Alteration and significance of protein expression profile in gastric cancer with preoperative conformal radiation therapy

AIM: To investigate the alteration and significance of the protein expression profile in gastric cancer with preoperative conformal radiation therapy. METHODS: The pathologically-diagnosed gastric cancer patients were randomly chosen to perform conformal radiation therapy before operation. The patients without conformal radiation treatment served as controls. The tumor tissues were collected after operation from the patients. The alteration of the protein expression profile was detected by 2-dimensional electrophoresis and MALDI-TOF-MS. The expression of vascular endothelial growth factor (VEGF), c-erbB-2 and epidermal growth factor receptor (EGFR) was detected by RT-PCR and Western blotting. RESULTS: Compared with the patients without conformal radiation therapy, the protein expression profile of tumor tissues from gastric cancer patients with conformal radiation therapy was obviously altered. The expression of VEGF, c-erbB-2 and EGFR was differentially reduced (P<0.01). CONCLUSION: The preoperative accurate conformal radiation therapy reduces the expression of gastric cancer-related epithelial proteins, indicating new therapeutic targets for gastric cancer.     

Expression and prognostic significance of SLP-2 in gastric cancer

AIM: To investigate the expression of the red cell membrane integration protein SLP-2 (stomatin-like protein 2) in gastric cancer tissues and to analyze its correlation with clinicopathological manifestations and prognosis. METHODS: One hundred and ninety gastric cancer tissue samples with detailed clinical information were collected from the Department of Pathology, Sun Yat-sen University Cancer Center. The protein expression of SLP-2 in ganstric cancer was detected by the method of immunohistochemistry. The relationships between SLP-2 expression and the clinicopathological manifestations were evaluated. RESULTS: The positive rate of SLP-2 in gastric cancer tissue was 63.2% (120/190). SLP-2 expression was relevant to infiltration depth, TNM stage and lymph node metastasis (P<0.05). However, no statistical difference was observed in the SLP-2 expression associated with sex, age, differentiation, tumor size and distant metastases. Kaplan-Meier survival curves revealed that increased expression of SLP-2 was associated with poor prognosis in gastric adenocarcinoma patients (P<0.01). Based on the univariate analysis, 7 factors were found to have statistical significance of associations with overall survival, including SLP-2 expression, lymph node metastasis, histological grade, tumor size, invasive depth, distant metastases and the 7th edition of the UICC TNM classification. Only the tumor size and the 7th edition of the UICC TNM classification were independent prognostic factors for overall survival in the multivariate analysis. CONCLUSION: SLP-2 is highly expressed in gastric adenocarcinoma tissues and may play an important role in tumor progression and metastasis. Although SLP-2 is not an independent prognostic factor, it may influence the prognosis of gastric cancer. Increased expression of SLP-2 can be used for predicting unfavorable prognosis in gastric adenocarcinoma patients.     

Identification of UCHL1 as a potential biomarker for human gastric adenocarcinoma by subcellular proteomics

AIM: To search the biomarker for illustrating the pathogenesis of human gastric adenocarcinoma by differential proteome analysis of the cytosol of human gastric adenocarcinoma cell line SGC7901 and the corresponding immortalized normal gastric gland cell line GES. METHODS: The differential expression of cytosol protein between SGC7901 and GES cells was identified with subcellular protein separation and two-dimensional SDS-PAGE combined with MALDI-TOF-MS. The differential proteins were confirmed by Western blotting and semi-quantity RT-PCR. RESULTS: Ten repeatable differential proteins were identified. Compared with the expression level in normal gastric cell line GES, ubiquitin carboxyl-terminal hydrolase L1(UCHL1) was obviously down-regulated one both at protein and mRNA levels in gastric adenocarcinoma cell lines of SGC7901, AGS, BGC823 and MKN45. The expression of UCHL1 was also far lower in gastric cancer tissues than that in the corresponding normal tissues. CONCLUSION: Our finding suggests that UCHL1 has potential value as a biomarker for the diagnosis of gastric adenocarcinoma.     

Identification of specific serum biomarkers in gastric adenocarcinoma patients

AIM: To screen the possible serum biomarkers for the diagnosis of gastric adenocarcinoma. METHODS: The surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS) was used to screen the serum samples from 109 cases of gastric adenocarcinoma and 106 control subjects (60 healthy subjects, 30 patients with chronic superficial gastritis and 16 cases of chronic atrophic gastritis). The differentially-expressed protein peaks were selected and isolated with high-performance liquid chromatography (HPLC), and processed with enzyme before liquid chromatography-mass spectrometry tandem mass spectrometry (LC-MS/MS) analysis. The data mining was performed with software Xcalibur program component Bioworks 3.2. RESULTS: Three differentially-expressed protein peaks were selected as potential serum biomarkers of gastric adenocarcinoma patients.The m/z peak at 5 906.5 showed the increase (8.53±4.33 in cancer group, and 0.88±0.31 in control group). The m/z peaks at 6 635.7 and 8 716.3 showed the decrease (6.54±2.44 and 0.93 ± 0.29, respectively, in cancer group and 17.56±4.43 and 2.16±0.98, respectively, in control group, P<0.01). The 3 m/z peaks were identified as fibrinogen α-chain, apolipoprotein A-II and apolipoprotein CI,respectively. The combined use of the 3 biomarkers distinguished the samples in the cancer patients out of the controls at a sensitivity of 93.85% (61/65) and a specificity of 94.34% (50/53). CONCLUSION: The fibrinogen α-chain, apolipoprotein A-II and apolipoprotein CI identified as potential markers for gastric adenocarcinoma show diagnostic values in clinical application.     

Effect of annexin A2 on proliferation,migration and apoptosis of human cervical cancer HeLa cells

AIM：To explore the effect of annexin A2 (ANXA2) on the proliferation, migration and apoptosis abilities of human cervical cancer HeLa cells. METHODS：Overexpression vectors and siRNA of ANXA2 were constructed, and then transfected into HeLa cells. The HeLa cells were divided into 4 groups:control group, scramble group, ANXA2 overexpression group and ANXA2-siRNA group. The expression of ANXA2 at mRNA and protein levels was examined by real-time PCR and Western blotting. MTT assay, Boyden chamber and flow cytometry were used to determine the effect of ANXA2 on the proliferation, migration and apoptosis abilities of the HeLa cells. RESULTS：The proliferation and migration of HeLa cells were obviously promoted by ANXA2 overexpression. The proliferation and migration of HeLa cells were remarkably inhibited by the transfection of ANXA2-siRNA. ANXA2 had no effect on apoptosis of HeLa cells. CONCLUSION:Silencing of ANXA2 effectively inhibits the proliferation and migration of cervical cancer cells, but has little effect on apoptosis. ANXA2 may play a pivotal role in the occurrence and development of cervical cancer, and may be used as a molecular target for the treatment of cervical cancer.     

Gastrin promotes the migration and invasion of gastric cancer cells

AIM：To study the effects of gastrin on the migration and invasion of gastric cancer cells in vitro. METHODS：The migration and invasion of gastric cancer AGS and SGC-7901 cells after treated with gastrin at concentrations of 10 nmol/L and 100 nmol/L were studied by wound-healing assay and Transwell migration and invasion assay. The cell proliferation was analyzed by MTT colorimetric method. The concentration of matrix metalloproteinase 2 (MMP-2) in the culture medium was detected by ELISA. The AGS and SGC-7901 cells without treating with gastrin served as control cells. RESULTS：Compared with the control cells, the migration and invasion of AGS cells and SGC-7901 cells were significantly increased after treated with gastrin at concentrations of 10 nmol/L and 100 nmol/L. In control, 10 nmol/L gastrin and 100 nmol/L gastrin groups, the mean numbers of the migrating cells were 56.0, 88.1 and 106.4/view in AGS cells and 52.8, 91.0 and 113.3/view in SGC-7901 cells, and the mean numbers of the invasive cells were 78.4, 118.7 and 141.6/view in AGS cells and 87.3, 124.6 and 147.4/view in SGC-7901 cells, respectively. The numbers of the migrating cells and invasive cells in 100 nmol/L gastrin group were higher than those in 10 nmol/L gastrin group. The cell proliferation rate and the concentration of MMP-2 in the culture medium in gastrin treatment groups were higher than those in control group. CONCLUSION：Gastrin promotes the migration and invasion of gastric cancer cells in a dose-dependent manner by increasing the MMP-2 secretion, which may be the key mechanism in the proliferation, invasion and metastasis of the cancer cells in vivo.     

Significance and alterations of p14ARF gene of CDKN2A locus in gastric cancer

AIM:To investigate the significance and changes of p14^ARF gene in gastric cancer.METHODS:The tumors and gastric tissues neighboring carcinoma from 48 patients with gastric cancer were studied. The homozygous deletions, mutations, methylation of the CpG islands, and mRNA expression of p14^ARF gene were assessed by PCR, PCR-SSCP, PCR based methylation assay, and RT-PCR.RESULTS:①The homozygous deletion rate of p14^ARF was 31.3% (15/48), and no homozygous deletions were examined in all the gastric tissues neighboring tumor. ②There were no point mutations of p14^ARF in 33 gastric cancers without homozygous deletion and in the matched gastric tissues adjacent to tumor. ③Methylation rate of the CpG islands of p14^ARF was significantly higher in gastric cancers(47.9%, 23/48) than that in gastric tissues neighboring cancer (4.2%, 2/48)(P＜0.01).④ No expression of p14^ARF mRNA was detected in 45.8%(22/48) of gastric cancers. Moreover, the negative rate (100%, 3/3) of p14^ARF mRNA of gastric cancers with the combined methylation of exons 1β and 2 was significantly higher than that (15%, 3/20) of the sole methylation of exon2(P＜0.05). CONCLUSION:p14^ARF gene is frequently inactivated by homozygous deletion and methylation of the 5' CpG islands in gastric cancer, which may play an important role in the development of gastric cancer.     

Effect of over-expression of transcription factor CDX2 on proliferation and cell cycle of human gastric cancer cell line SGC-7901

AIM: To study the effect and the molecular mechanism of CDX2 over-expression on the proliferation, growth and cell cycle of human gastric cancer cell line SGC-7901. METHODS: The SGC-7901 cells in LV-CDX2-GFP group were transfected with the recombinant lentivirus vector LV-CDX2-GFP, the cells in LV-GFP group were transfected with the negative control lentiviral vector for the negative control, and the cells in blank control group were without any treatment. The cell proliferation was detected by CCK-8 assay. The cell cycle distribution was analyzed by flow cytometry. The expression of CDX2, Bax, Bcl-2, cyclin D1 and survivin was determined by semi-quantitative RT-PCR and Wes-tern blotting. RESULTS: Compared with LV-GFP group and blank control group, the proliferation activity of the SGC-7901 cells was significantly lower (P<0.05), the G0/G1 phase proportion increased (P<0.05), the mRNA and protein levels of Bcl-2, cyclin D1 and survivin were reduced (P<0.05), and the mRNA and protein levels of Bax were up-regulated (P<0.05) in LV-CDX2-GFP group. No statistically significant difference of the above indexes was observed (P>0.05) between LV-GFP group and blank control group. CONCLUSION: Over-expression of CDX2 mediated by lentivirus inhibits the proliferation and growth of human gastric cancer SGC-7901 cells and arrestes the cell cycle at G0/G1 phase, which may be related to down-regulation of Bcl-2, cyclin D1 and survivin and up-regulation of Bax.     

Expression of natural killer cell stimulatory receptor NKG2D and its ligand MICA in Tibetan patients with gastric cancer at Qinghai plateau

AIM: To investigate the expression of natural killer cell stimulation receptor D(NKG2D) in peripheral blood and the expression of major histocompatibility complex class I chain-related protein A(MICA) on the gastric carcinoma tissue and the neighboring non-cancerous tissue in Tibetan patients with gastric cancer at Qinghai plateau. METHODS: Samples of 33 patients and 20 healthy persons were collected to detect NKG2D in peripheral blood by Flow cytometry analysis. The expressions of MICA in part of the correspondent tissues were examined by RT-PCR and immunohistochemistry.RESULTS: The expression of NKG2D in the plateau of Tibetan patients with gastric cancer group (13.47 ±5.26)% was significantly lower than that in healthy groups (32.62±10.08)%. The mRNA level of MICA in gastric cancer was significantly higher than that in neighboring non-cancerous tissue (P<0.05). The expressions of MICA proteins showed a significant difference between the neighboring non-cancerous tissue (21.21%, 7/33) and the gastric carcinoma tissue (78.79%, 26/33), between the high differentiation (60.00%, 3/5) and the moderate (72.73%, 8/11), low differentiation (88.24%, 15/17). The expressions of MICA were not correlated with tumor size, sex, age, lymph node metastasis of the patients (P>0.05). Spearman rank correlation displayed that the expressions of MICA mRNA were positively correlated with the MICA protein level (r=0.903, P<0.01).CONCLUSION: The immune escape in Tibetan patients with gastric cancer at Qinghai plateau probably relates to the down-regulation of NKG2D and the up-regulation of its ligand MICA. The activity of NK cells and the anti-cancer cellular immunity level are descending in the plateau of Tibetan patients with gastric cancer. The decrease in the receptor NKG2D is a reason for the activity of NK cell descending.     

Apoptosis induction in gastric carcinoma cells by celecoxib combined with adriamycin

AIM:To study the apoptosis induction of cyclooxygenase-2 (COX-2) inhibitor，celecoxib and adriamycin (ADM) on tumor apoptosis of gastric carcinoma MGC-803 cells, and to explore their possible molecular mechanism(s) and interactions.METHODS:The number of MGC-803 cells was observed by MTT assay. Tumor apoptosis was studied by fluorescence microscopy, flow cytometry (FCM), and DNA ladder. RESULTS:MGC-803 cell number was significantly decreased with increasing dose of ADM. Cells were accumulated in G₀/G₁ phase and the number of cells in S phase was decreased. ADM (5 mg/L) combined with celecoxib (25 μmol/L) markably inhibited the growth of MGC-803 cells. Significant morphological changes of typical apoptosis were observed after treatment with combined use of celecoxib and ADM. Compared with ADM or celecoxib alone, ADM plus celecoxib obviously enhanced the DNA ladder fragment revealed by agarose gel electrophoresis of DNA. After exposure to combined celecoxib and ADM treatment for 48 h, MGC-803 cells were accumulated in G₀/G₁ phase. There was a decrease in the number of cells in S phase as compared to celecoxib or ADM alone. CONCLUSION:Celecoxib and ADM appear to have synergistic effects for the apoptosis induction. This may be an important prospect for applying COX-2 inhibitors to assist chemical therapy of ADM in clinical use.     

Expression of microRNA-1284 in gastric cancer and underlying mechanism

AIM: To evaluate the correlation between microRNA-1284 (miR-1284) and gastric cancer, and to investigate the underlying mechanism. METHODS: The expression of miR-1284 was examined by real-time PCR in 63 gastric cancer (GC) tissue samples and 63 non-malignant adjacent tissue samples. The correlation between miR-1284 and the clinicopathological feature of GC was analyzed. Lentiviral vector containing miR-1284 was constructed and transfected into GC SGC-7901 cells. After transfection, the expression of miR-1284 was examined by real-time PCR. The cell activity was evaluated by CCK-8 assay. The cell cycle and apoptosis were determined by flow cytometry. The ability of cell migration was measured by wound-healing assay. The potential target gene of miR-1284 was predicted by online bioinformatic softwares. The expression of JAG1 mRNA was examined by real-time PCR. The protein levels of JAG1, Notch1 and NF-κB were analyzed by Western blotting. RESULTS: Compared with non-malignant adjacent tissue samples, the results of real-time PCR showed significant downregulation of miR-1284 in 42 GC tissue samples (P<0.05). The expression level of miR-1284 was not significantly associated with age and gender of the patients, tumor size, TNM staging and lymph node metastases (P>0.05), but significantly associated with histologic grading (P<0.05). Compared with LV-NC-GFP group and control group, after transfection of miR-1284 in LV-miR-1284 group, the expression of miR-1284 was significantly increased (P<0.05), the percentages of apoptotic cells and the cells in G₀/G₁ phase were significantly increased (P<0.05), the cells activity and ability of migration were significantly decreased (P<0.05), and the expression of JAG1, Notch1 and NF-κB was significantly decreased (P<0.05). CONCLUSION: The inhibitory effect of miR-1284 on gastric cancer may be associated with the regulation of its targeting gene JAG1.     

Relationship between genetic instability of nm23H1 gene and clinical pathological behaviors in gastric cancer and colonic cancer

AIM: To study the relationship between genetic instability of nm23H1 gene and clinical pathological behaviors in Chinese with gastric cancer and colonic cancer, and provide experimental basis for the mechanism of nm23H1 gene and tumor metastasis. METHODS: This study was conducted on 40 gastric carcinomas and 30 colonic carcinomas. Techniques such as DNA extraction from formalin-fixed paraffin-embedded tissues, PCR-SSCP, ordinary silver stain were used to study microsatellite instability (MSI) and loss of heterozygosity (LOH) of locus D17S396. Envision immunohistochemistry and Leica-Qwin computer imaging techniques were used to assess the expression of nm23H1 protein. RESULTS: In both gastric cancer and colonic cancer, the frequency of MSI was higher in TNM stageⅠandⅡthan that in stage Ⅲ and Ⅳ, while LOH was just opposite. Moreover, the frequency of LOH in lymph node metastasis cases was significantly higher than that without lymph node metastasis cases. The positive frequency of nm23H1 protein with lymph node metastasis was lower than that without lymph node metastasis cases. TNM stage III and IV also exhibited lower nm23H1 protein positive frequency compared with stage I and II. CONCLUSION: MSI and LOH can control the carcinogenesis and metastasis of gastric cancer and colonic cancer through different approaches. MSI may be an early period molecule marker of gastric cancer and colonic cancer. In contrast, LOH appears mostly in the late period of gastric cancer and colon cancer, indicating a high aggressive and poor prognosis.     

Effect of captopril on AGS nude mouse model of gastric cancer

AIM: To observe the effect of captopril on the genesis and development of gastric cancer, and to explore its clinical treatment feasibility for gastric cancer. METHODS: The human gastric cancer cell line AGS was used to establish a tumor model in nude mice, and the model mice were randomly divided into 3 groups: positive control (5-fluorouracil) group, normal control (saline) group and experimental (captopril) group. After intraperitoneal injection or intragastric administration of the drugs, the tumor growth curve was determined, and the tumor tissues were also sampled to detect the expression of Ki-67, STAT3, Bax and Bcl-2 by real-time quantitative PCR and immunohistochemistry. The apoptosis was detected by TUNEL+DAPI staining. RESULTS: The tumor growth curve showed that the tumor model in the nude mice was successfully established. The tumor volumes among groups showed significantly different after 14 d growth. The increase in the tumor volume in normal control group was significantly faster than that in the other two groups, and that in positive control group was the slowest. The expression of Bax in captopril group increased, and the expression of STAT3, Ki-67 and Bcl-2 was reduced as compared with normal control group and positive control group. Compared with normal control group, the apoptotic rate increased significantly, and the protein expression of p-STAT3 and STAT3 decreased obviously in positive control group and captopril group. CONCLUSION: With better feasibility, angiotensin-converting enzyme inhibitor captopril has a significant effect on treating gastric cancer in the AGS nude mouse model by regulating the expression of STAT3, Bax, Bcl-2 and Ki-67 to accelerate the apoptosis of cancer cells, thus inhibiting tumor growth.     

Central role of GRP78 in growth of gastric carcinoma cells

AIM: To explore the effect of glucose-regulated protein 78 (GRP78) on the gastric carcinogenesis. METHODS: GPR78 expression patterns were examined in 34 specimens from gastric carcinoma patients using the immunohistochemistry (IHC) assay, and in 10 specimens using Western blotting analysis. In addition, the expression of GPR78 and cyclin D1 was detected in human gastric cancer cell lines SGC7901 and SGC7901-H78 (overexpressing GRP78) by Western blotting. RESULTS: By IHC assay, GRP78 was found to be highly expressed in the cytoplasm of gastric carcinomas as compared with the adjacent non-malignant tissues and corresponding normal tissues. GRP78 expression was positively correlated with gender and histological differentiation (P<0.05), but not with age, tumor stage and lymph node metastasis (P>0.05). Furthermore, we found that with the increased expression of GRP78 in SGC7901-H78 cells, the expression of cyclin D1 was also elevated. CONCLUSION: GRP78 might be a key player to be involved in the growth of gastric cancer.     

Study on the expression of pituitary tumor-transforming (PTTG) and fragile histidine triad (FHIT) in gastric cancer and pericancerous tissues

AIM:To Study on the expressive levels of PTTG and FHIT and detect their clinicopathological significances in gastric cancer and pericancerous tissues.METHODS:Immunohistochemical method was used on routinely paraffin-embedded sections of 49 cases with gastric cancer and 20 subjects with pericancerous tissues. RESULTS:The positive rate and score of PTTG in gastric cancer were significantly higher than those in pericancerous tissues (P<0.05,P<0.01),but those of FHIT were opposite (P<0.05,P<0.01),the positive cases of PTTG and negative subjects of FHIT showed severely-atypical hyperplasis. The positive rate and score of PTTG were significantly lower in the cases of infiltrating depth T₁-T₂ and without-metastasis of distant organs than those in the subjects of infiltrating depth T₃-T₄ and with-metastasis of distant organs(P<0.05,P<0.01). The positive rate and score of FHIT were significantly higher in the cases of infiltrating depth T₁-T₂,without-metastasis of lymphnodes,with-metastasis of the first site lymphnodes,and without metatstasis of distant organs than those in the subjects of infiltrating depth T₃-T₄,with-metastasis of lymphnodes,with-metastasis of the third site lymphnodes,and with-metastasis of distant organs(P<0.05,P<0.01). The significantly negative correlation was found between the score of PTTG and FHIT in gastric cancer tissues(r=-0.36,P<0.01). CONCLUSION:The expression of PTTG and FHIT might be important biological markers for reflecting the carcinogenesis,progression,invasive potential,metastastic status and prognosis of gastric cancer. The assays of PTTG and FHIT in benign lesions might have clinical values for the prevention and early-stage finding of gastric cancer.     

Prognostic significance of FOXA1 and BRCA1 expression in triple negative breast cancer

AIM: To investigate the expression of forkhead box protein A1(FOXA1) BRCA1 protein,P53 and vascular endothelial growth factor (VEGF) in triple negative breast cancer (TNBC) and non-TNBC, and the relevance with the clinicopathological parameters for evaluating the prognosis. METHODS: The tumor samples were collected from 113 cases of breast cancer patients in the First Affiliated Hospital of Jinan University,and divided into TNBC group, luminal subtype group and HER-2 overexpression subtype group by the immunohistochemical results of estrogen receptor, progesterone receptor and HER-2. EnVision two-step method was used to detect the expression of FOXA1, BRCA1, P53 and VEGF in the tumor samples. RESULTS: Total FOXA1 positive expression rate was 63.7% (72/113), with 45.2% (19/42) in TNBC, 88.0% (44/50) in luminal subtype and 42.9% (9/21) in HER-2 overexpression subtype.The statistically sigfnificant difference among the 3 groups was observed (P<0.01). Total BRCA-1 positive expression rate was 47.8% (54/113), with 66.7% (28/42) in TNBC, 44.0% (22/50) in luminal subtype and 19.0% (4/21) in HER-2 overexpression subtype.The statisticallysignificant difference among the 3 groups was also observed (P<0.01). In the cases of clinical stages Ⅰ~Ⅱand histological grades 1~2, FOXA1 positive rate was higher than the FOXA1 negative rate (P<0.01). Negative correlations between FOXA1 positive rate and expression of P53/VEGF, and between FOXA1 positive rate and the recurrence rate were found (P<0.05). In the cases of clinical stages Ⅱ~Ⅲ and histological grades 2~3, the BRCA1 positive rate was higher than the BRCA1 negative rate (P<0.05). Positive correlations between BRCA-1 positive rate and the expression of P53/VEGF, and between BRCA1 positive rate and the recurrence rate were also observed (P<0.05). CONCLUSION: Expression of FOXA1 and BRCA1 in breast cancer is different. BRCA1 may be an adverse prognostic indicator for triple negative breast cancer.     

Level and clinical significance of RNA oxidative damage in human gastric cancer and para-carcinoma tissues

AIM: To investigate the RNA oxidative damage in human gastric cancer tissue and para-carcinoma tissue for exploring the role of RNA oxidation in the occurrence of gastric cancer. METHODS: Immunohistochemical observation and LC-MS/MS analysis were performed in 61 cases of gastric carcinoma. The position and concentration of 8-oxoguanosine (8-oxoGsn) were detected, respectively. RESULTS: The results of immunohistochemical observation showed that 8-oxoGsn was obviously up-regulated in the gastric cancer. The positive staining mainly accumulated in the cytoplasm of the tumor cells. The results of mass spectrometry showed that the level of 8-oxoGsn in the gastric cancer tissues was higher than that in the para-carcinoma tissues (P<0.05). CONCLUSION: 8-oxoGsn is up-regulated in gastric cancer. RNA oxidative damage may play important roles in the occurrence of gastric cancer.