patients with BMI>23.9 kg/m 2 was higher than that in patients with BMI≤23.9 kg/m 2 (17.8%, 16/90 vs. 5.9%, 4/68), and the difference was statistically significant ( χ2=4.957, P=0.030). The redetection efficacy of colorectal adenomatous polyps in patients with BMI>23.9 kg/m 2 and FOBT-positive was higher than that in patients with BMI≤23.9 kg/m 2 and FOBT-negative (28.1%, 9/32 vs. 8.0%, 4/50) and the difference was statistically significant ( χ2=5.942, P=0.027). In addition, the redetection rate of colorectal adenomatous polyps of patients with positive expression of FOBT and plasma mSEPT9 was also higher than that of patients with negative expression (5/14 vs. 12.9%, 12/93), and the difference was statistically significant ( χ2=4.738, P=0.045). Conclusions:When the APCS scoring system is used for sequential screening of colorectal tumors, the optinal choice of BMI replacement or combined with FOBT can improve the patients′ compliance and screening efficiency, which has significant clinical significance and promotion value in the early diagnosis and treatment of colorectal neoplasms.

Objective:To investigate the relationship between the expression of DNA methyltransferase 3b (DNMT3b) and the methylation of SEPT9 gene, and their application prospects in the diagnosis and treatment of colorectal cancer.Methods:Seventy-five cases of colorectal cancer and adjacent tissues, 68 cases of colorectal high-grade internal neoplasia tissues (referred to as precancerous tissues) and high-grade internal adjacent neoplasia tissues (referred to as adjacent precancerous tissues) were collected. Pyrosequencing was used to detect the methylationlevel of SETP9. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to examine the mRNA expressionof SEPT9 and immunohistochemistry(IHC) was applied to detect the protein expressions of SETP9 and DNMT3b. Liposome-mediated method was used to transfect DNMT3b siRNA and negative control siRNA into HT-29 cells. Five groups including DNMT3b siRNA 15 nmol/L group, DNMT3b siRNA 30 nmol/L group, negative control siRNA 15 nmol/L group, negative control siRNA 30 nmol/L group and blank control group were set up. Pyrosequencing was applied to determine the methylation level of SEPT9 and mRNA expression of DNMT3b in each group.Results:The methylation rates of SEPT9 gene in colorectal cancer tissues, adjacent tissues, precancerous tissues and adjacent precancerous tissues were (76.8±6.5)%, (14.4±2.6)%, (34.6±5.0)% and (7.4±1.2)%, respectively, which was highest in colorectal cancer tissue ( P<0.001). The relative expressions of SEPT9 mRNA were 0.18±0.03, 0.89±0.41, 0.69±0.41 and 1.01±0.21, respectively, which was lowest in colorectal cancer tissue ( P<0.001), while there were no statistically significant differences in adjacent tissues, precancerous tissues and adjacent precancerous tissues ( P>0.05). The positive rates of SEPT9 protein expression were 12.0% (9/75), 53.3% (40/75), 55.1% (38/69) and 62.3% (43/69), which was lowest in the colorectal cancer tissue ( P<0.001), while there were no statistically significant differences in the adjacent group, precancerous group and adjacent precancerous group ( P>0.016 7). The positive rates of DNMT3b protein expression were 56.3% (45/75), 26.7% (20/75), 46.4% (32/69) and 33.3% (23/69), respectively, which was highest in colorectal cancer tissue ( P<0.001), while without statistically significant difference from the precancerous tissue ( P>0.016 7). Experiments in vitro showed that DNMT3b mRNA expression was lowest in DNMT3b siRNA 30 nmol/L group among five groups and was statistically different from other groups (all P<0.05). Meanwhile, the methylationrate of SEPT9 gene was lowest in this group, but without statistically significant difference from the DNMT3b siRNA 15 nmol/L group ( P>0.05). Conclusions:The expression of DNMT3b is significantly correlated with the methylation level of SEPT9 gene in different stages of colorectal cancer. The high expression of DNMT3b may be an important molecular event before SEPT9 gene methylation and it may have an important potential application value in the diagnosis and treatment of early colorectal cancer.

Objective:To investigate the relationship between the expression of DNA methyltransferase 3b (DNMT3b) and the methylation of SEPT9 gene, and their application prospects in the diagnosis and treatment of colorectal cancer.Methods:Seventy-five cases of colorectal cancer and adjacent tissues, 68 cases of colorectal high-grade internal neoplasia tissues (referred to as precancerous tissues) and high-grade internal adjacent neoplasia tissues (referred to as adjacent precancerous tissues) were collected. Pyrosequencing was used to detect the methylationlevel of SETP9. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to examine the mRNA expressionof SEPT9 and immunohistochemistry(IHC) was applied to detect the protein expressions of SETP9 and DNMT3b. Liposome-mediated method was used to transfect DNMT3b siRNA and negative control siRNA into HT-29 cells. Five groups including DNMT3b siRNA 15 nmol/L group, DNMT3b siRNA 30 nmol/L group, negative control siRNA 15 nmol/L group, negative control siRNA 30 nmol/L group and blank control group were set up. Pyrosequencing was applied to determine the methylation level of SEPT9 and mRNA expression of DNMT3b in each group.Results:The methylation rates of SEPT9 gene in colorectal cancer tissues, adjacent tissues, precancerous tissues and adjacent precancerous tissues were (76.8±6.5)%, (14.4±2.6)%, (34.6±5.0)% and (7.4±1.2)%, respectively, which was highest in colorectal cancer tissue ( P<0.001). The relative expressions of SEPT9 mRNA were 0.18±0.03, 0.89±0.41, 0.69±0.41 and 1.01±0.21, respectively, which was lowest in colorectal cancer tissue ( P<0.001), while there were no statistically significant differences in adjacent tissues, precancerous tissues and adjacent precancerous tissues ( P>0.05). The positive rates of SEPT9 protein expression were 12.0% (9/75), 53.3% (40/75), 55.1% (38/69) and 62.3% (43/69), which was lowest in the colorectal cancer tissue ( P<0.001), while there were no statistically significant differences in the adjacent group, precancerous group and adjacent precancerous group ( P>0.016 7). The positive rates of DNMT3b protein expression were 56.3% (45/75), 26.7% (20/75), 46.4% (32/69) and 33.3% (23/69), respectively, which was highest in colorectal cancer tissue ( P<0.001), while without statistically significant difference from the precancerous tissue ( P>0.016 7). Experiments in vitro showed that DNMT3b mRNA expression was lowest in DNMT3b siRNA 30 nmol/L group among five groups and was statistically different from other groups (all P<0.05). Meanwhile, the methylationrate of SEPT9 gene was lowest in this group, but without statistically significant difference from the DNMT3b siRNA 15 nmol/L group ( P>0.05). Conclusions:The expression of DNMT3b is significantly correlated with the methylation level of SEPT9 gene in different stages of colorectal cancer. The high expression of DNMT3b may be an important molecular event before SEPT9 gene methylation and it may have an important potential application value in the diagnosis and treatment of early colorectal cancer.

Objective: To explore the expression and clinical significance of plasma methylated Septin9 gene (mSEPT9) in patients with gastric cancer. Methods: From March to October in 2018, 380 patients visited Xijing Hospital of Digestive Diseases were selected. The patients were divided into gastric cancer (GC) group, atrophic gastritis (AG) group and non-atrophic gastritis (NAG) group. The positive expression rate of plasma circulating mSEPT9 of the three groups were detected by polymerase chain reaction (PCR) fluorescence probe method, its correlation with clinicopathological characteristics of gastric cancer were analyzed and also compared with the positive rate of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9). Chi-square test and continuity correction chi-square test were performed for statistical analysis. Results: The actual number of valid samples was 357 including 147 of GC group, 83 of AG group and 127 of NAG group. The positive rate of plasma mSEPT9 of GC group was higher than those of AG group and NAG group (46.9%, 69/147 vs. 4.8%, 4/83 and 3.9%, 5/127), and the differences were statistically significant (χ²=43.438 and 63.912, both P<0.016). The sensitivity and specificity of plasma mSEPT9 in patients with gastric cancers were 46.9%(69/147) and 95.7%(201/210), respectively. The positive rate of mSEPT9 was higher in gastric cancer patients with tumor maximum diameter over 5.0 cm, intestinal-type gastric cancer in Lauren classification, lymphatic metastasis, vascular and neurological invasion, middle-late stage (stage Ⅲ and Ⅳ) in clinical classification, which were 57.6% (38/66) vs. 35.6% (26/73), 52.6%(51/97) vs. 31.0% (13/42), 53.0% (61/115) vs. 25.0% (8/32), 55.6% (65/117) vs. 13.3% (4/30), 50.8% (65/128) vs. 4/19 and 53.5% (61/114) vs. 24.2% (8/33), respectively; and the differences were statistically significant (χ²=6.728, 5.517, 7.905, 17.091, 5.871 and 8.998, all P<0.05). The positive rate of plasma mSEPT9 in gastric cancer patients was higher than those of CEA and CA19-9 (46.9%, 69/147 vs. 32.0%, 47/147 and 17.7%, 26/147, respectively), and the differences were statistically significant (χ²=6.892 and 17.437, both P<0.016). Conclusions The positive expression of plasma mSEPT9 in gastric cancer patients has not only high sensitivity but good specificity as well, and it is also related to the clinical stage. The detection of this gene may have important clinical significance in non-invasive diagnosis and prognosis evaluation in patients with advanced gastric cancer.