Standard Lymphadenectomy for Esophageal and Lung Cancer: Variability in the Number of Examined Lymph Nodes Among Pathologists and Its Survival Implication

AIM

We compared variability in number of examined lymph nodes between pathologists and analyzed survival implications in lung and esophageal cancer after standardized lymphadenectomy.

METHODS

Outcomes of 294 N2 dissected lung cancer patients and 132 2-field dissected esophageal cancer patients were retrospectively examined. The primary outcome was difference in reported lymph node count among pathologists. Secondary outcomes were overall and disease-specific survival related to this count and survival related to the 50% probability cut-off value of detecting metastasis based on the number of examined lymph nodes.

RESULTS

The median number of examined lymph nodes in lung cancer was 13 (IQR 9-17) and in esophageal cancer it was 22 (18-29). The pathologist with the highest median number of examined nodes had > 50% higher lymph node yield compared with the pathologist with the lowest median number of nodes in lung (15 vs. 9.5, p = 0.003), and esophageal cancer (28 vs. 17, p = 0.003). Survival in patients stratified by median reported lymph node count in both lung (adjusted RMST ratio < 14 vs. ≥ 14 lymph nodes 0.99, 95% CI 0.88-1.10; p = 0.810) and esophageal cancer (adjusted RMST ratio < 25 vs. ≥ 25 lymph nodes 0.95, 95% CI 0.79-1.15, p = 0.612) was similar. The cut-off value for 50% probability of detecting metastasis by number of examined lymph nodes in lung cancer was 15.7 and in esophageal cancer 21.8. When stratified by this cut-off, no survival differences were seen.

CONCLUSION

The quality of lymphadenectomy based on lymph node yield is susceptible to error due to detected variability between pathologists in the number of examined lymph nodes. This variability in yield did not have any survival effect after standardized lymphadenectomy.

Routine preoperative MRCP in screening choledocholithiasis in acute cholecystitis compared to selective approach: a population-based study

Choledocholithiasis is more common in acute cholecystitis than in elective situations. Preoperative diagnosis of choledocholithiasis is essential to facilitate adequate planning of CBD (common bile duct) stone removal, preferably performed as a single-stage procedure. The purpose of this study was to test the feasibility of routine preoperative magnetic resonance cholangiopancreatography (MRCP) in acute cholecystitis followed by consequent cholecystectomy. A total of 180 consecutive patients operated for acute cholecystitis between January 2019 and December 2019 were prospectively enrolled. Preoperative routine MRCP was performed for bile duct evaluation when feasible. The control cohort consisted of 180 consecutive patients undergoing emergency laparoscopic cholecystectomy before the study period. Intraoperative cholangiography was used routinely in both groups when technically achievable. We examined the proportion of patients recruited in preoperative MRCP, possible time delay to MRCP and surgery, and the incidence of CBD stones compared to the control cohort. Routine MRCP in acute cholecystitis was achieved in 114/180 (63%) patients compared to 42/180 (23.3%) patients of the control group. The triage time from emergency to MRCP and the operating theatre was similar in both cohorts. The percentage of patients diagnosed with choledocholithiasis in the study group was notably higher (almost 18% vs 11%), p < 0.05. After a median follow-up time of 2.5 years in the study group and almost 4 years in the control group, recurrent choledocholithiasis was not detected in either group. Routine MRCP in patients with acute cholecystitis can be implemented with a fair execution rate in a population-based setting with minor effects on hospital stay and delays but higher detection of choledocholithiasis. We observed no additional benefit compared to the selective use of MRCP. However, routine preoperative MRCP allows an advantage when considering the appropriate exploration method if choledocholithiasis is detected.

Tertiary lymphoid structures and gastric cancer prognosis

Tertiary lymphoid structures (TLSs) are part of immune response against cancer. Their high density and high diameter have been shown to be associated with prognosis in different cancer types. The aim of this study was to examine the prognostic significance of TLS density and diameter in gastric cancer and reproducibility of their assessments. TLS densities and maximal TLS diameter were assessed from hematoxylin-eosin (HE) stained slides of 721 surgically treated gastric cancer patients from two hospitals in Finland. Mortality hazard ratios (HRs) for TLS densities and maximal TLS diameter were analyzed. TLS densities and maximal TLS diameter were assessed with moderate interobserver agreement (Cohen's kappa 0.50-0.62). Maximal TLS density was not associated with survival (adjusted HR 0.85, 95% CI 0.70-1.02) and neither was hotspot TLS density (adjusted HR 0.85, 95% CI 0.70-1.02). High maximal TLS diameter was associated with longer survival in overall study population (adjusted HR 0.74, 95% CI 0.61-0.89) and in diffuse type subgroup (adjusted HR 0.65, 95% CI 0.50-0.85). In conclusion, high maximal TLS diameter is associated with improved survival in gastric cancer and can be assessed from HE-stained slides. Its prognostic value might be limited to diffuse histological type.

Increasing Use of PET-CT, Neoadjuvant Treatment, Minimally Invasive Approach and Surgical Radicality in Esophageal Cancer Surgery are Associated with Improved Short- and Long-term Outcomes in Real-World Setting

BACKGROUND

Guideline adherence has improved outcomes in several cancers. Our aim was to evaluate whether the rate of PET-CT, neoadjuvant treatment, minimally invasive approach, and surgical radicality, suggested also by recent guidelines, would improve short- and long-term operative outcomes in esophageal cancer in real-world setting.

METHODS

This retrospective study in two Finnish Hospitals between 2010 and 2020 included 296 esophageal cancer patients. Grouping factors based on four factors with annual cut-offs by center were 90% rate in PET-CT-based staging, 70% in neoadjuvant therapy usage, 80% in minimally invasive approach, and 20 in annual mean lymph node yield. If none of factors were reached, all patients operated in that year were classified into group 1. With one to three cut-offs reached, grouping was into group 2. If all annual cut-offs were reached, patients were classified into group 3. Primary end points were major complication rate and overall 1-, 3-, and 5-year survival.

RESULTS

Major complication rate decreased significantly from 38.2% in group 1 (p < 0.001) and 34.2% in group 2 (p < 0.001) to 10.2% in group 3. Overall 1-, 3-, and 5-year survival rates between groups 1-3 were 77.9% vs. 80.3% vs. 94.2% (p = 0.004), 51.5% vs. 51.1% vs. 67.3% (p = 0.022), and 44.1% vs. 47.4% vs. 55.5% (p = 0.065), respectively. Adjusted 5-year overall mortality was reduced significantly in group 3 compared to group 1 (HR 0.46, 95% CI 0.28-0.75).

CONCLUSION

This study suggests that increasing rate of PET-CT, neoadjuvant treatment, minimally invasive surgery, and surgical radicality improves short- and long-term outcomes in operated esophageal cancer patients.

Minimally invasive esophagectomy learning curves with different types of background experience

Background

Minimally invasive esophagectomy (MIE) is a complex procedure with learning associated morbidity. The aim was to evaluate the learning curve for MIE focusing on short-term outcomes in two settings: (I) experienced MIE surgeon in new hospital (Hospital 1); (II) surgeons experienced with open esophagectomy and minimally invasive surrogate surgery (Hospital 2).

Methods

In Hospital 1 and Hospital 2, on intent-to-treat basis number of MIEs were 132 and 57, respectively. The primary outcomes were major complications and anastomosis leaks. Secondary outcomes were operative time, blood loss, lymph node yield, hospital stay and 1-year mortality. Length of learning curves were analyzed with risk-adjusted cumulative sum (RA-CUSUM) method.

Results

In Hospital 1, major complication and anastomosis leak rates were 9.8% and 4.5%, 22.8% and 12.3% in Hospital 2, respectively. In Hospital 1, complication and leak rates remained stable. In Hospital 2, improvement occurred after 34 cases in major complications and 29 cases in leaks. Of secondary outcomes, improvements were seen in Hospital 1 in operative time after 61, blood loss after 86, lymph node yield after 52, hospital stay after 19 and 1-year mortality after 24 cases. In Hospital 2, improvement occurred in operative time after 30, blood loss after 15, lymph node yield after 45, hospital stay after 50 and 1-year mortality after 15 cases.

Conclusions

According to this study, learning phase of the individual surgeon determines the outcomes of MIE, not the institutional learning phase.

Exercise capacity in the stair-climbing test predicts outcomes of operable esophageal cancer in minimally invasive era

INTRODUCTION

The risk of complications after esophagectomy highlights the need for careful preoperative assessment. Aim was to assess whether stair-climbing test (SCT) could predict outcomes of patients with operable esophageal cancer in minimally invasive era.

MATERIALS AND METHODS

Patients with esophageal cancer were evaluated for surgical treatment in Central Finland Central Hospital from 2012 to March 2021. Of evaluated 162 patients, 138 were scheduled to eventually undergo surgery. The exercise capacity was evaluated with symptom limited SCT. Patients were divided into four study groups on intent-to-treat basis: surgery and the SCT >14 m (Group 1), surgery and the SCT <11 m (Group 2), non-surgical therapy and the SCT <11 m (Group 3) and non-surgical therapy and the SCT >14 m (Group 4). Results were adjusted for confounders.

RESULTS

Major complication rate was 10.1% vs 40.0% between Group 1 and 2 (p = 0.006), and 90-day mortality 0% vs 20.0% (p < 0.001). Overall survival rates in Groups 1-4 at 1-year were 92.3% vs 72.2% vs 46.8% vs 81.8%, at 3-year 68.5% vs 52.7% vs 15.6% vs 27.3% and at 5-year 58.7% vs 39.5% vs 0% vs 0%, respectively (p < 0.001). In adjusted analysis when compared to Group 1, other groups had increased 5-year mortality hazard (Group 2 HR 2.88 (95% CI 1.25-6.63), Group 3 HR 15.6 (95% CI 5.57-43.5) and Group 4 HR 5.35 (95% CI 2.08-13.7)).

CONCLUSION

Exercise capacity measured with SCT in esophageal cancer patients is a strong predictor of complications and survival, and is a potential parameter to be included in any risk or prognostic models.

Laparoscopic treatment of small bowel strangulation caused by an intramesosigmoid hernia and review of literature

An internal hernia is defined as a protrusion of an abdominal viscera through the defects of the gastrointestinal mesentery or peritoneum-lined fossa. Sigmoid mesocolic hernias are an uncommon type of internal hernias, accounting for only 6% of all internal hernias. Furthermore, intramesosigmoid hernia is one of the three subtypes of the sigmoid mesocolic hernias. Internal hernias are potentially fatal conditions with diagnostic challenges. Patients presenting with acute obstruction, no surgical history and no external hernia should receive an urgent CT scan to facilitate early surgery and to minimise the risk of strangulation and bowel resection. Here, we report a case of strangulated small bowel obstruction secondary to an intramesosigmoid hernia with a successful laparoscopic repair. We also present a literature review of all reported cases so far and give an up-to-date perspective on intramesosigmoid hernia.

Benchmark values for transthoracic esophagectomy are not set as the defined "best possible"-a validation study

Background

Recently, benchmark values for low-comorbidity patients at high-volume centers were set to define "best achievable results" for transthoracic minimally invasive esophagectomy (MIE). We aimed to validate suggested benchmark values by comparing them to outcomes at a medium-volume center in Finland.

Methods

All MIEs (n=82) performed at Central Finland Central Hospital between September 2012 and November 2017 including 75 totally MIE and 7 hybrid procedures. The aim of the study was to compare the results to previously suggested benchmark parameters for postoperative morbidity measured with the Clavien-Dindo classification and comprehensive complication index. Target benchmark parameters were ≤55.7% for any complications, ≤30.8% for major complications (Clavien-Dindo ≥3a), ≤40.8% for 30-day and ≤42.8% for 90-day comprehensive complication index, ≤20% for anastomosis leak, ≤31.6% for pulmonary complications, ≤1.0% for 30-day mortality and ≤4.6% for 90-day mortality.

Results

Compared with benchmark patients, our patients were older (median 68 vs. 58 years), with more comorbidities. All parameters measuring complications showed better results in our study than benchmark values. Median intensive care unit stay of 1 (IQR, 1-1) and hospital stay of 9 (IQR, 9-12) days were also shorter. At least 1 complication developed in 45.1%, and 6.1% faced major morbidity. Median (IQR) comprehensive complication index for both 30 and 90 days was 0 (IQR, 0-20.9 days). Anastomosis leak and pulmonary complications were observed in 3.7% and 22.0%, respectively. The 30- and 90-day mortality was 1.2% (1/82).

Conclusions

Benchmark values assessing postoperative morbidity after MIE do not represent the defined "best achievable" results after completed learning curves.

Cost-analysis and effectiveness of one-stage laparoscopic versus two-stage endolaparoscopic management of cholecystocholedocholithiasis: a retrospective cohort study

BACKGROUND

One-stage laparoscopic common bile duct (CBD) stone clearance and laparoscopic cholecystectomy (LCBDE+LC) for cholecystocholedocholithiasis ( CCL) can be performed with similar short and long-term outcomes than two-stage endoscopic retrograde cholangiography followed by subsequent LC (ERCP+LC). This study examined retrospectively the outcome and hospital costs of one-stage versus two-stage treatment of CBD stones.

METHODS

From January 1999 and December 2014, 217 consecutive, elective patients underwent one-stage (LCBDE + LC ) or two-stage (ERCP + subsequent LC ) treatment for CBD stones. The data from the one-stage management was collected prospectively, and from the two-stage management retrospectively. The main measure of outcome was hospital costs, with the success of one-stage versus two-stage management, postoperative morbidity and postoperative stay as secondary outcome measures.

RESULTS

One-stage laparoscopic transcystic management was the least costly option compared to laparoscopic one-stage transductal approach (TC 5455€ versus TD 9364, p < 0.001) or two-stage management (6913 €, p = 0.02). Overall success rate of primary intervention (including conversions to open surgery) for CBD stone clearance was 96.9%, 97.0% and 98.3% after transcystic one-stage, transductal one-stage and two-stage approach, p = 0.79. Postoperative morbidity was 15.5% versus 7.5%, p = 0.64, and postoperative hospital stay median 2 days (IQR 2-5) versus 4.5 days ( IQR 3-7), p < 0.001 in the one-stage and two-stage management groups.

CONCLUSIONS

Our study shows that laparoscopic one-stage transcystic management of CCL results in high rate of CBD clearance, fewer procedures per patient, shorter hospital and lower costs than the two-stage management. Therefore the one-stage transcystic management seems to be an attractive strategy for the treatment of CCL depending on local resources and surgical expertise .

Surgical care quality and oncologic outcome after D2 gastrectomy for gastric cancer

AIM: To examine the quality of surgical care and long-term oncologic outcome after D2 gastrectomy for gastric cancer.

METHODS: From 1999 to 2008, a total of 109 consecutive patients underwent D2 gastrectomy without routine pancreaticosplenectomy in a multimodal setting at our institution. Oncologic outcomes together with clinical and histopathologic data were analyzed in relation to the type of surgery performed. Staging was carried out according to the Union for International Cancer Control criteria of 2002. Patients were followed-up for five years at the outpatient clinic. The primary measure of outcome was long-term survival with the quality of surgery as a secondary outcome measure. Clinical data were retrospectively collected from the patient records, and causes of death were obtained from national registries.

RESULTS: A total of 109 patients (58 men) with a mean age of 67.4 ± 11.2 years underwent total gastrectomy or gastric resection with D2 lymph node dissection. The tumor stage distribution was as follows: stage I, (27/109) 24.8%; stage II, (31/109) 28.4%; stage III, (41/109) 37.6%; and stage IV, (10/109) 9.2%. Forty patients (36.7%) received chemotherapy or chemoradiotherapy. The five-year overall survival rate for all 109 patients was 45.0%, and was 47.1% for the 104 patients treated with curative R0 resection. The five-year disease-specific survival rates were 53.0% and 55.8%, respectively. In a multivariate analysis, body mass index and tumor stage were independent prognostic factors for overall survival (both P < 0.01), whereas body mass index, tumor stage, tumor site, Lauren classification, and lymph node invasion were prognostic factors for cancer-specific survival (all P < 0.05). Postoperative 30-d mortality was 1.8% and 30-d, surgical (including three anastomotic leaks, two of which were treated conservatively), and general morbidities were 26.6%, 12.8%, and 14.7%, respectively.

CONCLUSION: D2 dissection is a safe surgical option for gastric cancer, providing quality surgical care and long-term oncologic outcomes that are in line with current Western standards.

Cyclooxygenase-2 and gastric cancer

Gastric cancer remains a leading cause of cancer-related deaths worldwide, although its incidence has been steadily declining during recent decades. Expression of cyclooxygenase-2 (COX-2) is elevated in gastric carcinomas and in their precursor lesions. COX-2 expression associates with reduced survival in gastric cancer patients, and it has also been shown to be an independent factor of poor prognosis. Several molecular mechanisms are involved in the regulation of COX-2 expression in gastric cancer cell lines, including signal transduction pathways activated by Helicobacter pylori. In gastric tumor models in vivo the role of COX-2 seems to be predominantly to facilitate tumor promotion and growth.

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.

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.

15-hydroxyprostaglandin dehydrogenase is down-regulated in gastric cancer

PURPOSE

We have investigated the expression and regulation of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in gastric cancer.

EXPERIMENTAL DESIGN

Clinical gastric adenocarcinoma samples were analyzed by immunohistochemistry and quantitative real-time PCR for protein and mRNA expression of 15-PGDH and for methylation status of 15-PGDH promoter. The effects of interleukin-1beta (IL-1beta) and epigenetic mechanisms on 15-PGDH regulation were assessed in gastric cancer cell lines.

RESULTS

In a gastric cancer cell line with a very low 15-PGDH expression (TMK-1), the 15-PGDH promoter was methylated and treatment with a demethylating agent 5-aza-2'-deoxycytidine restored 15-PGDH expression. In a cell line with a relatively high basal level of 15-PGDH (MKN-28), IL-1beta repressed expression of 15-PGDH mRNA and protein. This effect of IL-1beta was at least in part attributed to inhibition of 15-PGDH promoter activity. SiRNA-mediated knockdown of 15-PGDH resulted in strong increase of prostaglandin E(2) production in MKN-28 cells and increased cell growth of these cells by 31% in anchorage-independent conditions. In clinical gastric adenocarcinoma specimens, 15-PGDH mRNA levels were 5-fold lower in gastric cancer samples when compared with paired nonneoplastic tissues (n = 26) and 15-PGDH protein was lost in 65% of gastric adenocarcinomas (n = 210).

CONCLUSIONS

15-PGDH is down-regulated in gastric cancer, which could potentially lead to accelerated tumor progression. Importantly, our data indicate that a proinflammatory cytokine linked to gastric carcinogenesis, IL-1beta, suppresses 15-PGDH expression at least partially by inhibiting promoter activity of the 15-PGDH gene.

Decreased xanthine oxidoreductase is a predictor of poor prognosis in early-stage gastric cancer

BACKGROUND

Xanthine oxidoreductase (XOR) is a key enzyme in the degradation of DNA, RNA and high-energy phosphates. About half of the patients with breast cancer have a decrease in XOR expression. Patients with breast cancer with unfavourable prognosis are independently identified by the loss of XOR.

AIM

To assess the clinical relevance of XOR expression in gastric cancer.

METHODS

XOR levels were studied by immunohistochemistry in tissue microarray specimens of 337 patients with gastric cancer and the relation between XOR expression and a series of clinicopathological variables, as well as disease-specific survival, was assessed.

RESULTS

XOR was moderately decreased in 41% and was undetectable in another 14% of the tumours compared with the corresponding normal tissue. Decreased XOR was associated with advanced stage, deep tumour penetration, diffusely spread tumour location, positive lymph node status, large tumour size, non-curative disease, cellular aneuploidy, high S-phase fraction and high cyclooxygenase-2 expression, but not with p53 expression or Borrmann classification. Down regulation of XOR was associated with unfavourable outcome, and the cumulative 5-year gastric cancer-specific survival in patients with strong XOR expression was 47%, compared with 22% in those with moderate to negative expression (p<0.001). This was also true in patients with stage I-II (p = 0.01) and lymph node-negative (p = 0.02) disease, as well as in patients with smaller (< or =5 cm) tumours (p = 0.02).

CONCLUSION

XOR expression in gastric cancer may be a new marker for a more aggressive gastric cancer biology, similar to that previously reported for breast cancer.

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.

MMP-2 but not MMP-9 associated with COX-2 and survival in gastric cancer

BACKGROUND AND AIM

Matrix metalloproteinases (MMPs) MMP-2 and MMP-9 can degrade type IV collagen of extracellular matrix and basal membranes. As cyclo-oxygenase-2 (COX-2) has been shown to activate MMPs, creating one of the COX-2-promoted pathways of tumour growth and metastasis, the prognostic role of MMP-2 and MMP-9 in gastric cancer was assessed and their association with COX-2 expression was evaluated.

MATERIALS AND METHODS

Samples were collected from 342 consecutive patients operated on for gastric cancer, of which 315 were acceptable for MMP-2, MMP-9 and COX-2 immunohistochemistry. Specimens were stained with specific antibodies, evaluated and categorised by two interpreters, and then correlated with clinical data and survival.

RESULTS

Epithelial MMP-2 immunoreactivity was associated with male sex, high stage, advanced penetration depth, non-curative surgery, high COX-2 expression and poor survival. Stromal MMP-2 expression correlated with high stage, intestinal type and non-curative surgery whereas MMP-9 correlated only with intestinal type. Stage, intent of surgery and COX-2 were independent prognostic factors.

CONCLUSIONS

Epithelial MMP-2 expression in gastric cancer is associated with aggressive forms, COX-2 and poor survival, although MMP-2 was not an independent prognostic factor. In gastric cancer tumour growth is apparently induced by COX-2, and invasion is mediated by MMP-2.

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.