AIM: To investigate the relationship between Helicobacter pylori(H. pylori) and mucin expression in gastric mucosa.METHODS: English Medical literature searches were conducted for gastric mucin expression in H. pylori ...AIM: To investigate the relationship between Helicobacter pylori(H. pylori) and mucin expression in gastric mucosa.METHODS: English Medical literature searches were conducted for gastric mucin expression in H. pylori infected people vs uninfected people. Searches wereperformed up to December 31 th 2014,using MEDLINE,Pub Med,EMBASE,Scopus,and CENTRAL. Studies comparing mucin expression in the gastric mucosa in patients positive and negative for H. pylori infection,were included. Meta-analysis was performed by using Comprehensive meta-analysis software(Version 3,Biostat Inc.,Englewood,NJ,United States). Pooled odds ratios(ORs) and 95% confidence intervals(CIs) were calculated compared mucin expression in individual studies by using the random effects model. Heterogeneity between studies was evaluated using the Cochran Q-test,and it was considered to be present if the Q-test P value was less than 0.10. I2 statistic was used to measure the proportion of inconsistency in individual studies,with I2 > 50% representing substantial heterogeneity. We also calculated a potential publication bias.RESULTS: Eleven studies,which represent 53 substudies of 15 different kinds of mucin expression,were selected according to the inclusion criteria. Every kind of mucin has been considered as one study. When a specific mucin has been studied in more than one paper,we combined the results in a nested metaanalysis of this particular mucin: MUC2,MUC6,STn,Paradoxical con A,Tn,T,Type 1 chain mucin,Le A,SLe A,Le B,AB-PAS,MUC1,and MUC5 AC. The odds ratio of mucin expression in random analysis was 2.33,95%CI: 1.230-4.411,P = 0.009,higher expression in H. pylori infected patients. Odds ratio for mucin expression in H. pylori positive patients was higher for MUC6(9.244,95%CI: 1.567-54.515,P = 0.014),and significantly lower for MUC5AC(0.447,95%CI: 0.211-0.949,P = 0.036). Thus,H. pylori infection may increase MUC6 expression and decrease MUC5 AC expression by 924% and 52%,respectively.CONCLUSION: H. pylori inhibits MUC5 AC expression in the gastric epithelium,and facilitates colonization. In contrast,increased MUC6 expression may help inhibiting colonization,using MUC6 antibiotics properties.展开更多
INTRODUCTIONHelicobacter pylori is recognized as a cause of chronicactive gastritis,gastric and duodenal ulcers,and gastriccancer,though the mechanisms of pathogenesis for H.pylori-associated diseases are not yet well...INTRODUCTIONHelicobacter pylori is recognized as a cause of chronicactive gastritis,gastric and duodenal ulcers,and gastriccancer,though the mechanisms of pathogenesis for H.pylori-associated diseases are not yet well understood.The ecological niche to which H.pylori is well-adapted展开更多
Ghrelin, a peptide hormone produced mainly in the stomach, has emerged recently as an important regulator of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzyme systems, the products of which play direct cytop...Ghrelin, a peptide hormone produced mainly in the stomach, has emerged recently as an important regulator of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzyme systems, the products of which play direct cytoprotective function in the maintenance of gastric mucosal integrity. In this study, using gastric mucosal cells, we report on the role of ghrelin in countering the cytotoxic effect of ethanol on mucin synthesis. We show that the countering effect of ghrelin on mucin synthesis was associated with the increase in NO and PGE2 production, and characterized by a marked up-regulation in cytosolic phospholipase A2 (cPLA2) activity. The ghrelin-induced up-regulation in mucin synthesis, like that of cPLA2 activity, was subject to suppression by Src inhibitor, PP2 and ERK inhibitor, PD98059, as well as ascorbate. Moreover, the loss in countering effect of ghrelin on the ethanol cytotoxicity and mucin synthesis was attained with cNOS inhibitor, L-NAME as well as COX-1 inhibitor SC-560. The effect of L-NAME was reflected in the inhibition of ghrelin-induced mucosal cell capacity for NO production, cPLA2 S-nitrosylation and PGE2 generation, whereas COX-1 inhibitor caused only the inhibition in PGE2 generation. Our findings suggest that the activation of gastric mucosal cPLA2 through cNOS-induced S-nitrosylation plays an essential role in the countering effect of ghrelin on the disturbances in gastric mucin synthesis caused by ethanol cytotoxicity.展开更多
Objective: To analyze the differences in clinicopathologic characteristics and prognosis between mucinous gastric carcinoma (MGC) and signet-ring cell carcinoma (SRCC). Methods: Clinicopathologic and prognostic ...Objective: To analyze the differences in clinicopathologic characteristics and prognosis between mucinous gastric carcinoma (MGC) and signet-ring cell carcinoma (SRCC). Methods: Clinicopathologic and prognostic data of 1,637 patients with histologically confirmed MGC or SRCC who received surgical operations in the Department of Gastroenterological Surgery, Beijing Cancer Hospital between December 2004 and December 2009 were retrospectively collected and analyzed. The clinicopathological features were analyzed statistically using Z2 test. Survival was analyzed using the Kaplan- Meier method and multivariate analysis of Cox proportional hazards regression model (backward, stepwise). Results: A total of 181 patients with gastric cancer (74 MGC, 107 SRCC) were included. MGC, when compared with SRCC, was featured by senile patients, stage III and I~, upper third stomach, large tumor size, positive lymph node metastasis, and positive lymphatic vascular invasion (P〈0.05). The overall 5-year survival rate showed no difference between the two groups (48.8% vs. 44.8%, P〉0.05). However, the survival rate for MGC patients was significant lower than that for SRCC patients when compared among the age 〈60 years, negative distant metastasis, and tumor localized at upper third stomach (P〈0.05). Multivariate Cox proportional hazards models revealed that distant metastasis was a significant independent prognostic indicator in MGC group, and lymph node metastasis and distant metastasis was significant independent prognostic indicators in SRCC group. Conclusions: While compared with SRCC, MGC is associated with a more aggressive tumor biologic behavior. There is no statistically significant difference in distant metastasis, an independent prognostic indicator for both MGC and SRCC, which might be the reason for no significant difference of the overall survival rate between the patients with MGC and SRCC.展开更多
BACKGROUND Recent evidence showed that combining endoscopic submucosal dissection(ESD)and laparoscopic sentinel lymph node dissection may avoid unnecessary gastrectomy in treating early mucinous gastric cancer(EMGC)pa...BACKGROUND Recent evidence showed that combining endoscopic submucosal dissection(ESD)and laparoscopic sentinel lymph node dissection may avoid unnecessary gastrectomy in treating early mucinous gastric cancer(EMGC)patients with risks of positive lymph node metastasis(pLNM).AIM To explore the predictive factors for pLNM in EMGC,and to optimize the clinical application of combing ESD and sentinel lymph node dissection in a proper subgroup of patients with EMGC.METHODS Thirty-one patients with EMGC who had undergone gastrectomy with lymph node dissection were consecutively enrolled from January 1988 to December 2016.Univariate and multivariate logistic regression analyses were used to estimate the association between the rates of pLNM and clinicopathological factors,providing odds ratio(OR)with 95%confidence interval.And the association between the number of predictors and the pLNM rate was also investigated.RESULTS Depth of invasion(OR=7.342,1.127-33.256,P=0.039),tumor diameter(OR=9.158,1.348-29.133,P=0.044),and lymphatic vessel involvement(OR=27.749,1.821-33.143,P=0.019)turned out to be significant and might be the independent risk factors for predicating pLNM in the multivariate analysis.For patients with 1,2,and 3 risk factors,the pLNM rates were 9.1%,33.3%,and 75.0%,respectively.pLNM was not detected in seven patients without any of these risk factors.CONCLUSION ESD might serve as a safe and sufficient treatment for intramucosal EMGC if tumor size≤2 cm,and when lymphatic vessel involvement is absent by postoperative histological examination.Combining ESD and sentinel lymph node dissection could be recommended as a safe and effective treatment for EMGC patients with a potential risk of pLNM.展开更多
Differentiated adenocarcinoma of the stomach is classified into gastric or intestinal phenotypes based on mucus expression. Recent advances in mucin histochemistry and immunohistochemistry have highlighted the importa...Differentiated adenocarcinoma of the stomach is classified into gastric or intestinal phenotypes based on mucus expression. Recent advances in mucin histochemistry and immunohistochemistry have highlighted the importance of such a distinction, and it is important clinically to distinguish between gastricand intestinal-type differentiated adenocarcinoma. However, a clinical and pathological diagnosis of this type is often difficult in early gastric cancer because of histological similarities between a hyperplastic epithelium and lowgrade atypia. Furthermore, determining tumor margins is often difficult, even with extensive preoperative examination. It is therefore critical to consider these diagnostic difficulties and different biological behaviors with high malignant potential when treating patients with gastric-type differentiated adenocarcinoma.展开更多
AIM: To investigate a relationship between the clinicopathological features and mucin phenotypes in advanced gastric adenocarcinoma (AGA). METHODS: Immunohistochemical staining was performed to determine the mucin phe...AIM: To investigate a relationship between the clinicopathological features and mucin phenotypes in advanced gastric adenocarcinoma (AGA). METHODS: Immunohistochemical staining was performed to determine the mucin phenotypes in 38 patients with differentiated adenocarcinomas (DACs), 9 with signet-ring cell carcinomas (SIGs), and 48 with other diffuse-type adenocarcinomas (non-SIGs) of AGA. The mucin phenotypes were classified into 4 types: gastric (G), gastrointestinal (GI), intestinal, and unclassified. RESULTS: The G-related mucin phenotypes were highly expressed in all the histological subtypes of AGA. The expression of the GI phenotype in SIG patients was lower than that in DAC patients (P = 0.02), and this phenotype was observed in 56% of the non-SIG patients in the intramucosal layer. Among non-SIG cases, the expression of the GI phenotype was significantly higherin patients with extended adenocarcinomas and those with positive rates of lymph node metastasis. There was no difference between the expressions of the G and other GI phenotypes factors. Among DAC and non-SIG patients, there were no differences between the survival rates of the corresponding patient groups. CONCLUSION: The GI phenotype might possess more invasive characteristics than the G phenotype in nonSIG. Neither of the phenotypes indicated a poor prognosis of DAC and non-SIG.展开更多
Gastric adenocarcinoma is one of the most common malignancies worldwide.Histochemical and immunohistologic analyses classify the phenotypes of gastric adenocarcinoma into several groups based on the variable clinical ...Gastric adenocarcinoma is one of the most common malignancies worldwide.Histochemical and immunohistologic analyses classify the phenotypes of gastric adenocarcinoma into several groups based on the variable clinical and pathologic features.A new and rare variant of gastric adenocarcinoma with chief cell differentiation(GA-CCD)has recently been recognized.Studies reporting the distinct clinicopathologic characteristics proposed the term oxyntic gland polyp/adenoma because of the benign nature of the GACCD.Typically,GA-CCD is a solitary mucosal lesion that develops either in the gastric cardia or fundus.Histologically,this lesion is characterized by tightly clustered glands and anastomosing cords of chief cells.Immunohistochemically,GA-CCD is diffusely positive for mucin(MUC)6 and negative for MUC2and MUC5AC.However,other gastric tumors such as a gastric neuroendocrine tumor or fundic gland polyp have been difficult to exclude.Because GA-CCD tends to be endoscopically misdiagnosed as a neuroendocrine tumor or fundic gland polyp,comprehensive assessment and observation by an endoscopist are strongly recommended.Herein,we report a rare case of oxyntic gland adenoma endoscopically mimicking a gastric neuroendocrine tumor that was successfully removed by endoscopic mucosal resection.展开更多
AIM:To identify those with a micropapillary pattern,ascertain relative frequency and document clinicopathological characteristics by reviewing gastric carcinomas.METHODS:One hundred and fifty-one patients diagnosed wi...AIM:To identify those with a micropapillary pattern,ascertain relative frequency and document clinicopathological characteristics by reviewing gastric carcinomas.METHODS:One hundred and fifty-one patients diagnosed with gastric cancer who underwent gastrectomy were retrospectively studied and the presence of a regional invasive micropapillary component was evaluated by light microscopy.All available hematoxylin-eosin(HE)-stained slides were histologically reviewed and 5 tumors were selected as putative micropapillary carcinoma when cancer cell clusters without a vascular core within empty lymphatic-like space comprised at least5%of the tumor.Tumor tissues from these 5 invasive gastric carcinomas were immunostained using an antimucin 1(MUC1)antibody(clone MA695)to detect the characteristic inside-out pattern and with D2-40antibody to determine the presence of intratumoral lymph vessels.Detection of intraepithelial neutrophil apoptosis was evaluated in consecutive histological tissue sections by three independent methods,namely light microscopy with HE staining,the conventional terminal deoxynucleotidyl transferase-mediated d UTP-biotin nick end-labeling(TUNEL)method and immunohistochemistry for activated caspase-3(clone C92-605).RESULTS:Among 151 gastric cancers resected for cure,5(3.3%)were adenocarcinomas with a micropapillary component.Four of the patients died of disease from 6 to 23 mo and one patient was alive with metastases at 9 mo.All patients had advanced-stage cancer(≥p T2)and lymph node metastasis.Positive MUC1 immunostaining on the stroma-facing surface(inside-out pattern)of the carcinomatous cluster cells,together with negative immunostaining for D2-40 in the cells limiting lymphatic-like spaces,confirmed the true micropapillary pattern in these gastric neoplasms.In all five cases,several micropapillae were infiltrated by neutrophils.HE staining,TUNEL assay and immunostaining for caspase-3 demonstrated apoptoticneutrophils within cytoplasmic vacuoles of tumor cells.These data suggest phagocytosis(cannibalism)of apoptotic neutrophils by micropapillary tumor cells.Tumor cell cannibalism is usually found in aggressive tumors with anaplastic morphology.Our data extend these observations to gastric micropapillary carcinoma:a tumor histotype analogously characterized by aggressive behavior and poor prognosis.The results are of interest because they raise the intriguing possibility that neutrophil cannibalism by tumor cells may be one of the mechanisms favoring tumor growth in gastric micropapillary carcinomas.CONCLUSION:This is the first study showing phagocytosis(cannibalism)of apoptotic neutrophils by tumor cells in gastric micropapillary carcinomas.展开更多
文摘AIM: To investigate the relationship between Helicobacter pylori(H. pylori) and mucin expression in gastric mucosa.METHODS: English Medical literature searches were conducted for gastric mucin expression in H. pylori infected people vs uninfected people. Searches wereperformed up to December 31 th 2014,using MEDLINE,Pub Med,EMBASE,Scopus,and CENTRAL. Studies comparing mucin expression in the gastric mucosa in patients positive and negative for H. pylori infection,were included. Meta-analysis was performed by using Comprehensive meta-analysis software(Version 3,Biostat Inc.,Englewood,NJ,United States). Pooled odds ratios(ORs) and 95% confidence intervals(CIs) were calculated compared mucin expression in individual studies by using the random effects model. Heterogeneity between studies was evaluated using the Cochran Q-test,and it was considered to be present if the Q-test P value was less than 0.10. I2 statistic was used to measure the proportion of inconsistency in individual studies,with I2 > 50% representing substantial heterogeneity. We also calculated a potential publication bias.RESULTS: Eleven studies,which represent 53 substudies of 15 different kinds of mucin expression,were selected according to the inclusion criteria. Every kind of mucin has been considered as one study. When a specific mucin has been studied in more than one paper,we combined the results in a nested metaanalysis of this particular mucin: MUC2,MUC6,STn,Paradoxical con A,Tn,T,Type 1 chain mucin,Le A,SLe A,Le B,AB-PAS,MUC1,and MUC5 AC. The odds ratio of mucin expression in random analysis was 2.33,95%CI: 1.230-4.411,P = 0.009,higher expression in H. pylori infected patients. Odds ratio for mucin expression in H. pylori positive patients was higher for MUC6(9.244,95%CI: 1.567-54.515,P = 0.014),and significantly lower for MUC5AC(0.447,95%CI: 0.211-0.949,P = 0.036). Thus,H. pylori infection may increase MUC6 expression and decrease MUC5 AC expression by 924% and 52%,respectively.CONCLUSION: H. pylori inhibits MUC5 AC expression in the gastric epithelium,and facilitates colonization. In contrast,increased MUC6 expression may help inhibiting colonization,using MUC6 antibiotics properties.
基金the Research Service of the Henry Ford Health Sciences Center and Research Foundation(JCB,RSB)National Cancer Institute Grant R01 CA69480(RSB)
文摘INTRODUCTIONHelicobacter pylori is recognized as a cause of chronicactive gastritis,gastric and duodenal ulcers,and gastriccancer,though the mechanisms of pathogenesis for H.pylori-associated diseases are not yet well understood.The ecological niche to which H.pylori is well-adapted
文摘Ghrelin, a peptide hormone produced mainly in the stomach, has emerged recently as an important regulator of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzyme systems, the products of which play direct cytoprotective function in the maintenance of gastric mucosal integrity. In this study, using gastric mucosal cells, we report on the role of ghrelin in countering the cytotoxic effect of ethanol on mucin synthesis. We show that the countering effect of ghrelin on mucin synthesis was associated with the increase in NO and PGE2 production, and characterized by a marked up-regulation in cytosolic phospholipase A2 (cPLA2) activity. The ghrelin-induced up-regulation in mucin synthesis, like that of cPLA2 activity, was subject to suppression by Src inhibitor, PP2 and ERK inhibitor, PD98059, as well as ascorbate. Moreover, the loss in countering effect of ghrelin on the ethanol cytotoxicity and mucin synthesis was attained with cNOS inhibitor, L-NAME as well as COX-1 inhibitor SC-560. The effect of L-NAME was reflected in the inhibition of ghrelin-induced mucosal cell capacity for NO production, cPLA2 S-nitrosylation and PGE2 generation, whereas COX-1 inhibitor caused only the inhibition in PGE2 generation. Our findings suggest that the activation of gastric mucosal cPLA2 through cNOS-induced S-nitrosylation plays an essential role in the countering effect of ghrelin on the disturbances in gastric mucin synthesis caused by ethanol cytotoxicity.
文摘Objective: To analyze the differences in clinicopathologic characteristics and prognosis between mucinous gastric carcinoma (MGC) and signet-ring cell carcinoma (SRCC). Methods: Clinicopathologic and prognostic data of 1,637 patients with histologically confirmed MGC or SRCC who received surgical operations in the Department of Gastroenterological Surgery, Beijing Cancer Hospital between December 2004 and December 2009 were retrospectively collected and analyzed. The clinicopathological features were analyzed statistically using Z2 test. Survival was analyzed using the Kaplan- Meier method and multivariate analysis of Cox proportional hazards regression model (backward, stepwise). Results: A total of 181 patients with gastric cancer (74 MGC, 107 SRCC) were included. MGC, when compared with SRCC, was featured by senile patients, stage III and I~, upper third stomach, large tumor size, positive lymph node metastasis, and positive lymphatic vascular invasion (P〈0.05). The overall 5-year survival rate showed no difference between the two groups (48.8% vs. 44.8%, P〉0.05). However, the survival rate for MGC patients was significant lower than that for SRCC patients when compared among the age 〈60 years, negative distant metastasis, and tumor localized at upper third stomach (P〈0.05). Multivariate Cox proportional hazards models revealed that distant metastasis was a significant independent prognostic indicator in MGC group, and lymph node metastasis and distant metastasis was significant independent prognostic indicators in SRCC group. Conclusions: While compared with SRCC, MGC is associated with a more aggressive tumor biologic behavior. There is no statistically significant difference in distant metastasis, an independent prognostic indicator for both MGC and SRCC, which might be the reason for no significant difference of the overall survival rate between the patients with MGC and SRCC.
文摘BACKGROUND Recent evidence showed that combining endoscopic submucosal dissection(ESD)and laparoscopic sentinel lymph node dissection may avoid unnecessary gastrectomy in treating early mucinous gastric cancer(EMGC)patients with risks of positive lymph node metastasis(pLNM).AIM To explore the predictive factors for pLNM in EMGC,and to optimize the clinical application of combing ESD and sentinel lymph node dissection in a proper subgroup of patients with EMGC.METHODS Thirty-one patients with EMGC who had undergone gastrectomy with lymph node dissection were consecutively enrolled from January 1988 to December 2016.Univariate and multivariate logistic regression analyses were used to estimate the association between the rates of pLNM and clinicopathological factors,providing odds ratio(OR)with 95%confidence interval.And the association between the number of predictors and the pLNM rate was also investigated.RESULTS Depth of invasion(OR=7.342,1.127-33.256,P=0.039),tumor diameter(OR=9.158,1.348-29.133,P=0.044),and lymphatic vessel involvement(OR=27.749,1.821-33.143,P=0.019)turned out to be significant and might be the independent risk factors for predicating pLNM in the multivariate analysis.For patients with 1,2,and 3 risk factors,the pLNM rates were 9.1%,33.3%,and 75.0%,respectively.pLNM was not detected in seven patients without any of these risk factors.CONCLUSION ESD might serve as a safe and sufficient treatment for intramucosal EMGC if tumor size≤2 cm,and when lymphatic vessel involvement is absent by postoperative histological examination.Combining ESD and sentinel lymph node dissection could be recommended as a safe and effective treatment for EMGC patients with a potential risk of pLNM.
文摘Differentiated adenocarcinoma of the stomach is classified into gastric or intestinal phenotypes based on mucus expression. Recent advances in mucin histochemistry and immunohistochemistry have highlighted the importance of such a distinction, and it is important clinically to distinguish between gastricand intestinal-type differentiated adenocarcinoma. However, a clinical and pathological diagnosis of this type is often difficult in early gastric cancer because of histological similarities between a hyperplastic epithelium and lowgrade atypia. Furthermore, determining tumor margins is often difficult, even with extensive preoperative examination. It is therefore critical to consider these diagnostic difficulties and different biological behaviors with high malignant potential when treating patients with gastric-type differentiated adenocarcinoma.
文摘AIM: To investigate a relationship between the clinicopathological features and mucin phenotypes in advanced gastric adenocarcinoma (AGA). METHODS: Immunohistochemical staining was performed to determine the mucin phenotypes in 38 patients with differentiated adenocarcinomas (DACs), 9 with signet-ring cell carcinomas (SIGs), and 48 with other diffuse-type adenocarcinomas (non-SIGs) of AGA. The mucin phenotypes were classified into 4 types: gastric (G), gastrointestinal (GI), intestinal, and unclassified. RESULTS: The G-related mucin phenotypes were highly expressed in all the histological subtypes of AGA. The expression of the GI phenotype in SIG patients was lower than that in DAC patients (P = 0.02), and this phenotype was observed in 56% of the non-SIG patients in the intramucosal layer. Among non-SIG cases, the expression of the GI phenotype was significantly higherin patients with extended adenocarcinomas and those with positive rates of lymph node metastasis. There was no difference between the expressions of the G and other GI phenotypes factors. Among DAC and non-SIG patients, there were no differences between the survival rates of the corresponding patient groups. CONCLUSION: The GI phenotype might possess more invasive characteristics than the G phenotype in nonSIG. Neither of the phenotypes indicated a poor prognosis of DAC and non-SIG.
文摘Gastric adenocarcinoma is one of the most common malignancies worldwide.Histochemical and immunohistologic analyses classify the phenotypes of gastric adenocarcinoma into several groups based on the variable clinical and pathologic features.A new and rare variant of gastric adenocarcinoma with chief cell differentiation(GA-CCD)has recently been recognized.Studies reporting the distinct clinicopathologic characteristics proposed the term oxyntic gland polyp/adenoma because of the benign nature of the GACCD.Typically,GA-CCD is a solitary mucosal lesion that develops either in the gastric cardia or fundus.Histologically,this lesion is characterized by tightly clustered glands and anastomosing cords of chief cells.Immunohistochemically,GA-CCD is diffusely positive for mucin(MUC)6 and negative for MUC2and MUC5AC.However,other gastric tumors such as a gastric neuroendocrine tumor or fundic gland polyp have been difficult to exclude.Because GA-CCD tends to be endoscopically misdiagnosed as a neuroendocrine tumor or fundic gland polyp,comprehensive assessment and observation by an endoscopist are strongly recommended.Herein,we report a rare case of oxyntic gland adenoma endoscopically mimicking a gastric neuroendocrine tumor that was successfully removed by endoscopic mucosal resection.
文摘AIM:To identify those with a micropapillary pattern,ascertain relative frequency and document clinicopathological characteristics by reviewing gastric carcinomas.METHODS:One hundred and fifty-one patients diagnosed with gastric cancer who underwent gastrectomy were retrospectively studied and the presence of a regional invasive micropapillary component was evaluated by light microscopy.All available hematoxylin-eosin(HE)-stained slides were histologically reviewed and 5 tumors were selected as putative micropapillary carcinoma when cancer cell clusters without a vascular core within empty lymphatic-like space comprised at least5%of the tumor.Tumor tissues from these 5 invasive gastric carcinomas were immunostained using an antimucin 1(MUC1)antibody(clone MA695)to detect the characteristic inside-out pattern and with D2-40antibody to determine the presence of intratumoral lymph vessels.Detection of intraepithelial neutrophil apoptosis was evaluated in consecutive histological tissue sections by three independent methods,namely light microscopy with HE staining,the conventional terminal deoxynucleotidyl transferase-mediated d UTP-biotin nick end-labeling(TUNEL)method and immunohistochemistry for activated caspase-3(clone C92-605).RESULTS:Among 151 gastric cancers resected for cure,5(3.3%)were adenocarcinomas with a micropapillary component.Four of the patients died of disease from 6 to 23 mo and one patient was alive with metastases at 9 mo.All patients had advanced-stage cancer(≥p T2)and lymph node metastasis.Positive MUC1 immunostaining on the stroma-facing surface(inside-out pattern)of the carcinomatous cluster cells,together with negative immunostaining for D2-40 in the cells limiting lymphatic-like spaces,confirmed the true micropapillary pattern in these gastric neoplasms.In all five cases,several micropapillae were infiltrated by neutrophils.HE staining,TUNEL assay and immunostaining for caspase-3 demonstrated apoptoticneutrophils within cytoplasmic vacuoles of tumor cells.These data suggest phagocytosis(cannibalism)of apoptotic neutrophils by micropapillary tumor cells.Tumor cell cannibalism is usually found in aggressive tumors with anaplastic morphology.Our data extend these observations to gastric micropapillary carcinoma:a tumor histotype analogously characterized by aggressive behavior and poor prognosis.The results are of interest because they raise the intriguing possibility that neutrophil cannibalism by tumor cells may be one of the mechanisms favoring tumor growth in gastric micropapillary carcinomas.CONCLUSION:This is the first study showing phagocytosis(cannibalism)of apoptotic neutrophils by tumor cells in gastric micropapillary carcinomas.