The significances of lymph node micrometastasis and its correlation with E-cadherin expression in pT1-T3N0 gastric adenocarcinoma

Occult Tumour Cells in Lymph Nodes from Gastric Cancer Patients: Should Isolated Tumour Cells Also Be Considered?

INTRODUCTION

Regional lymph node metastasis is an important prognostic factor for patients with gastric cancer. Occult tumour cells (OTCs), including either micrometastases (MMs) or isolated tumour cells (ITCs), may be a key factor in the development of cancer recurrence in pN0 patients.

AIMS

We aimed to determine the frequency and prognostic significance for disease recurrence of OTCs.

MATERIALS AND METHODS

This retrospective cohort study included all consecutive patients with pN0 gastric adenocarcinoma between January 2000 and December 2011 (n = 73). Immunohistochemistry using the pan-cytokeratin antibody AE1/AE3 was used to detect OTCs in 1257 isolated lymph nodes.

RESULTS

OTCs were identified in 30 patients (41%), including 20 cases with MMs (27%) and 10 cases with ITCs (14%). Disease recurrence and cancer-related death were observed in 24 (33%) and 20 patients (27%), respectively, and both were significantly associated with the detection of OTCs. A significant difference was also observed for the mean survival time between patients with OTCs and those without OTCs [100 vs 158 months (p = 0.015)]. The presence of OTCs was statistically significantly associated with the Lauren classification, tumour size and lymphatic permeation. Multivariate analyses revealed that only age, T stage and the presence of ITCs in lymph nodes were independent factors for recurrence. The presence of ITCs increased the risk for recurrence by 11.1-fold.

CONCLUSIONS

In a significant proportion of patients diagnosed as stage pN0, OTCs may be identified in lymph nodes if carefully searched for, which can negatively affect their prognosis. The presence of ITCs was found to be an independent factor for recurrence and after proper validation should be considered during lymph node assessment for prognosis definition.

Clinicopathologic factors associated with recurrence and long-term survival in node-negative advanced gastric cancer patients

BACKGROUND

despite a better prognosis in node-negative advanced gastric cancer (GC), a proportion of patients have a tumor recurrence within five years and eventually die due to cancer-related causes. The present study aimed to evaluate the predictive factors of tumor recurrence and long-term survival in node-negative advanced GC.

METHODS

a total of 646 node-negative advanced GC patients who underwent a curative gastrectomy in our institution were included in the study. The impact of different clinicopathologic factors on tumor recurrence and overall survival were analyzed.

RESULTS

tumor recurrences were observed in 181 patients and the cumulative recurrence rate at two-years and five-years were 50.8% and 86.2%, respectively. Lymphovascular invasion, advanced T stage (T3-T4) and an inadequate number of retrieved lymph nodes (LNs) were independent predictive factors of tumor recurrence in node-negative advanced GC. Older age, an upper 1/3 tumor, lymphovascular invasion, infiltration growth pattern (INFγ) and the depth of tumor invasion (T4 stage) were independently associated with long-term survival. With regard to node-negative patients with ≥ 15 retrieved LNs, infiltration growth pattern (INFγ) and advanced T stage (T3-T4) were independent risk factors for both tumor recurrence and long-term survival.

CONCLUSION

in addition to lymphovascular invasion, inadequate RLNs and advanced T stage, the prognostic significance of infiltration growth pattern in node-negative advanced GC was especially emphasized. These risk factors should be considered when selecting candidates for adjuvant chemotherapy and postoperative surveillance.

miR-126: An indicator of poor prognosis and recurrence in histologically lymph node-negative gastric cancer

BACKGROUND

Few biomarkers are available for the prediction of prognosis and recurrence in lymph node (LN)-negative gastric cancer (GC) currently. miR-126 functions as a tumor suppressor in GC, however, its clinical significance in LN-negative GC remains unknown.

AIM

To investigate the associations of tissue miR-126 level with the clinicopathological characteristics and clinical outcome of LN-negative GC patients.

METHODS

Quantitative real-time polymerase chain reaction was performed to examine the tissue miR-126 level in 315 LN-negative GC patients who underwent curative gastrectomy with D2 lymphadenectomy. The associations of tissue miR-126 level with clinicopathological characteristics and clinical outcome were evaluated.

RESULTS

Compared with matched adjacent non-tumor tissues, miR-126 expression was significantly down-regulated in tumor tissues. A reduced tissue miR-126 level statistically correlated with aggressive clinicopathological characteristics, including larger tumor size, deeper local invasion, and poorer prognosis. Notably, multivariate analysis identified advanced T stage and low miR-126 level as independent predictors of the unfavorable prognosis and recurrence of LN-negative GC.

CONCLUSIONS

These results indicate for the first time that advanced T stage and low miR-126 level are predictors of unfavorable prognosis and recurrence in LN-negative GC patients. These parameters should be taken into account to stratify patients for adjuvant therapy and close follow-up.

Aberrant Cytokeratin 20 mRNA Expression in Peripheral Blood and Lymph Nodes Indicates Micrometastasis and Poor Prognosis in Patients With Gastric Carcinoma

Several studies suggest that peripheral blood and lymph node micrometastases may be a causative factor for gastric cancer recurrence. Cytokeratin 20 shows enriched expression in intestinal epithelial cells. This study aimed to evaluate the clinical utility of monitoring cytokeratin 20 levels in peripheral blood and lymph nodes of patients with gastric cancer for detecting micrometastasis and predicting prognosis. We detected messenger RNA levels of cytokeratin 20 in gastric cancer cell lines and in the peripheral blood of 125 patients (85 patients with gastric cancer and 40 patients with benign neoplasm) by fluorescence quantitative real-time polymerase chain reaction both before and after radical resection. In all, 1586 lymph node samples from 85 patients with gastric cancer were evaluated for cytokeratin 20 expression using real-time polymerase chain reaction, as well as by immunohistochemistry staining with anti-pan-keratin and anti-cytokeratin 20 antibodies. All patients underwent follow-up until cancer-related death or for more than 3 years after tumor resection. We found that elevated cytokeratin 20 expression in peripheral blood as detected by quantitative real-time polymerase chain reaction closely correlates with poor clinicopathological characteristics. Detecting cytokeratin 20 messenger RNA in the lymph nodes by quantitative real-time polymerase chain reaction enabled more accurate determination of the clinicopathological staging of gastric cancer, best treatment approach, and prognosis. Our findings show that patients with increased cytokeratin 20 messenger RNA expression in the peripheral blood or lymph nodes have a shorter time to recurrence and poorer overall survival.

The prognostic value of lymph nodes count on survival of patients with node-negative gastric cancer

The retrieved lymph node (LN) count has been validated as a prognostic factor in various cancers. However, the interaction between LN counts and patients' prognosis in gastric cancer with negative-LN metastasis is not fully studied. Surveillance, Epidemiology, and End Results Program (SEER)-registered gastric cancer patients were used for analysis in this study. Patients operated on for gastric cancer at N0 stage between 2004 and 2012 were identified from the SEER database. The association between the LN counts and survival was assessed using the Cox proportional hazards model. Patients were stratified into 1–4, 5−13, and > 13 subgroups according to LN count cut-off values determined by X-tile program, with the 5-year cause specific survival (CSS) rate of 64.8%, 72.5%, and 79.4%, respectively. LN count was also validated as an independently prognostic factor in multivariate Cox analysis (P < 0.001). In addition, nomograms including LN counts on CSS were established according to all significant factors, and the c-index was 0.703 (95% CI: 0.672−0.734). Further study indicated that patients with no LN metastasis had a decreased risk of death for each patient with LN examined up to approximately 14 LNs. Collectively, our study firmly demonstrated that the number of the retrieved LNs count was an independent prognostic factor for gastric cancer with no LN metastasis. The higher the LN count, the better the survival would be; the best CSS was observed on the LN count more than 14.

Increased number of negative lymph nodes is associated with improved survival outcome in node positive gastric cancer following radical gastrectomy

The concept of negative lymph node (NLN) counts has recently attracted attention as a prognostic indicator in various cancer. However, the correlation between NLN counts and patient prognosis in the setting of gastric cancer is not fully studied. Surveillance, Epidemiology, and End Results Program (SEER)-registered gastric cancer patients were used for analysis in this study. Clinicopathological characteristics, including race, age, gender, and tumor stage, grade, and cause specific survival were collected. Univariate and multivariate Cox proportional hazards model were used to assess the risk factors for survival. As results, X-tile plots identified 3 and 9 as the optimal cutoff value to divide the patients into high, middle and low risk subsets in terms of cause specific survival, and NLN was validated as independently prognostic factor in mulivariate Cox analysis (P < 0.001). Further analysis showed that NLN was a prognosis factor in each N stage. Collectively, our study results firmly demonstrated that the number of NLNs was an independent prognostic factor for gastric cancer patients, and together with the N stage, it could provide more accurate prognostic information than the N stage alone.

[Micrometastasis in Gastric Cancer]

Although the incidence and mortality rate of gastric cancer have been steadily declining, gastric cancer is still the fourth most common cancer in the world and more than 50% of cases occur in Eastern Asia. In Korea, gastric cancer is the second most common cancer and third cause of cancer related death. The standard surgical procedure for resectable advanced gastric cancer is D2 lymphadenectomy with radical gastrectomy. Even though R0 resection was completed, recurrence is relatively common, and contributes to the limited survival of the patients in gastric cancer. As a clinically relevant factor for detection of the recurrence, the presence of isolating tumor cells has been introduced and it is so called as 'micrometastasis'. Numerous immunohistochemistry and molecular studies have shown that micrometastasis can be demonstrated not only in lymph nodes but also in such body compartments as the bone marrow, peritoneal cavity and blood. Herein, we review the current knowledge and evidence of the prognostic significance of micrometastasis in peritoneal, lymph node, bone marrow. Also, we discuss the current state of research on the circulating tumor cell in peripheral blood.

Prognostic value of fibrosis ratio in metastatic lymph nodes of node-positive advanced gastric cancer

Lymph node metastasis plays a crucial role in predicting prognosis in advanced gastric cancer (AGC). In the present study, we formulated a fibrosis ratio (FR), defined as the number of metastatic lymph nodes with fibrosis divided by the total number of lymph nodes, and sought to determine whether it can be used to predict the prognosis of patients with AGC and improve on existing node staging. We retrospectively analyzed 161 patients who underwent curative resection for node-positive AGC between 2001 and 2010, evaluating the association between FR, lymph node ratio (LNR), and micrometastasis, and the relationship between FR and clinicopathologic findings, overall survival (OS) and disease-free survival (DFS). A high FR was significantly related to T stage (P < .001), N stage (P < .001), tumor stage (P < .001), lymphatic invasion (P < .001), and venous invasion (P = .007). FR was significantly correlated with an increased number of metastatic lymph nodes (P = .001, R = 0.869) and LNR (P = .001, R = 0.943), but not with total harvested lymph nodes. Patients with micrometastases had a lower FR, compared with those without micrometastases (P < .001). A survival analysis showed poor OS for patients in the entire cohort (P < .001); N1 (P = .002), N2 (P = .004), N3a (P = .010), and N3b (P = .003) stages; and groups with high LNR (P = .013) and low LNR (P = .001). DFS was also poor for the entire cohort (P < .001) and the N2 (P = .013), N3b (P = .002), high-LNR (P = .036), and low-LNR (P = .001) groups, but not the N1 or N3a group. Univariate and multivariate analyses revealed that high FR was an independent prognostic factor for OS (hazard ratio [HR], 2.780; CI, 1.655-4.670; P < .001) and DFS (HR, 2.051; CI, 1.199-3.508; P = .009) in AGC. Collectively, our findings indicate that high FR is associated with adverse clinicopathologic parameters in AGC, clearly establishing nodal fibrosis as a pathological finding with value in predicting poor prognosis of patients with AGC. Thus, combining current N stage and LNR diagnostics with FR could improve prognostic prediction in AGC.

Prognostic significance of the total number of harvested lymph nodes for lymph node-negative gastric cancer patients

Background

The relationship between the number of harvested lymph nodes (HLNs) and prognosis of gastric cancer patients without an involvement of lymph nodes has not been well-evaluated. The objective of this study is to further explore this issue.

Methods

We collected data from 399 gastric cancer patients between November 2006 and October 2011. All of them were without metastatic lymph nodes.

Results

Survival analyses showed that statistically significant differences existed in the survival outcomes between the two groups allocated by the total number of HLNs ranging from 16 to 22. Therefore, we adopted 22 as the cut-off value of the total number of HLNs for grouping (group A: HLNs <22; group B: HLNs≥22). The intraoperative and postoperative characteristics, including operative blood loss (P=0.096), operation time (P=0.430), postoperative hospital stay (P=0.142), complications (P=0.552), rate of reoperation (P=0.966) and postoperative mortality (P=1.000), were comparable between the two groups. T-stage-stratified Kaplan–Meier analyses revealed that the 5-year survival rate of patients at the T4 stage was better in group B than in group A (76.9% vs. 58.5%; P=0.004). An analysis of multiple factors elucidated that the total number of HLNs, T stage, operation time and age were independently correlated factors of prognosis.

Conclusions

Regarding gastric cancer patients without the involvement of lymph nodes, an HLN number ≥22 would be helpful in prolonging their overall survival, especially for those at T4 stage. The total number of HLNs was an independent prognostic factor for this population of patients.

Prognostic Factors for Survival in Node-Negative Gastric Cancer Patients Who Underwent Curative Resection

BACKGROUND AND AIM

Lymph node involvement is the strongest prognostic factor for patients with gastric cancer; patients with node-negative gastric cancer present with better survival. However, some patients develop recurrent gastric cancer. The aim of this study was to review the clinicopathological characteristics and factors for prognosis in patients with node-negative gastric cancer who underwent curative resection.

METHODS

Between January 2004 and December 2015, the clinicopathological characteristics of 302 patients with node-negative gastric cancer who underwent curative gastrectomy in our hospital were retrospectively analyzed.

RESULTS

The 1-, 3-, and 5-year overall survival rates for patients with node-negative gastric cancer were 80.0%, 69.0%, and 63.0%, respectively. Univariate analysis showed that tumor size, histologic type, and depth of invasion had significant effects on survival (p < 0.05). Multivariate analysis showed that tumor size (hazard ratio: 1.83%, 95.0% confidence interval: 1.13-2.96, p = 0.014), histologic type (hazard ratio: 1.57%, 95.0% confidence interval: 1.01-2.44, p = 0.042), and depth of invasion (hazard ratio: 1.38%, 95.0% confidence interval: 1.14-1.67, p = 0.001) were independent prognostic factors.

CONCLUSION

Tumor size, histologic type, and depth of invasion are important prognostic factors in patients with node-negative gastric cancer. These parameters should be considered to stratify patients for therapy and follow-up strategies.

Poorly Differentiated Medullary Phenotype Predicts Poor Survival in Early Lymph Node-Negative Gastro-Esophageal Adenocarcinomas

BACKGROUND

5-year survival rate in patients with early adenocarcinoma of the gastro-esophageal junction or stomach (AGE/S) in Caucasian patients is reported to be 60-80%. We aimed to identify prognostic markers for patients with UICC-I without lymph-node involvement (N0).

METHODS

Clinical data and tissue specimen from patients with AGE/S stage UICC-I-N0, treated by surgery only, were collected retrospectively. Tumor size, lymphatic vessel or vein invasion, grading, classification systems (WHO, Lauren, Ming), expression of BAX, BCL-2, CDX2, Cyclin E, E-cadherin, Ki-67, TP53, TP21, SHH, Survivin, HIF1A, TROP2 and mismatch repair deficiency were analyzed using tissue microarrays and correlated with overall and tumor related survival.

RESULTS

129 patients (48 female) with a mean follow-up of 129.1 months were identified. 5-year overall survival was 83.9%, 5-year tumor related survival was 95.1%. Poorly differentiated medullary cancer subtypes (p<0.001) and positive vein invasion (p<0.001) were identified as risk factors for decreased overall-and tumor related survival. Ki-67 (p = 0.012) and TP53 mutation (p = 0.044) were the only immunohistochemical markers associated with worse overall survival but did not reach significance for decreased tumor related survival.

CONCLUSION

In the presented study patients with AGE/S in stage UICC-I-N0 had a better prognosis as previously reported for Caucasian patients. Poorly differentiated medullary subtype was associated with reduced survival and should be considered when studying prognosis in these patients.

Occult Tumor Cells in Lymph Nodes of Patients with Gastric Cancer: A Systematic Review on Their Prevalence and Predictive Role

BACKGROUND AND AIMS

The presence of lymph node (LN) metastasis is a key prognostic factor for gastric adenocarcinoma. However, even among patients without LN metastasis (N0), recurrence may occur. In some of these cases, occult tumor cells (OTC) are thought to play an important role. We aimed to determine the prevalence of OTC and its clinical relevance.

METHODS

We conducted a systematic review of studies in English published until September 2013 that addressed OTC prevalence and/or its clinical relevance. The studies were retrieved from the MEDLINE database.

RESULTS

We included 42 studies. The most frequently used methods for detecting OTC were immunohistochemical examination (IHC) and/or polymerase chain reaction (PCR) with a wide range of markers. Using IHC for OTC detection, in patients and in LN, the prevalence varied from 9 to 88% and 0.4 to 42%, respectively. With PCR, it ranged from 17 to 46% in patients, and from 3 to 33% in LN. In the studies assessing the predictive role of OTC in gastric cancer recurrence (n=24), 8 studies found no statistical association, while 18 concluded that OTC presence was associated with poorer prognosis. However, only 6 studies presented a significantly different 5-year survival rate between patients with and without LN micrometastasis.

CONCLUSIONS

OTC seems to occur in gastric cancer patients with a variable prevalence, depending on the definition, methods and setting. The majority of the retrieved studies (75%) evaluating the predictive role of OTC conclude that its presence is associated with a worse prognosis.

Antitumor and antimetastatic effects of pemetrexed-loaded targeted nanoparticles in B16 bearing mice

Using nanoparticle delivery for anticancer therapy is a potential new drug modality. We developed a novel gelatinase-stimuli nanoparticle. In this study, we studied the antitumor and antimetastasis effect of pemetrexed-loaded targeted nanoparticles and evaluated the correlation between E-cadherin expression and lung metastasis in subcutaneous xenograft model. Compared with free pemetrexed, pemetrexed-loaded targeted nanoparticles exhibited the best antitumor and antimetastasis efficacy among the four therapeutic groups. The study also indicated that there was an inverse correlation between lung metastasis and E-cadherin expression. These results showed pemetrexed-loaded targeted nanoparticles may be a potent drug for tumor therapy and our preclinical data could provide new direction for clinical therapy of malignant melanoma.

Current status and scope of lymph node micrometastasis in gastric cancer

Recently, lymph node micrometastasis has been evaluated for its prognostic value in gastric cancer. Lymph node micrometastasis cannot be detected via a usual pathologic examination, but it can be detected by using some other techniques including immunohistochemistry and reverse transcription-polymerase chain reaction assay. With the development of such diagnostic techniques, the detection rate of lymph node micrometastasis is constantly increasing. Although the prognostic value of lymph node micrometastasis remains debatable, its clinical impact is apparently remarkable in both early and advanced gastric cancer. At present, studies on the prognostic value of lymph node micrometastasis are evolving to overcome its current limitations and extend the scope of its application.

Gastric carcinoma: stage migration by immunohistochemically detected lymph node micrometastases

BACKGROUND

Immunohistochemically detected micrometastases of the regional lymph nodes in previously pN0-classified gastric cancer have been incorporated in the TNM staging system. This study aims to determine the incidence of such micrometastases in gastric carcinoma and to investigate their impact on stage grouping and prognosis.

METHODS

Ninety-five patients with gastric carcinoma classified as pN0 by conventional histological examination were enrolled. All patients underwent gastric resection with regional lymphadenectomy between 2006 and 2010. A total of 2018 lymph nodes was obtained (median, 20 Lymph nodes) and immunohistostained with anti-pan cytokeratin antibody (KL1).

RESULTS

Micrometastases were detected in regional lymph nodes by immunohistostaining in 16 out of all 95 patients. Fourteen patients were upstaged by micrometastasis-positive regional lymph nodes. Three patients demonstrated lymph nodes with isolated tumor cells alone. A significantly higher incidence of micrometastases was observed in patients with diffuse histologic type (p = 0.007) and total gastrectomy (p = 0.007). When isolated tumor cells were also regarded as lymph node involvement, the recurrence rate was significantly higher for node-positive than for node-negative patients and for those younger than 70 years (33.3 and 6.7 %, respectively; p = 0.026; n = 39). Overall survival analysis revealed no significant difference between micrometastasis-positive and micrometastasis-negative patients.

CONCLUSION

Immunohistostaining of regional lymph nodes in node-negative gastric carcinoma patients leads to an increased detection of micrometastases with significant implications for the staging system. Although no impact on survival time was shown, the higher recurrence rate for node-positive patients younger than 70 years indicates a prognostic value of immunohistochemically detectable micrometastases.

Clinical significance of molecular diagnosis for gastric cancer lymph node micrometastasis

Advances in molecular diagnostic tools have allowed the identification of lymph node micrometastasis (LNM), including isolated tumor cells, in cancer patients. While immunohistochemistry and reverse transcription-polymerase chain reaction have been used to identify LNM in patients with gastric cancer, the clinical significance of this finding remains unclear. Recently, minimally invasive treatments, such as endoscopic submucosal dissection and laparoscopic surgery, are widely performed to help improve postsurgical quality of life (QOL). However, it is important to maintain the balance between QOL and curability when making treatments decision for patients with gastric cancer. If minimally invasive surgery based on accurate intraoperative LNM diagnosis was established, it could be performed safely. Therefore, we reviewed the clinical significance of LNM detected by molecular techniques as an important target for treatment decision making with gastric cancer patients.

Methylation-mediated gene silencing as biomarkers of gastric cancer: A review

Despite a decline in the overall incidence of gastric cancer (GC), the disease remains the second most common cause of cancer-related death worldwide and is thus a significant global health problem. The best means of improving the survival of GC patients is to screen for and treat early lesions. However, GC is often diagnosed at an advanced stage and is associated with a poor prognosis. Current diagnostic and therapeutic strategies have not been successful in decreasing the global burden of the disease; therefore, the identification of reliable biomarkers for an early diagnosis, predictive markers of recurrence and survival and markers of drug sensitivity and/or resistance is urgently needed. The initiation and progression of GC depends not only on genetic alterations but also epigenetic changes, such as DNA methylation and histone modification. Aberrant DNA methylation is the most well-defined epigenetic change in human cancers and is associated with inappropriate gene silencing. Therefore, an increasing number of genes methylated at the promoter region have been targeted as possible biomarkers for different purposes, including early detection, classification, the assessment of the tumor prognosis, the development of therapeutic strategies and patient follow-up. This review article summarizes the current understanding and recent evidence regarding DNA methylation markers in GC with a focus on the clinical potential of these markers.

Should lymph node micrometastasis be considered in node staging for gastric cancer?: the significance of lymph node micrometastasis in gastric cancer

BACKGROUND

In TNM staging system, lymph node staging is based on the number of metastatic lymph nodes in gastric cancer and micrometastasis is not considered. Several reports proposed the importance of lymph node micrometastasis as the causative factor for recurrence and poor survival, but it remains controversial among researchers.

METHODS

A total of 482 gastric cancer patients who underwent curative resection from 2004 to 2010 at Korea University Medical Center Ansan Hospital, South Korea were prospectively enrolled. For detecting lymph node micrometastasis, immunohistochemical staining with anti-cytokeratin antibody (CAM 5.2) was performed on negative lymph nodes by hematoxylin-eosin (H-E) staining. Survival differences were compared between conventional node staging and new node staging that took micrometastasis into consideration. Also, the prognostic value of lymph node micrometastasis was investigated in multivariate analysis.

RESULTS

A total of 156 patients (32.4%) showed lymph node micrometastasis. Overall, the micrometastatic group had more advanced tumor and lymph node stage, lymphovascular cancer cell invasion, a higher rate of recurrence, and poor survival. Furthermore, when the cumulative numbers of macro- and micrometastatic lymph nodes were calculated together, the discriminative power of survival difference between each node stage became more stratified. Also, multivariate analysis using Cox's proportional hazards model demonstrated perineural invasion, pathologic T stage, dissected lymph nodes, macro- and micrometastatic lymph nodes are independent prognostic factors.

CONCLUSIONS

Lymph node micrometastasis was clinically significant as a risk factor for recurrent gastric cancer. Lymph node micrometastasis should be considered when estimating TNM stage for determining prognosis and the best treatment strategy.

Does the retrieval of at least 15 lymph nodes confer an improved survival in patients with advanced gastric cancer?

PURPOSE

The standard surgical procedure recommended to treat gastric cancer in advanced cases is dissection of D2 lymph nodes (LNs). However, the optimum number of LNs that should be retrieved in advanced gastric cancer (AGC) remains debatable. Therefore, this study aimed to investigate the optimum number of retrieved LNs and determine the clinical implications of retrieved LN numbers on the treatment of AGC.

MATERIALS AND METHODS

Of 575 AGC patients reviewed, 369 who underwent open curative gastrectomy with D2 or more extensive LN dissection at our institution were analyzed according to their clinicopathologic characteristics and number of LNs retrieved.

RESULTS

Multivariate regression analysis revealed that tumor size (P=0.006), depth of invasion (P=0.000), LN metastasis (P=0.000), and stage (P=0.000) were independent variables with predictive value. The 5-year survival rates were differed significantly according to the numbers of LNs retrieved ([1] 15~25 vs. >25 and [2] 15~39 vs. ≥40) in patients with differentiated carcinoma.

CONCLUSIONS

Tumor size, depth of invasion, LN metastasis, and stage were independent predictive factors for survival. The number of retrieved LNs was significantly associated with a long-term survival benefit in patients with differentiated carcinoma. Therefore, our data suggest that the retrieval of a minimum of 15 LNs may not be sufficient to warrant a recommendation for further curative surgery and that extensive LN dissection should be considered in advanced carcinoma of the differentiated type.

CD44(+) CD324(-) expression and prognosis in gastric cancer patients

PURPOSE

To evaluate the frequency of cancer stem cell marker CD44 combined CD324 expression in gastric cancer specimens and association of the expression with survival of gastric cancer patients.

METHODS

A total of 203 patients with primary gastric cancer who underwent curative gastric resection with lymphadenectomy were studied. The expression of CD44 and CD324 was analyzed by immunohistochemistry and the association of CD44 and CD324 expression analyzed by clinicopathological characteristics. Survival of the patients was evaluated.

RESULTS

CD44(+) CD324(-) tumors showed strong correlation with positive lymph node metastasis. Patients with CD44(-) CD324(+) had a significantly better prognosis (54.8%) than that with CD44(+) CD324(-) (24.5%). A multivariate Cox proportional hazards model using those variables associated with survival in our study (depth of invasion, tumor size, lymph node metastasis, gastrectomy, CD44 expression, CD324 expression, CD44 and CD324 expression) revealed that CD44(+) CD324(-) expression (P = 0.005) was one of significant independent prognostic indicator, whereas CD44 expression (P = 0.081), CD324 expression (P = 0.068) was not.

CONCLUSION

CD44(+) CD324(-) expression was one of significant independent prognostic survival factors for patients with gastric cancer.

Prognostic value of number of examined lymph nodes in patients with node-negative gastric cancer

AIM: To elucidate the potential impact of examined lymph nodes (eLNs) on long-term survival of node-negative gastric cancer patients after curative surgery.

METHODS: A total of 497 node-negative gastric cancer patients who underwent curative gastrectomy between January 2000 and December 2008 in our center were enrolled in this study. Patients were divided into 4 groups according to eLNs through cut-point analysis. Clinicopathological features were compared between ≤ 15 eLNs group and > 15 eLNs group and potential prognostic factors were analyzed. The Log-rank test was used to assess statistical differences between the groups. Independent prognostic factors were identified using the Cox proportional hazards regression model. Stratified analysis was performed to investigate the impact of eLNs on patient survival in each stage. Overall survival was also compared among the four groups. Finally, we explored the recurrent sites associated with eLNs.

RESULTS: Patients with eLNs > 15 had a better survival compared with those with eLNs ≤ 15 for the entire cohort. By the multivariate survival analysis, we found that the depth of invasion and the number of eLNs were the independent predictors of overall survival (OS) of patients with node-negative gastric cancer. According to the cut-point analysis, T2-T4 patients with 11-15 eLNs had a significantly longer mean OS than those with 4-10 eLNs or 1-3 eLNs. Patients with ≤ 15 eLNs were more likely to experience locoregional and peritoneal recurrence than those with > 15eLNs.

CONCLUSION: Number of eLNs could predict the prognosis of node-negative gastric cancer, and dissection of > 15 eLNs is recommended during lymphadenectomy so as to improve the long-term survival.

Negative node count improvement prognostic prediction of the seventh edition of the TNM classification for gastric cancer

OBJECTIVE

To demonstrate that the seventh edition of the tumor-node-metastasis (TNM) classification for gastric cancer (GC) should be updated with the number of negative lymph nodes for the improvement of its prognostic prediction accuracy.

METHODS

Clinicopathological data of 769 GC patients who underwent curative gastrectomy with lymphadenectomy between 1997 and 2006 were retrospectively analyzed to demonstrate the superiority of prognostic efficiency of the seventh edition of the TNM classification, which can be improved by combining the number of negative lymph nodes.

RESULTS

With the Cox regression multivariate analysis, the seventh edition of the TNM classification, the number of negative nodes, the type of gastrectomy, and the depth of tumor invasion (T stage) were identified as independent factors for predicting the overall survival of GC patients. Furthermore, we confirmed that the T stage-N stage-number of negative lymph nodes-metastasis (TNnM) classification is the most appropriate prognostic predictor of GC patients by using case-control matched fashion and multinominal logistic regression. Finally, we were able to clarify that TNnM classification may provide more precise survival differences among the different TNM sub-stages of GC by using the measure of agreement (Kappa coefficient), the McNemar value, the Akaike information criterion, and the Bayesian Information Criterion compared with the seventh edition of the TNM classification.

CONCLUSION

The number of negative nodes, as an important prognostic predictor of GC, can improve the prognostic prediction efficiency of the seventh edition of the TNM classification for GC, which should be recommended for conventional clinical applications.

The prognostic impact of occult lymph node metastasis in node-negative gastric cancer: a systematic review and meta-analysis

PURPOSE

To conduct a meta-analysis to clarify whether occult lymph node metastasis (OLNM), which is identified by molecular detection techniques but is not detected by routine histological examination within regional lymph nodes, represents a prognostic factor for patients with node-negative gastric cancer.

METHODS

PubMed, Embase, and the Cochrane Library were searched from their inception to November 2012. The published studies that investigated the association between OLNM and the prognosis of patients with node-negative gastric cancer were included. We extracted hazard ratios (HRs) and associated standard errors from the identified studies and performed random-effects model meta-analyses on overall survival and disease-specific survival. Subgroup analyses were also conducted.

RESULTS

A total of 14 eligible studies that included 1,478 patients were identified. Meta-analyses revealed that OLNM was associated with poor overall survival [HR 2.72; 95% confidence interval (CI) 1.61-4.60], and disease-specific survival (HR 2.91; 95% CI 1.25-6.79). Subgroup analyses suggested that OLNM was associated with poor survival in early gastric cancer (HR 3.57; 95% CI 1.23-10.33). However, subgroup analyses of studies that exclusively enrolled patients with D2 lymph node dissection demonstrated that OLNM did not have an influence on the prognosis (HR 1.97; 95% CI 0.82-4.70).

CONCLUSIONS

OLNM correlates with poor prognosis for patients with node-negative gastric cancer, and D2 lymph node dissection could eliminate this correlation. For OLNM-positive patients with node-negative gastric cancer, D2 lymph node dissection is necessary.

Lymph node micrometastasis in gastrointestinal tract cancer--a clinical aspect

Lymph node micrometastasis (LNM) can now be detected thanks to the development of various biological methods such as immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Although several reports have examined LNM in various carcinomas, including gastrointestinal (GI) cancer, the clinical significance of LNM remains controversial. Clinically, the presence of LNM is particularly important in patients without nodal metastasis on routine histological examination (pN0), because patients with pN0 but with LNM already in fact have metastatic potential. However, at present, several technical obstacles are impeding the detection of LNM using methods such as IHC or RT-PCR. Accurate evaluation should be carried out using the same antibody or primer and the same technique in a large number of patients. The clinical importance of the difference between LNM and isolated tumor cells (≤0.2 mm in diameter) will also be gradually clarified. It is important that the results of basic studies on LNM are prospectively introduced into the clinical field. Rapid diagnosis of LNM using IHC and RT-PCR during surgery would be clinically useful. Currently, minimally invasive treatments such as endoscopic submucosal dissection and laparoscopic surgery with individualized lymphadenectomy are increasingly being performed. Accurate diagnosis of LNM would clarify issues of curability and safety when performing such treatments. In the near future, individualized lymphadenectomy will develop based on the establishment of rapid, accurate diagnosis of LNM.

Cadherin-17 induces tumorigenesis and lymphatic metastasis in gastric cancer through activation of NFκB signaling pathway

Cadherin-17 (CDH17), as a structurally unique member of the cadherin superfamily, has been identified to predict a poor prognosis for gastric cancer (GC). Our previous study demonstrated the positive correlation between CDH17 and lymph node micrometastasis in GC. We sought to further identify the role of CDH17 in the tumorigenesis and lymphatic metastasis of GC. Hence, we inhibited the CDH17 expression in MKN-45 gastric cancer cells by using RNA interference. Consequently, the malignant potency of cancer cells was evaluated, and the change in NFκB signaling pathway was also probed. Tumor growth and lymphatic metastasis model were conducted in nude mice to confirm the hypothesis. Downregulation of CDH17 not only suppressed the proliferation, adherence and invasion potency of MKN-45 cells, but also induced cell cycle arrest. Meanwhile, the NFκB signaling pathway was inactivated as well, with the reductions of downstream proteins including VEGF-C and MMP-9. Moreover, silencing CDH17 inhibited tumor growth in vivo significantly, and there was no lymph node metastasis detected in the mice without CDH17 expression, as opposed to the positive nodes found in controls. CDH17 is a novel oncogene in gastric cancer cells, which is associated with lymphatic metastasis and proliferation strongly. The inactivation of NFκB signaling pathway might be involved in targeting CDH17 in GC. On the whole, CDH17 is proposed to serve as a biomarker and attractive therapeutic target in GC.

Perigastric tumor deposits in primary gastric cancer: implications for patient prognosis and staging

BACKGROUND

Metastatic nodules in perigastric adipose tissue without evidence of lymph node tissue have been reported in gastric cancers. However, the morphological features and clinical significance of perigastric tumor deposits (TD) have not been clarified in gastric cancers.

METHODS

To demonstrate the clinical implication of perigastric TD, 653 consecutive gastric cancer patients were enrolled and all of their slides were reviewed. Separate tumor nodules in the perigastric fat were classified as perigastric TD and correlated with clinicopathologic features and patient survival.

RESULTS

Perigastric TD were observed in 156 (23.9 %) of 653 patients. Perigastric TD were associated with synchronous distant metastasis (p < 0.001), independently of depth and venous invasion. There was a significant difference between the overall survival of those with and without TD by univariate (p < 0.001) and multivariate (p = 0.001) survival analyses. However, distant metastasis or patient prognosis could not be predicted by the morphologic patterns of the TD (p > 0.05). When TD without lymph node tissue and lymph node metastasis were recorded separately, TD were observed in 13 node-negative patients. The overall survival of node-negative patients with TD was significantly worse than that of node-negative patients without TD (p < 0.001).

CONCLUSIONS

Perigastric TD significantly correlated with distant metastasis and satisfactorily predicted patient outcomes independently of invasion depth, lymph node metastasis, and other clinicopathologic factors. Our findings suggest that perigastric TD should be included in the staging of patients with gastric cancer.

Prognostic factors and recurrence pattern in node-negative advanced gastric cancer

AIMS

Despite better overall survival in node-negative advanced gastric cancer (AGC), a significant proportion of patients develop recurrence and they may benefit from adjuvant therapy. The aim of this study was to evaluate the prognostic factors and recurrence pattern of node-negative AGC.

METHODS

A total of 424 patients who underwent curative gastrectomy with extended lymphadenectomy for node-negative AGC between 2003 and 2005 were retrospectively reviewed. Patients with tumor involvement of adjacent organs (T4b), gastric cancer recurrence, tumor in the remnant stomach, less than 15 harvested lymph nodes, and those who received neoadjuvant chemotherapy were excluded.

RESULTS

Invasion to deeper layers, undifferentiated histology, signet ring cell type compared with tubular adenocarcinoma, and tumor size larger than 6.3 cm correlated with poorer prognosis in univariate analysis. In multivariate one, however, only differentiation and depth of invasion, especially the presence of serosa involvement were significant. The 5-year survival rates of the four groups classified by differentiation and depth of invasion [T2/3 (differentiated type), T2/3 (undifferentiated type), T4a (differentiated type), and T4a (undifferentiated type)] were 98%, 92%, 80%, and 72%, respectively (P < 0.01). In terms of recurrence pattern, Lauren's type and depth of invasion were significant. Recurrence with peritoneal seeding was associated with the diffuse type and invasion into the subserosa or serosa, while hematogenous metastasis was related to the intestinal type and invasion to the proper muscle or subserosa layer.

CONCLUSIONS

Differentiation and serosa involvement should be considered to stratify patients with node-negative AGC for adjuvant treatment.

Effect of lymph node number on survival of patients with lymph node-negative gastric cancer according to the 7th edition UICC TNM system

BACKGROUND

For the patients with node-negative gastric cancer, the 7th edition classification does not define the minimum number of lymph nodes necessary. We aimed to explore the prognostic significance of examined lymph nodes and determine how many nodes must be examined.

METHODOLOGY/PRINCIPAL FINDINGS

435 patients underwent D2 gastrectomy with node-negative gastric cancer between December 1992 and December 2006 were obtained. Patients were classified into 4 groups by the number of negative LNs examined during surgery (1-6LNs, 7-10 LNs, 11-15 LNs, and > = 16 LNs). Stratified and Cox regression analyses were used to evaluate the association between survival and the number of negative LNs. Survival was significantly better in the > = 16 LNs, compared with the 1-5 LNs, 6-10 LNs and 11-15 LNs group in T2-4 patients; Multivariate analysis demonstrated tumor size, depth of invasion, 7th UICC stage and the number of examined nodes are strongly independent predictors of survival.

CONCLUSIONS

This study first demonstrates that patients with lymph node-negative gastric cancer underwent D2 dissection should have at least 16 LNs examined, especially in advanced gastric cancer. These results are a reasonable supplement to our previous tumor-ratio-metastasis staging system and a stratification criterion in clinical practice.

Clinical significance of lymph node micrometastasis in gastric cancer

Recently, the existence of lymph node micrometastasis (LNM), including isolated tumor cells, has been focused on during the development of molecular diagnostic tools for lymph node metastasis in various malignant neoplasms. In particular, immunohistochemistry and reverse transcription-polymerase chain reaction have been reported to be available for the detection of LNM in gastric cancer. However, at present, the clinical significance of LNM remains unclear in patients with gastric cancer. Therefore, we cannot strategically make light of this issue in clinical management. Currently, minimally invasive treatments, such as endoscopic submucosal dissection and laparoscopic surgery with personalized lymphadenectomy, are widely performed in consideration of postsurgical quality of life (QOL). However, it is important to maintain the balance between QOL and curability when selecting surgical treatments for patients with gastric cancer. If minimally invasive surgery based on LNM status was established for patients with early gastric cancer, it could be performed safely. We reviewed the clinical significance of LNM as an important strategic target in patients with gastric cancer.

The predictive effect of cadherin-17 on lymph node micrometastasis in pN0 gastric cancer

BACKGROUND

Previous studies identified cadherin-17 (CDH17) as one of the most upregulated genes in node-positive gastric cancer. However, the prognostic significance of CDH17 in pN0 gastric cancer and its association with lymph node micrometastasis (LNMM) have not been investigated.

METHODS

Clinicopathologic features of 191 patients with node-negative gastric cancer were studied retrospectively. All dissected lymph nodes were immunostained by cytokeratin to detect micrometastasis. CDH17 and lymphatic invasion (LVI) in primary carcinoma were evaluated by immunostaining of monoclonal CDH17 and D2-40 antibody. Correlation of CDH17 with clinicopathologic characteristics was subsequently assessed. Risk factors of LNMM were analyzed by univariate and multivariate logistic regression. Cox's proportional hazard model was applied to investigate independent prognostic factors of pN0 gastric cancer. Overall survival rates of patients with positive and negative CDH17 were compared, stratifying by pT stage, Lauren grade, and LNMM status.

RESULTS

CDH17 was observed in 126 patients (66.0%). Positive expression of CDH17 was significantly associated with the age, tumor size, pT, Lauren grade, LVI, and LNMM, and identified as one of the independent risk factors of LNMM. Negative predictors of pN0 gastric cancer included pT, Lauren grade, LNMM, and CDH17. Furthermore, in tumors of pT2-3, intestinal histotype, and negative-LNMM, the survival rate of patients with CDH17 was significantly lower than that of patients without CDH17.

CONCLUSIONS

CDH17 was positively associated with larger tumor size, deeper invasion, diffuse/mixed histotype, LVI, and LNMM, predicting a poor prognosis in pN0 gastric cancer. Additionally, CDH17 may also serve as a potential indicator of LNMM.

Prognostic significance of intraoperative chemotherapy and extensive lymphadenectomy in patients with node-negative gastric cancer

BACKGROUND AND OBJECTIVES

Despite a relatively better prognosis, patients with node-negative gastric cancer still suffer from metastasis and recurrence. To investigae the prognostic factors and appropriate therapies for these pN0 tumors, we analyzed the predictors and evaluated the impact of chemotherapy and extensive lymphadenectomy on survival.

METHODS

Clinicopathologic features of 153 patients with pN0 gastric cancer were studied retrospectively. The prognostic factors were analyzed stratifying by pT1 and pT2-3 stage. The 5-year survival rate (5-YSR) of patients in different groups of chemotherapy and lymph nodes retrieved were compared.

RESULTS

Multivariate analysis indicated pT, number of nodes retrieved, and chemotherapy as the independent predictors of advanced gastric cancer; anemia was the only independent predictor of early gastric cancer. Survival of patients with pT3 got improved significantly by intraoperative chemotherapy and retrieval of more than 25 nodes, but neither of them benefited patients with pT1-2. Moreover, in pT3 status, 5-YSR of patients with intraoperative chemotherapy was still poorer than those with postoperative chemotherapy and combined chemotherapy.

CONCLUSIONS

In pN0 gastric cancers, prognostic factors differed significantly between early stage and advanced stage. For patients with pT3, besides curative gastrectomy and postoperative chemotherapy, it might be beneficial to perform intraoperative chemotherapy and extensive lymphadenectomy.

SIRT1 RNAi knockdown induces apoptosis and senescence, inhibits invasion and enhances chemosensitivity in pancreatic cancer cells

The NAD(+)-dependent deacetylase, sirtuin 1 (SIRT1), has been recently been suspected to have a role in tumorigenesis. We investigated the expression of SIRT1 in pancreatic cancer and the effect of SIRT1-targeted RNA interference (RNAi) on cell proliferation and tumor formation in a pancreatic cancer cell line, PANC1. The expression of SIRT1 was investigated in 49 specimens of pancreatic cancer and adjacent normal pancreatic tissues. SIRT1 was overexpressed in pancreatic cancer tissues at both the mRNA and protein levels, with increased SIRT1 positivity associated with tumors from patients over 60 years old, tumors larger than 4 cm, higher TNM (extent of tumor (T), the extent of spread to lymph nodes (N), and presence of distant metastasis (M)) stage or the presence of lymph node or hepatic metastases. The PANC-1 was stably transfected with a SIRT1 small hairpin RNA (shRNA) expression plasmid and compared with untransfected and PANC-1-negative RNAi cells. Proliferation of PANC-1-SIRT1-RNAi cells was significantly reduced, accompanied by increased rates of apoptosis, G1 arrest and senescence. Furthermore, FOXO3a expression was markedly upregulated in PANC-1-SIRT1-RNAi cells, but no significant difference in p53 expression was observed. The invasive ability of PANC-1-SIRT1-RNAi cells was markedly reduced in vitro, which was linked to increased E-cadherin and reduced-MMP expression. Additionally, PANC-1-SIRT1-RNAi cells had a significantly reduced capacity to form tumors in vivo compared with untransfected and PANC-1-negative RNAi cells. These results suggest that SIRT1 may promote cell proliferation and tumor formation in pancreatic cancer, and downregulation of SIRT1 using shRNA could provide a novel therapeutic treatment.

Prognostic factors in patients with node-negative gastric cancer: an Indian experience

Background

The status of the regional nodes is the most important prognostic factor in gastric cancer. There are subgroups of patients with different prognosis even in node-negative patients of gastric cancer. The aim of this study is to analyze the factors influencing the prognosis in Indian patients with node-negative gastric cancer.

Methods

This was a retrospective analysis of patients who underwent radical gastrectomy in a tertiary cancer centre in India between1991 and 2007. The study group included only patients with histologically node-negative disease. Various clinical, pathological and treatment related factors in this group of patients were analyzed to determine their prognostic ability by univariate and multivariate analyses.

Results

Among the 417 patients who underwent gastrectomy during this period, 122 patients had node-negative disease. A major proportion of the patients had advanced gastric cancer. The 5-year overall survival and disease-free survival in all node-negative gastric cancer patients was 68.2% and 67.5% respectively. The overall recurrence rate in this group was 27.3%. On univariate analysis, the factors found to significantly influence the disease-free survival were the size, location and presence or absence of serosal invasion of the primary tumor. However, on multivariate analysis, only tumor size more than 3 cm and serosal invasion were found to be independently associated with an inferior survival.

Conclusion

Serosal invasion and primary tumor size more than 3 cm independently predict a poor outcome in patients with node-negative gastric cancer.

Adverse prognosis of clustered-cell versus single-cell micrometastases in pN0 early gastric cancer

BACKGROUND AND OBJECTIVES

The clinical significance of lymph node micrometastasis (MM) for pN0 early gastric cancer is not well documented. The aim of this study is to clarify the risk factors of lymph node MM and the prognostic significance of the type of lymph node MM in patients with pN0 early gastric cancer.

METHODS

We investigated the lymph node MM with using an anticytokeratin immunohistochemical stain in 160 patients with pN0 early gastric cancer who underwent curative resection between 2000 and 2005.

RESULTS

We identified lymph node MM in 34 of 160 patients (21.3%), and in 84 of 1,656 lymph nodes (5.1%). MM occurred as single-cell type in 10 patients and as cell cluster type in 24 patients. MM was significantly associated with tumor size (P = 0.041) and lymphatic invasion (P = 0.008). The statistically significant prognostic factors affecting 5-year survival rates were depth of tumor invasion (P = 0.020), tumor size (P = 0.035), lymphatic invasion (P = 0.018), MM (P < 0.001), and type of MM (P < 0.001). Cox regression survival analysis revealed that the presence of MM, and particularly the cluster-type MM (P < 0.001), were independent prognostic factors in pN0 early gastric cancer patients.

CONCLUSIONS

The incidence of lymph node MM in patients with node negative early gastric cancer was 21.3%, and cancer cell cluster type of MM proved a primary independent prognostic factor for pN0 early gastric cancer patients.

A multicentric Western analysis of prognostic factors in advanced, node-negative gastric cancer patients

BACKGROUND

The presence of lymph node metastasis is one of the most important prognostic factors in patients with gastric carcinoma. Node-negative patients have a better outcome, nevertheless a subgroup of them experience disease recurrence.

AIM

To analyze the clinicopathological characteristics of lymph node-negative advanced gastric carcinoma patients submitted to gastrectomy and D2 lymphadenectomy with a retrieved number of nodes greater than 15, after an actual follow-up of almost 5 years, and to evaluate outcome indicators.

STUDY DESIGN

The records of 301 patients who underwent curative gastrectomy for gastric carcinoma and were adequately staged as N0 between 1992 and 2002 were retrospectively analyzed from the prospectively collected database of 7 centers participating to the Italian Research Group for Gastric Cancer.

RESULTS

Disease-specific and disease-free survival after 3, 5, and 10 years were 90.4%, 86.1%, 75.9%, and 72.1%, 57.3%, 57.3%, respectively. Mortality was 1.7%. The factors associated with a better disease-free survival at univariate analysis were age <60, T2 tumors, distal location, intestinal histotype, and number of retrieved nodes >25; depth of infiltration and histotype were the only 2 independent predictors of 5-year recurrence-free survival at multivariate analysis.

CONCLUSION

These parameters must be considered to stratify node-negative gastric cancer patients for an adjuvant treatment and follow-up scheduling. Survival was similar to that previously reported by Eastern Centers. Lymphadenectomy is suggested to be effective, and retrieval of more than 25 nodes may be warranted.

Prognostic significance of E-cadherin expression and peripheral blood micrometastasis in gastric carcinoma patients

BACKGROUND

The primary objective is to evaluate the prognostic value of E-cadherin (E-cad) expression and peripheral blood micrometastasis (PBMM) in gastric carcinoma. Secondary objective is to study the association between these 2 markers and the clinicopathological features of the patients.

MATERIALS AND METHODS

This study took place at Ain Shams University Hospitals. A total of 30 patients with histologically proven gastric adenocarcinoma after curative surgical resection were enrolled in this study. E-cad expression was assessed in tumor tissue samples. Before the start of adjuvant chemoradiotherapy, fresh blood samples were collected to detect PBMM as indicated by cytokeratin18 mRNA expression using real-time quantitative polymerase chain reaction (RQ-PCR).

RESULTS

Both abnormal E-cad expression and PBMM were significantly associated with lymph node metastasis, TNM stage, and lymphatic invasion. Moreover, PBMM was significantly associated with poor tissue differentiation and vascular invasion (P < .05). We found strong agreement between E-cad expression and presence of PBMM (P = .001). Both cases with altered E-cad expression and cases with positive PPMM showed shorter relapse-free survival (RFS) (P = .003 and <.001, respectively). Cox regression analysis showed that positive PBMM was independent predictor factor for relapse (hazard ratio [HR] = 6.14; 95% confidence interval [95% CI] = 1.06-35.63; P = .04). Cases with positive PBMM showed shorter overall survival (OS) (P = .001).

CONCLUSIONS

In conclusion, loss of normal E-cad expression in gastric cancer showed a close correlation with the presence of PBMM. PBMM was associated with poor RFS independent of other clinicopathological features. Additionally, detection of PBMM was a significant indicator of OS, and intensive chemotherapy seems to be indicated for these patients.

Aberrant gene methylation in the lymph nodes provides a possible marker for diagnosing micrometastasis in gastric cancer

BACKGROUND

This study was designed to determine whether gene methylation is a novel diagnostic marker for micrometastasis to the lymph nodes (LNs) in gastric cancer.

METHODS

The gene methylation of CHFR, p16, RUNX3, E-cadherin, MGMT, hMLH1, and ABCG2 genes were analyzed in 49 primary gastric cancer tissues, corresponding to noncancerous tissues and matched LNs by quantitative methylation-specific PCR (q-MSP).

RESULTS

CHFR, RUNX3, MGMT, and hMLH1 were more frequently methylated in primary cancer compared with the noncancerous mucosa. Further analyses investigated whether the methylation of the four cancer-specific genes was preserved in LN tissues using the 29 control cases, in which LN metastasis had been histologically confirmed. The methylation of both lesions (M/M pattern) in at least one gene, which was judged to be positive for cancer cells in LNs, was observed in 25 of 29 cases (86%). Quantitative RT-PCR (qRT-PCR) of CEA, CK19, and CK20 mRNA was conducted using the same samples. The mRNA expression of at least one of the three genes was observed in 100% of the specimens. The results of the control analysis were used to attempt to predict micrometastasis by q-MSP and qRT-PCR in the 20 test cases without histological LN metastasis. Six cases (30%) showed the M/M pattern in at least one of the four genes. Three of 20 cases (15%) exhibited both the M/M pattern and positive mRNA.

CONCLUSIONS

The methylation analysis revealed the clinical feasibility of detecting occult neoplastic cells in the regional LNs.

Routine modified D2 lymphadenectomy performance in pT1-T2N0 gastric cancer

AIM: To evaluate routine modified D2 lymphadenectomy in gastric cancer, based on immunohistochemically detected skip micrometastases in level II lymph nodes.

METHODS: Among 95 gastric cancer patients who were routinely submitted to curative modified D2 lymphadenectomy, from January 2004 to December 2008, 32 were classified as pN0. All level I lymph nodes of these 32 patients were submitted to immunohistochemistry for micrometastases detection. Patients in whom micrometastases were detected in the level I lymph node stations (n = 4) were excluded from further analysis. The level II lymph nodes of the remaining 28 patients were studied immunohistochemically for micrometastases detection and constitute the material of the present study.

RESULTS: Skip micrometastases in the level II lymph nodes were detected in 14% (4 out of 28) of the patients. The incidence was further increased to 17% (4 out of 24) in the subgroup of T1-2 gastric cancer patients. All micrometastases were detected in the No. 7 lymph node station. Thus, the disease was upstaged from stage IA to IB in one patient and from stage IB to II in three patients.

CONCLUSION: In gastric cancer, true R0 resection may not be achieved without modified D2 lymphadenectomy. Until D2+/D3 lymphadenectomy becomes standard, modified D2 lymphadenectomy should be performed routinely.

Clinical significance of immunohistochemically-identified lymphatic and/or blood vessel tumor invasion in gastric cancer

BACKGROUND

Tumor invasion and lymph node metastasis are significant prognostic factors for gastric cancer, and lymphatic and vascular tumor invasion are also significant risk factors for gastric cancer recurrence. Recently, the immunohistochemical detection of lymphatic and blood vessel tumor invasion (LBVI) has been shown to have a higher sensitivity and specificity than hematoxylin-eosin staining methods.

MATERIALS AND METHODS

One hundred forty-nine gastric cancer patients who underwent curative resection at Korea University Hospital between November 2003 and December 2006 served as the study subjects. Lymphatic vessel invasion was evaluated by immunostaining with the new selective marker, D2-40, and blood vessel invasion was assessed with anti-CD31 antibody. Patients were divided according to the presence of LBVI, clinicopathologic factors were compared, and postoperative surgical outcomes were analyzed.

RESULTS

LBVI was present in 66 patients (44.3%). LBVI was significantly correlated with depth of tumor invasion (P < 0.001), lymph node stage (P < 0.001), and lymph node micrometastasis (P = 0.013). Cancer recurrence was more common in the LBVI group (P = 0.007), and peritoneal seeding was the most prevalent type of recurrence (P = 0.028). Univariate analysis showed tumor size, depth of tumor invasion, lymph node stage, and LBVI to have a significant impact on survival. Based on multivariate analysis, however, depth of tumor invasion and lymph node stage were correlated with survival.

CONCLUSION

Immunohistochemical demonstration of LBVI is an additional prognostic marker, and provides useful information for planning treatment strategies in gastric cancer patients.

Methylene blue-assisted lymph node dissection in combination with ex vivo sentinel lymph node mapping in gastric cancer

AIMS

Lymph node (LN) stage is still the strongest prognostic marker in potentially curable gastric cancer. Accuracy of histopathological lymph node assessment depends on the number of investigated LNs and detection rate of metastases and micrometastases. The aim was to perform a feasibility study employing intra-arterial methylene blue injection - a novel method to improve LN harvest - and ex vivo sentinel LN mapping.

METHODS AND RESULTS

A total of 33 cases were enrolled, including 14 retrospective cases that served as a control group. The methylene group showed a highly significant improved mean LN harvest compared with unstained cases, with 38 +/- 14 versus 21 +/- 10 LNs (P < 0.001), respectively. The detection rate of ex vivo sentinel mapping was 88%. No skip metastases occurred.

CONCLUSION

Both techniques have the potential to improve the accuracy of histopathological LN staging and can be combined successfully.