COX-2 is associated with proliferation and apoptosis markers and serves as an independent prognostic factor in gastric cancer.

Cyclooxygenase-2 (COX-2) is an important factor in gastric carcinogenesis, and COX-2 expression in gastric cancer patients correlates with prognosis. We have now studied the impact of COX-2 in comparison to six other tissue tumor markers, DNA index, and S-phase fraction (SPF) in a large series of gastric cancer specimens. From 342 consecutive patients, 337 archival tissue specimens were available for immunohistochemistry of COX-2, HuR, cyclin A, MMP-2, p53, p21, and Ki-67 and 313 for analysis of DNA index and S-phase fraction by flow cytometry. Associations between factors were assessed by chi-square test and survival analysis by the Kaplan-Meier method and Cox model. A significant association emerged between of COX-2 and p53 (p < 0.0001), Ki-67 (p = 0.013), DNA ploidy (p < 0.0001), and SPF (p < 0.0001). In an extended multivariate analysis, COX-2 and p53 expression were independent prognostic factors for poor survival, in addition to high stage and non-curative surgery. In gastric cancer, COX-2 expression associated with markers for apoptosis and proliferation, and furthermore, it was confirmed that COX-2 and p53 are strong prognostic indicators.

MMP-7 overexpression is an independent prognostic marker in gastric cancer.

To enable cancer to invade and to metastasize, the surrounding stroma must be degraded. Matrix metalloproteinase-7 (MMP-7) is capable of degrading many extracellular matrix proteins and cellular adhesions, is overexpressed in many malignancies, and plays a role in tumour progression. The purpose of this study was to evaluate the association between MMP-7 tissue expression and patients' prognosis in gastric cancer. From 264 patients who underwent surgery for gastric cancer, surgical specimens were collected on tissue array blocks and stained by immunohistochemistry for MMP-7. In 27 (10.2%) of the specimens, immunopositivity was found as high, in 50 (18.9%) as moderate and in 51 (19.3%) as weak. In 136 cases (51.5%), the immunopositivity was negative. A statistically significant correlation appeared between high MMP-7 expression and poor survival. In conclusion, our results suggest that MMP-7 expression may prove helpful in evaluating gastric cancer prognosis.

MYC-dependent regulation and prognostic role of CIP2A in gastric cancer.

BACKGROUND: Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently identified human oncoprotein that stabilizes the c-Myc (MYC) protein. However, the clinical relevance of CIP2A to human cancers had not been demonstrated, but the mechanism of its regulation and its clinical role in cancer were completely unknown. METHODS: Tissue microarrays consisting of 223 gastric adenocarcinoma specimens were evaluated for the presence of CIP2A using immunohistochemistry, and the association of CIP2A expression with survival was assessed using Kaplan-Meier analysis. The effects of MYC and CIP2A on each other's expression and on cell proliferation were investigated in several gastric cancer cell lines using small interfering RNAs to CIP2A and MYC and immunoblotting. To further evaluate the role of MYC in CIP2A regulation, an inhibitor of MYC dimerization, 10058-F4, and an inducible MycER model were used. RESULTS: Expression of CIP2A protein was associated with reduced overall survival for gastric cancer patients with tumors 5 cm or smaller, with a 10-year overall survival in the CIP2A-immunopositive group of 8.1% as compared with 37.6% in the CIP2A-negative group (difference = 29.5%, 95% confidence interval = 12.5% to 46.5%, P = .001). In gastric cancer cell lines, CIP2A depletion led to decreased proliferation and anchorage-independent growth of the cells, as well as to reduced stability and expression of MYC protein. Interestingly, MYC depletion led to reduced expression of CIP2A mRNA and protein. Moreover, experiments with an MYC inhibitor and activator suggested that MYC directly promotes CIP2A gene expression. Finally, CIP2A and MYC immunopositivities were associated in gastric cancer specimens (P = .021). CONCLUSIONS: CIP2A immunopositivity is a predictor of survival for some subgroups of gastric cancer patients. CIP2A and MYC appear to be regulated in a positive feedback loop, wherein they promote each other's expression and gastric cancer cell proliferation.

Comparison of the prognostic value of a panel of tissue tumor markers and established clinicopathological factors in patients with gastric cancer.

AIM: The purpose of this study was to assess if the addition of a panel of tumor markers to established clinicopathological factors could improve the accuracy of 5-year outcome prediction in gastric cancer. The studied markers were chosen to represent different aspects of tumor biology. PATIENTS AND METHODS: The expression of syndecan-1, tenascin-C, tumor-associated trypsin inhibitor (TATI), p53, p21 and bcl-2 was analyzed by immunohistochemistry informalin-fixed, paraffin-embedded specimens from 337 patients with gastric cancer. In addition, the DNA ploidy and S-phase fraction (SPF) were assessed by flow cytometry. RESULTS: The loss of epithelial syndecan-1, strong stromal syndecan-1, the loss of stromal tenascin-C, the loss of tumor tissue TATI, high p53 and high p21 expression, aneuploidy and high (> or =7.6%) SPF were all associated with an unfavorable prognosis in univariate survival analysis. In multivariate survival analysis, p53 (hazard ratio (HR) 1.58; confidence interval (CI) 95% 1.16-2.16), p21 (HR 1.67; CI 95% 1.09-2.56) and DNA ploidy (HR 1.50; CI 95% 1.10-2.05) were independent prognostic factors, in addition to penetration depth (pT), lymph node status (pN), age at diagnosis and estimated radicality of surgery. The difference in prognostic accuracy between a base model with pT, pN, age and radicality of surgery (area under the curve (AUC) 0.898; CI 95% 0.86-0.94) and an extended model including p53, p21 and DNA ploidy (AUC 0.900; CI 95% 0.86-0.94) was not statistically significant (p=0.85). CONCLUSION: In gastric cancer, p53 and p21 expression, as well as DNA ploidy, are independent prognostic factors in addition to standard clinicopathological factors. However, the established indicators of the extent of disease show an impressively high accuracy in 5-year outcome prediction and adding the examined tumor markers to the base model does not significantly improve the prognostic accuracy.

Prognostic significance of cyclin A in gastric cancer.

High level of cyclin A promotes carcinogenesis, and overexpression of cyclin A has been associated with poor prognosis of cancer patients. We validated the prognostic role of cyclin A in gastric cancer and evaluated its correlation with expression of an mRNA stability factor HuR. From 342 consecutive histologically confirmed gastric cancer patients were obtained 325 representative tissue specimens for cyclin A and 316 for HuR immunohistochemistry. Specimens were stained by cyclin A and HuR specific monoclonal antibodies. Nuclear immunostaining detected in > or =5% of the tumor cells was considered the cut-off for cyclin A positivity. Positive HuR immunoreactivity was scored as nuclear or cytoplasmic. Associations between scores, clinicopathological factors and survival were calculated by the chi2-test, Fisher's exact test, Kaplan-Meier test and Cox model. Cyclin A detected in the nuclei of cancer cells was positive in 55% (179 of 325) of the specimens; 40% (127 of 316) of the specimens had cytoplasmic and 88% (279 of 316) nuclear immunoreactivity of HuR. Cyclin A expression was an independent prognostic factor for poor survival. Cyclin A immunoreactivity was associated with old age, high stage, proximal location of the tumor, intestinal type, noncurative resection, advanced penetration depth and with nodal metastases but not distant metastases. Furthermore, cyclin A expression was associated with cytoplasmic HuR expression, whereas no association with nuclear HuR was evident. Cyclin A is an independent prognostic factor in gastric cancer, and one mechanism for its overexpression may depend on cytoplasmic localization of HuR.

Cyclooxygenase-2 is an independent prognostic factor in gastric cancer and its expression is regulated by the messenger RNA stability factor HuR.

PURPOSE: Cyclooxygenase-2 (COX-2) promotes carcinogenesis and its expression associates with clinicopathologic characteristics in gastric cancer. HuR is an mRNA binding protein that controls the stability of certain transcripts including COX-2. We evaluated the prognostic significance of COX-2 and HuR expressions in gastric cancer and whether there exists a link between HuR and COX-2 expressions. EXPERIMENTAL DESIGN: The study included 342 consecutive patients with histologically confirmed gastric adenocarcinoma, of whom 321 patients had tissue specimens available for COX-2 and 316 for HuR immunohistochemistry. Specimens were stained by COX-2- and HuR-specific monoclonal antibodies and scored by two independent observers. Correlation to clinical data and survival was assessed. TMK-1 gastric adenocarcinoma cells were treated with small interfering RNA against HuR and expressions of HuR and COX-2 were detected by immunofluorescence and Western blot analysis. RESULTS: Patients with low COX-2 expression had a cumulative 5-year survival of 53% and those with high COX-2 expression had 16% (P < 0.0001). In multivariate analysis, COX-2 was an independent prognostic factor (P = 0.003). Cytoplasmic HuR expression was associated with high COX-2 expression (P < 0.0001) and with reduced survival (P = 0.004) whereas nuclear positivity for HuR was not. When TMK-1 cells were treated with HuR small interfering RNA, expressions of HuR and COX-2 were reduced. CONCLUSIONS: High COX-2 is an independent prognostic factor in gastric cancer. Cytoplasmic expression of HuR associates with high COX-2 expression and with reduced survival, and tissue culture experiments show that HuR can regulate expression of COX-2 in gastric cancer cells.

Tenascin-C expression correlates with prognosis in gastric cancer.

OBJECTIVES: Tenascin-C is a hexameric extracellular matrix glycoprotein that is expressed during embryonic development and re-expressed in proliferative processes such as wound healing and tumorigenesis. Stromal tenascin-C may block tumor invasion and thus have a significant influence on tumor spread and prognosis. METHODS: In the present study, tissue expression of stromal tenascin-C was studied by immunohistochemistry in a series of 314 patients with gastric cancer. RESULTS: Strong tenascin-C positivity was seen in the stroma of the tumor in 122 (39%) cases. There was a correlation between strong tenascin-C expression and low stage (p = 0.002), superficial tumor penetration (p = 0.02), location of tumor at the distal third of the stomach (p = 0.03), and potentially curative surgery (p = 0.008). No significant correlation was found between tenascin-C positivity and nodal status, distant metastases, age, Laurén classification, gender, tumor size, or Borrmann classification. The cumulative 5-year survival in patients with strong tenascin-C expression was 42% compared to 26% in those with negative-to-moderate expression (p = 0.0053). In multivariate survival analysis stratified for estimated cure of surgery, stage of disease was the only independent prognostic factor. CONCLUSION: In conclusion, tenascin-C expression seems to correlate with cancer related survival in patients with gastric cancer, but may not add significant prognostic information to that provided by TNM stage.

The prognostic value of p27 in gastric cancer.

OBJECTIVES: p27 is a cyclin-dependent kinase inhibitor and a putative tumor suppressor preventing progression of the cell cycle from G1 phase. Recent studies have suggested loss of p27 to correlate with poor prognosis in patients with a variety of solid tumors. Results in gastric cancer are contradictory. We therefore decided to study the potential of p27 as a prognostic marker in a consecutively surgically treated, single-institution series of patients. METHODS: Using a monoclonal antibody against p27, immunohistochemistry was performed in paraffin-embedded tumor specimens from 316 patients. RESULTS: Loss of p27 immunoreactivity (< or = 5% of the cancer cell nuclei positive) was observed in 241 (76%) out of 316 stained tumors. We observed no significant correlation between the expression of p27 and stage of disease, tumor size, depth of tumor invasion, lymph node metastases, distant metastases, Laurén classification, Borrmann type, grade of differentiation, age or gender. There was no significant difference in gastric cancer specific overall survival between patients with low and high p27 expression. CONCLUSION: Our results add further doubt to the usefulness of p27 as a prognostic marker in gastric cancer.