Signet ring cell type and other histologic types: differing clinical course and prognosis in T1 gastric cancer

Impact of Alcian blue and periodic acid Schiff expression on the prognosis of gastric signet ring cell carcinoma

BACKGROUND

The Alcian blue (AB) and periodic acid Schiff (PAS) stains are representative mucus markers in gastric signet ring cell carcinoma (SRCC). They are low-cost special staining methods used to detect acidic mucus and neutral mucus, respectively. However, the clinical importance of the special combined AB and PAS stain is unclear.

AIM

To investigate AB expression, PAS expression and the AB-to-PAS (A/P) ratio in gastric SRCC patients and to assess patient prognosis.

METHODS

Paraffin-embedded sections from 83 patients with gastric SRCC were stained with AB and PAS, and signet ring cell positivity was assessed quantitatively. Immunohistochemical staining for Ki67, protein 53 (P53) and human epidermal growth factor receptor 2 (HER2) was performed simultaneously. The cancer-specific survival (CSS) rate was estimated via Kaplan-Meier analysis. Cox proportional hazards models were used for univariate and multivariate survival analyses.

RESULTS

Kaplan-Meier survival analysis revealed that the 3-year CSS rate was significantly greater in the high-PAS-expression subgroup than in the low-PAS-expression subgroup (P < 0.001). The 3-year CSS rate in the A/P ≤ 0.5 group was significantly greater than that in the A/P > 0.5 group (P = 0.042). Univariate Cox regression analysis revealed that the factors affecting prognosis included tumor diameter, lymph node metastasis, vessel carcinoma embolus, tumor stage, the A/P ratio and the expression of Ki67, P53 and the PAS. Cox multivariate regression analysis confirmed that low PAS expression [hazard ratio (HR) = 3.809, 95% confidence interval (CI): 1.563-9.283, P = 0.003] and large tumor diameter (HR = 2.761, 95%CI: 1.086-7.020, P = 0.033) were independent risk factors for poor prognosis.

CONCLUSION

A/P > 0.5 is potentially a risk factor for prognosis, and low PAS expression is an independent risk factor in the prognosis of gastric SRCC. PAS expression and the A/P ratio could help in predicting the clinical prognosis of patients with SRCC.

Clinical Features of Gastric Signet Ring Cell Cancer: Results from a Systematic Review and Meta-Analysis

BACKGROUND

Conflicting results about the prognostic relevance of signet ring cell histology in gastric cancer have been reported. We aimed to perform a meta-analysis focusing on the clinicopathological features and prognosis of this subgroup of cancer compared with other histologies.

METHODS

A systematic literature search in the PubMed database was conducted, including all publications up to 1 October 2021. A meta-analysis comparing the results of the studies was performed.

RESULTS

A total of 2062 studies referring to gastric cancer with signet ring cell histology were identified, of which 262 studies reported on its relationship with clinical information. Of these, 74 were suitable to be included in the meta-analysis. A slightly lower risk of developing nodal metastases in signet ring cell tumours compared to other histotypes was found (especially to undifferentiated/poorly differentiated/mucinous and mixed histotypes); the lower risk was more evident in early and slightly increased in advanced gastric cancer. Survival tended to be better in early stage signet ring cell cancer compared to other histotypes; no differences were shown in advanced stages, and survival was poorer in metastatic patients. In the subgroup analysis, survival in signet ring cell cancer was slightly worse compared to non-signet ring cell cancer and differentiated/well-to-moderately differentiated adenocarcinoma.

CONCLUSIONS

Most of the conflicting results in signet ring cell gastric cancer literature could be derived from the lack of standardisation in their classification and the comparison with the different subtypes of gastric cancer. There is a critical need to strive for a standardised classification system for gastric cancer, fostering clarity and coherence in the forthcoming research and clinical applications.

SAMD4A serves as a negative prognostic marker for gastric cancer patients

INTRODUCTION

The incidence and mortality of gastric cancer remain high in the world. We aim to explore the role of SAMD4A in gastric cancer.

METHODS

The expression of SAMD4A was up-regulated in gastric adenocarcinoma and the expression level of SAMD4A in gastric adenocarcinoma and adjacent normal tissues was verified by RT-qPCR. Immunohistochemical showed that SAMD4A was mainly located in the cytoplasm.

RESULT

The result showed that the expression of SAMD4A was positively correlated with the depth of invasion, the number of lymph node metastasis, and the clinical stage in patients with gastric adenocarcinoma. Survival analysis of GEPIA database showed that the overall survival of gastric adenocarcinoma patients with positive SAMD4A expression was lower than that of the negative group. Gastric cancer cell lines with knockdown of the SAMD4A gene were used to observe the differences in cell proliferation, invasion, and migration abilities between the knockdown group and the control group. The results showed that the proliferation, invasion, and migration abilities of the SAMD4A knockdown group were both weakened compared with the control group. This study is the first to find that the expression level of SAMD4A in gastric cancer is higher than that in the adjacent group and is associated with poor prognosis of patients. SAMD4A promotes the proliferation, invasion, and migration of gastric adenocarcinoma cells.

CONCLUSION

This indicates that SAMD4A plays an important role in the occurrence and development of gastric cancer, and is expected to be an effective indicator for the diagnosis and evaluation of the prognosis of gastric cancer.

Feasibility for the application of expanded endoscopic resection criteria in mucosal undifferentiated gastric cancer

BACKGROUND & AIM

The indication of endoscopic submucosal dissection (ESD) for mucosal undifferentiated early gastric cancer (EGC) remains controversial because of risk of lymph node metastasis (LNM). The aim of this study was to identify risk factors for lymph node metastasis (LNM) in mucosal undifferentiated EGC, and further to confirm feasibility of the ESD for the treatment of mucosal undifferentiated EGC.

METHODS

We retrospectively reviewed data of patients who underwent surgical resection with lymph node dissection of T1a stage primary gastric adenocarcinoma at three medical centers between 2012 and 2022. We evaluated the frequency of lymph node metastasis and the associated risk factors, as well as the lymph node metastasis rate in the expanded indication of mucosal undifferentiated EGC.

RESULTS

A total of 100 surgically treated patients with mucosal undifferentiated EGC were enrolled. LNM was irrelevant to the age, tumor size, location, and macroscopic type (all P > 0.05), while it was significantly associated with lymphovascular invasion (LVI, P ＜0.001). And logistic regression analysis showed that the LVI was the only significant risk factors for LNM (OR: 0.34, 95%CI: 0.06-0.204; P ＜0.001). Of 44 mucosal undifferentiated EGC patients satisfying the expanded indication of ESD, 3 patients (6.8%) showed LN metastasis, all of them with undifferentiated cancer without ulceration, less than 2.0 cm in size.

CONCLUSIONS

Because LNM is present in mucosal undifferentiated EGC patients who satisfied the expanded indication of ESD, ESD cannot be considered a better choice than surgery for all undifferentiated EGC patients. LVI was significant risk factors for LNM in patients with mucosal undifferentiated EGC.

The differences in biological behavior and gene expression characteristics between pure and mixed early gastric signet ring cell carcinomas

BACKGROUND

The biological behavior of signet ring cell carcinoma (SRCC) in early gastric cancer (EGC) is not well understood.

AIMS

We aimed to investigate the clinicopathologic and prognostic differences, and explore differences in the gene expression characteristics between pure early SRCC and mixed early SRCC.

METHODS

We retrospectively analyzed 1707 EGC patients. We also conducted a meta-analysis to compare biological behavior in pure SRCC and mixed SRCC. We explored gene expression levels of N6-methyadenosine (m6A) regulators in pure SRCC and mixed SRCC.

RESULTS

Compared with pure SRCC, mixed SRCC was associated with an increased risk of submucosal invasion, perineural invasion, LVI and LNM. LNM was more common in mixed SRCC than with pure SRCC who met the indications for endoscopic submucosal dissection (ESD) (16.67% vs 2.78%). There was no difference in the overall survival between pure SRCC and mixed SRCC in EGCs (P=0.10). Expression of m6A regulators WTAP, FTO and VIRMA was significantly higher in mixed SRCC than that in pure SRCC (P<0.05).

CONCLUSION

Mixed SRCC displayed more aggressive biological behavior than pure SRCC in EGC. WTAP, FTO and VIRMA were expressed at significantly different levels in the two types of EGC, and may have important roles in the observed differences in biological behavior.

A Standardized Pathology Report for Gastric Cancer: 2nd Edition

The first edition of 'A Standardized Pathology Report for Gastric Cancer' was initiated by the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists and published 17 years ago. Since then, significant advances have been made in the pathologic diagnosis, molecular genetics, and management of gastric cancer (GC). To reflect those changes, a committee for publishing a second edition of the report was formed within the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. This second edition consists of two parts: standard data elements and conditional data elements. The standard data elements contain the basic pathologic findings and items necessary to predict the prognosis of GC patients, and they are adequate for routine surgical pathology service. Other diagnostic and prognostic factors relevant to adjuvant therapy, including molecular biomarkers, are classified as conditional data elements to allow each pathologist to selectively choose items appropriate to the environment in their institution. We trust that the standardized pathology report will be helpful for GC diagnosis and facilitate large-scale multidisciplinary collaborative studies.

A standardized pathology report for gastric cancer: 2nd edition

The first edition of 'A Standardized Pathology Report for Gastric Cancer' was initiated by the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists and published 17 years ago. Since then, significant advances have been made in the pathologic diagnosis, molecular genetics, and management of gastric cancer (GC). To reflect those changes, a committee for publishing a second edition of the report was formed within the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. This second edition consists of two parts: standard data elements and conditional data elements. The standard data elements contain the basic pathologic findings and items necessary to predict the prognosis of GC patients, and they are adequate for routine surgical pathology service. Other diagnostic and prognostic factors relevant to adjuvant therapy, including molecular biomarkers, are classified as conditional data elements to allow each pathologist to selectively choose items appropriate to the environment in their institution. We trust that the standardized pathology report will be helpful for GC diagnosis and facilitate large-scale multidisciplinary collaborative studies.

Poorly cohesive cells gastric carcinoma including signet-ring cell cancer: Updated review of definition, classification and therapeutic management

While the incidence of gastric cancer (GC) in general has decreased worldwide in recent decades, the incidence of diffuse cancer historically comprising poorly cohesive cells-GC (PCC-GC) and including signet ring cell cancer is rising. Literature concerning PCC-GC is scarce and unclear, mostly due to a large variety of historically used definitions and classifications. Compared to other histological subtypes of GC, PCC-GC is nevertheless characterized by a distinct set of epidemiological, histological and clinical features which require a specific diagnostic and therapeutic approach. The aim of this review was to provide an update on the definition, classification and therapeutic strategies of PCC-GC. We focus on the updated histological definition of PCC-GC, along with its implications on future treatment strategies and study design. Also, specific considerations in the diagnostic management are discussed. Finally, the impact of some recent developments in the therapeutic management of GC in general such as the recently validated taxane-based regimens (5-Fluorouracil, leucovorin, oxaliplatin and docetaxel), the use of hyperthermic intraperitoneal chemotherapy as well as pressurized intraperitoneal aerosol chemotherapy and targeted therapy have been reviewed in depth for their relative importance for PCC-GC in particular.

Adenocarcinoma with Mixed Subtypes in the Early and Advanced Gastric Cancer

Objective

Adenocarcinoma with mixed subtypes (AM) is a histological classification based on the WHO classification. We aimed to compare the prognosis among AM, classic adenocarcinoma (CA), mucinous adenocarcinoma (MAC), and signet-ring cell carcinoma (SRCC) in early and advanced gastric cancer (EGC and AGC), respectively.

Methods

The Surveillance, Epidemiology, and End Results (SEER) database was queried from 2001 to 2016. Univariate and multivariate Cox analyses were performed to compare prognosis between AM and histologic subtypes of CA, SRCC, and MAC in ECG and ACG. A nomogram was established to predict the cancer-specific survival (CSS) of gastric cancer (GC) patients with AM. C-index, calibration curves, and receiver operating characteristic (ROC) and decision curve analysis (DCA) curves were applied to examine the accuracy and clinical benefits.

Results

In the prognosis among these four histological subtypes in EGC patients, there are no differences. For AGC patients, AM had a significantly poorer prognosis compared with CA and MAC (P=0.003, 0.029) but similar prognosis to SRCC. A nomogram based on race, T stage, N stage, M stage, and surgical modalities was proposed to predict 1- and 3-year CSS for GC patients with AM (C-index: training cohort: 0.804, validation cohort: 0.748. 1- and 3-year CSS AUC: training cohort: 0.871 and 0.914, validation cohort: 0.810 and 0.798). 1- and 3-year CSS DCA curves showed good net benefits.

Conclusions

EGC patients with AM had similar survival to those with CA, MAC, and SRCC. AM was an independent predictor of poor prognosis in AGC. A nomogram for predicting the prognosis of GC patients with AM was proposed to quantitatively assess the long-term survival.

Signet ring cell percentage in poorly cohesive gastric cancer patients: A potential novel predictor of survival

BACKGROUND AND OBJECTIVES

Signet ring cells (SRC) are widely acknowledged as a prognostically unfavorable histotype amongst poorly cohesive gastric cancer. In this study we evaluated the impact of SRC percentage on the clinical, pathological and prognostic features of these tumors according to the classification by the European Chapter of the IGCA.

METHODS

We retrospectively reviewed records of patients with poorly cohesive gastric cancer that underwent surgery between 1995 and 2016, whose tissue specimens were available in a biological bank. All slides were put under revision, patients were reclassified into three groups according to the proportion of signet ring cells: "pure" SRC (containing ≥90% of SRCs), Poorly Cohesive-Not Otherwise Specified (PC-NOS) (containing ≤10% of SRCs), and PC-NOS/SRC (containing <90% but >10% of SRCs). The clinicopathological factors between different types were analyzed and prognostic differences were compared.

RESULTS

Among 143 enrolled patients, 51% were male and 49% were female. The mean (±SD) age at diagnosis was 61 ± 13.9 years. Eighty-seven patients (60.8%) were reclassified as PC-NOS, 56 (39.2%) as PC-NOS/SRC and none as "pure" SRC. Five-years overall survival was significantly higher in PC-NOS/SRC group (63.3%) compared with PC-NOS group (12.7%). The increase in mortality risk was more than four-fold in patients with PC-NOS pattern compared to those with PC-NOS/SRC (HR 4.32 [95% CI 2.5-7.4]. After adjustment for potential confounding factors, SRC pattern was still an independent predictor of survival.

CONCLUSIONS

The percentage of SRCs is inversely related to tumor aggressiveness, confirming the role of SRC pattern as an independent predictor of survival.

Prognostic Significance of Signet-Ring Cell Components in Patients With Gastric Carcinoma of Different Stages

Background: Gastric carcinoma (GC), which contains signet ring cell (SRC) components are frequently observed in postoperative pathological assessment. This study aims to study the prognostic significance of SRC components in GC patients.

Methods: From 2003 to 2017, surgically resected primary GC patients were retrospectively reviewed. All enrolled patients were divided into three groups according to the proportion of SRC. The overall survival (OS) and disease-free survival (DFS) of GC patients with different tumor stages were analyzed.

Results: Patients with SRC or mixed-SRC were more associated with female, younger age, middle or lower third of the stomach, larger tumor, higher pN stage, and more lymphovascular invasion. For GC patients in stage I, multivariate survival analysis showed that age >60, SRC components >50%, and pT stage were independent prognostic factors for OS (all p < 0.05). The 5-year OS of patients with SRC were higher than that of patients with pure adenocarcinoma (p = 0.021). For GC patients in stage II/III, multivariate survival analysis showed that age >60, SRC proportion, surgical types, Borrmann's type, pT stage, pN stage, and lymphovascular invasion were independent prognostic factors for OS (all p < 0.05). The 5-year OS/DFS of patients with SRC were lower than that of patients with pure adenocarcinoma (p < 0.001).

Conclusions: SRC seemed to be a favorable prognostic factor in GC patients in stage I. However, for GC patients in stage II/III, the SRC components were associated with poor prognosis, independent of other clinicopathological factors.

Prognosis and Biological Behavior of Gastric Signet-Ring Cell Carcinoma Better or Worse: A Meta-Analysis

BACKGROUND

The clinical pathology of gastric signet-ring cell carcinoma (SRC) is still unclear. This meta-analysis was performed to evaluate the difference in biological behavior and prognosis between SRC and non-signet ring cell carcinoma (NSRC).

METHODS

A total of 58 eligible studies were analyzed using RevMan and other auxiliary software. Biological behaviors were compared based on odds ratio (OR) and mean difference (MD). Hazards ratio (HR) was calculated for prognosis based on Kaplan-Meier curves.

RESULTS

Totally, 28,946 SRC patients were compared with 81,917 NSRC patients. Compared with NSRC patients, lower male: female ratio (OR = 0.53, P < 0.01), younger age (MD = -4.89, P < 0.01), more middle location (OR = 1.64, P < 0.01), more depressed type at early stage (OR = 1.31, P < 0.05), higher incidence of Borrmann type IV (OR = 1.96, P < 0.01), less lymph node metastasis at early stage (OR = 0.78, P < 0.05), better prognosis at early stage (HR = 0.59, P < 0.01), and worse prognosis at advanced stage (HR = 1.19, P < 0.01) were associated with SRC patients.

CONCLUSION

The prognosis of SRC at early stage is better than other types of gastric cancer, while that of SRC at advanced stage is relatively poorer.

Difference Between Signet Ring Cell Gastric Cancers and Non-Signet Ring Cell Gastric Cancers: A Systematic Review and Meta-Analysis

Background: There is controversy about the characteristics and prognostic implications of signet ring cell gastric cancers and non-signet ring cell gastric cancers.

Objective: This study aims to evaluate clinicopathological characteristics and prognoses of signet ring cell carcinoma (SRCC) and non-signet ring cell carcinoma (NSRCC) of stomach.

Methods: Studies compared between SRCC and NSRCC of the stomach after gastrectomy and published before September 1st, 2020, in the PubMed, Cochrane, and Embase databases, were identified systematically.

Results: A total of 2,865 studies were screened, and 36 studies were included, with 19,174 patients in the SRCC group and 55,942 patients in the NSRCC group. SRCC patients were younger in age (P < 0.001), less likely to be male patients (P < 0.001), more afflicted with upper third lesions (P < 0.001), and presenting with more Borrmann type IV tumors (P = 0.005) than NSRCC patients. Lymph nodes metastasis was similar between SRCC and NSRCC patients with advanced tumor stage (OR: 0.86, 95% CI: 0.671.10, P = 0.23), but lower in the SRCC than NSRCC patients with early tumor stage (OR: 0.73; 95% CI: 0.560.98, P = 0.02). SRCC patients had comparable survival outcomes with NSRCC patients for early gastric cancers (HR: 1.05, 95% CI: 0.651.68, P < 0.001) but had significantly poor prognosis for patients with advanced tumor stage (HR: 1.50, 95% CI: 1.281.76, P < 0.001).

Conclusions: Signet ring cell carcinomas of the stomach are an increasingly common histopathological subtype of gastric cancers. These kinds of patients tend to be younger in age and more often female. Although, signet ring cell gastric cancer is a negative prognostic factor for patients with advanced stage. The difference is that for early stage of signet ring cell gastric cancers, it has low lymph nodes metastasis rate and comparable prognosis with non-signet ring cell cancers.

Prognostic analysis of gastric signet ring cell carcinoma and mucinous carcinoma: a propensity score-matched study and competing risk analysis

Background: Limited evidence and contradictory results have been reported regarding the impact of signet ring cell carcinoma (SRC) and mucinous gastric cancer (MGC) classifications on the prognosis of gastric cancer (GC).

Results: Information on 6017 patients and 266 patients was extracted from the SEER database and our hospital records, respectively. We found that patients with MGC had a better survival rate than those with SRC (P=0.012), but in the early stage, MGC was a risk factor for a poor prognosis. After PSM, for both patients from the SEER database and our hospital, the prognosis of patients with SRC was poorer than that of patients with MGC (P<0.05), but patients with MGC in early-stage GC showed poorer survival. Additionally, SRC was demonstrated to be a risk factor in the multivariate competing risk regression model for cancer-specific survival.

Conclusion: Patients with SRC may have a worse prognosis than those with MGC, but for early-stage GC, patients with SRC have a better prognosis than those with MGC.

Method: Patients from the SEER database and from our hospital diagnosed with SRC or MGC were included in a Cox regression analysis, multivariate competing risk model and propensity score matching (PSM) analysis.

Predictors of Lymph Node Metastasis and Differences Between Pure and Mixed Histologic Types of Early Gastric Signet-ring Cell Carcinomas

The aim of this study was to investigate predictors of lymph node metastasis (LNM) in early gastric signet-ring cell carcinoma (SRCC) and determine clinicopathologic and prognostic differences of different histologic subtypes. We retrospectively analyzed 13,661 gastric cancer patients; 231 were eligible for inclusion. Data for clinical, endoscopic, and histopathologic characteristics and prognoses were collected. Patients were followed up regarding postresection survival; overall and disease-specific survival rates were estimated by the Kaplan-Meier method with a log-rank test, and prognostic factors were evaluated by Cox regression. LNM incidence in early SRCC was 16.0% (37/231) overall: 6.9% (8/116) and 25.2% (29/115) in patients with pure and mixed SRCC, respectively. Univariate and multivariate analyses revealed SM2 invasion (odds ratio [OR]=5.070, P=0.003), lymphovascular invasion (LVI) (OR=14.876, P<0.001), pathologic pattern of mixed SRCC (OR=3.226, P=0.026), ulcer presence (OR=3.340, P=0.019) and lesion size over 20 mm (OR=2.823, P=0.015) as independent risk factors for LNM. Compared with pure SRCC, the mixed subtype was associated with older age, larger lesion size, higher LVI frequency, more frequent perineural invasion, and most importantly, higher LNM incidence. Patients with pure SRCC showed significantly longer overall survival (P=0.004) and disease-specific survival (P=0.002) than mixed SRCC patients. Pathologic subtype (hazard ratio [HR]=3.682; P=0.047), age (HR=5.246; P=0.001), SM1 invasion (HR=6.192; P=0.023), SM2 invasion (HR=7.529; P=0.021) and LNM (HR=5.352; P<0.001) were independent prognostic factors. Independent risk factors for LNM in early gastric SRCC were SM2 invasion, LVI, pathologic pattern, ulcer presence and lesion size over 20 mm. Early SRCC should be further classified by the purity of the SRC component.

S1 versus Doublet Regimens as Adjuvant Chemotherapy in Patients with Advanced Gastric Cancer after Radical Surgery with D2 Dissection-A Propensity Score Matching Analysis

BACKGROUND

Fluoropyrimidine- and platinum-based doublet regimen is the standard treatment of adjuvant chemotherapy (AC) for gastric cancer (GC). Our study aims to compare S1 with doublet regimens as AC in patients with advanced GC after radical surgery with D2 dissection.

METHODS

Patients who were diagnosed with GC and underwent a curative surgery with D2 dissection followed by AC were enrolled into our study. A propensity score matching analysis was performed to reduce the selection bias. Kaplan-Meier curves were estimated for recurrence-free survival (RFS) and overall survival (OS). Cox regression models were conducted for survival.

RESULTS

After propensity sore matching, 64 patients with S1 and 64 patients with doublet regimens were identified. The median RFS (p = 0.355) and OS (p = 0.309) were both insignificant between S1 and ST. Cox regression analysis demonstrated that pathologic stage and lymph node ratio (LNR) were independently correlated with survival. Patients were then stratified into low risk and high risk groups. The median RFS (p < 0.001) and OS (p < 0.001) had significant differences between low risk and high risk. In the high-risk group, doublet regimens were strongly associated with survival (p = 0.020) as compared with S1. While in the low-risk group, doublet regimen and S1 did not have statistically different survival benefits.

CONCLUSIONS

Our study demonstrated that doublet regimens are superior to S1 in high-risk groups, and that survival outcomes are similar between doublet regimens and S1 in low-risk groups. Our prognostic model might have clinical implications for AC.

Prognosis factors of advanced gastric cancer according to sex and age

BACKGROUND

Gastric cancer has a relatively high prevalence and is one of the most common causes of cancer-related death worldwide. However, the prognosis for gastric cancer remains poor, especially in the advanced stages, despite many improvements in diagnosis and treatment.

AIM

To evaluate the outcomes regarding advanced gastric cancer development according to sex and age.

METHODS

We retrospectively reviewed 2005 patients who underwent curative gastrectomy for advanced gastric cancer between 2002 and 2007 at a single Korean centre. Prognosis and risk factors for nodal involvement were evaluated according to sex and age.

RESULTS

In this retrospective cohort study, we examined the cases of 2005 patients [sex, 1384 men (69%), 621 women (31%)] with advanced gastric cancer. The patients’ age range was 22-87 years (mean age: 57.7 ± 12.3 years), with approximately 53.3% of the patients being ≤ 60 years old. Based on a Cox proportional hazards model, overall survival was independently predicted by older age, larger tumour size, lymphovascular invasion, lymph node metastasis, deeper tumour invasion, moderately-to-poorly differentiated tubular adenocarcinoma, and signet ring cell carcinoma. The same model revealed that relapse-free survival was independently predicted by advanced age, larger tumour size, lymphovascular invasion, deeper tumour invasion, poorly differentiated tubular adenocarcinoma, and signet ring cell carcinoma.

CONCLUSION

Among patients with advanced gastric cancer, older age independently predicted poor overall survival and relapse-free survival. However, there were no significant sex-based differences in relapse-free and overall survival.

Poorly differentiated is more significant than signet ring cell component for lymph node metastasis in mixed-type early gastric cancer: a retrospective study from a large-volume hospital

Objective

The purpose of this study was to explore the role of different undifferentiated components in the lymph node metastasis (LNM) of early mixed gastric cancer.

Methods

A total of 1596 patients with EGC who underwent gastrectomy were divided into four types: pure differentiated (PD), pure poorly differentiated (Poorly D), pure signet ring cell carcinoma (SRC), and mixed. Mixed type was classified into four subtypes: differentiated-predominant type mixed with poorly differentiated component (MD-P), poorly differentiated-predominant type mixed with differentiated component (MP-D), differentiated-predominant type mixed with SRC component (MD-S), and poorly differentiated-predominant type mixed with SRC component (MP-S). We analyzed the clinicopathological differences between all types and the rates of LNM of patients fulfilling endoscopic submucosal dissection (ESD) criteria.

Results

LNM was more common in mixed (21.9%) than in PD (7.5%, P < 0.001) or SRC (11.3%, P < 0.001). When analyzed the subgroups of mixed type, LNM was more frequent in MD-P (15.4%) than in PD (7.5%, P = 0.003). LNM in MD-S (7.4%, P = 1.000) was not higher than in PD. MP-S (24.5%) showed a higher rate of LNM than SRC (11.3%, P < 0.001) rather than Poorly-D (22.7%, P = 0.681). For lesions satisfying ESD criteria, MD-S (0%, P = 1.000), and MD-P (5.9%, P = 0.12) did not have higher rates of LNM than PD (1.4%).

Conclusion

The presence of poorly differentiated component but not SRC increases the LNM rate of mixed type. ESD is recommended for the treatment of MD-S and MD-P consistent with ESD criteria.

Clinicopathological Evaluation of Gastric Signet Ring Cell Carcinoma: Our Experience

Aim

Gastric cancer is one of the most common cancers worldwide. In Turkey, stomach cancer is ranked 5th among men and 8th among women in all cancers and is located in the forefront in cancer-related deaths. Signet ring cell adenocarcinoma, which is the histopathological subtype of gastric cancer, has a poor prognosis. The incidence of signet ring cell adenocarcinoma is rising. In the present study, we aimed to describe the clinicopathologic features of signet ring cell adenocarcinoma.

Materials and Methods

A total of 79 patients with 30 being female (38%) and 49 male (62%) who were diagnosed with gastric signet ring cell adenocarcinoma in the Medical Oncology Department of Ankara Numune Training and Research Hospital between January 2004 and October 2015 were retrospectively evaluated.

Results

The baseline demographic characteristics of the patients, such as tumor localization, tumor stage, preoperative serum tumor markers, and treatment type (surgery and chemotherapy regimen), and the effects of these variables on survival and mortality were evaluated. Total surgery, stage III disease, moderate to poor grade, preoperative serum CA 19-9 and CEA levels were found as independent predictors of progression risk (p < 0.05). Each 1 ng/mL increase in preoperative serum CEA level was found to increase the risk of progression by 1.20 folds. Again, each 1 U/mL in preoperative serum CA 19-9 level was found to increase the risk of progression and mortality by 1.06 folds.

Conclusion

The clinicopathologic features of signet ring cell stomach cancer were described. Tumor localization and disease, CA 19-9 and CEA levels, and treatment type (surgery and chemotherapy regimen) were effective on survival and mortality. However, further studies with larger patient groups are needed on this issue.

How to cite this article

Altay SB, Akkurt G, Yılmaz N, et al. Clinicopathological Evaluation of Gastric Signet Ring Cell Carcinoma: Our Experience. Euroasian J Hepato-Gastroenterol 2020;10(2):76–84.

Possible indication of endoscopic resection in undifferentiated early gastric cancer

Endoscopic resection for early gastric cancer (EGC) without lymph node metastasis may be a valuable treatment option. To date, endoscopic resection for undifferentiated EGC is being investigated. We evaluated the risk of lymph node metastasis in undifferentiated EGC by examining the preoperative endoscopic findings and operated pathologic specimen. The medical records of patients who underwent surgical resection because of undifferentiated EGC between November 2008 and December 2015 were reviewed retrospectively. The risk factors associated with lymph node metastasis and the lymph node metastasis rate in the expanded indication of undifferentiated EGC were evaluated. A total of 376 patients with undifferentiated EGC (233 signet ring cell type and 143 poorly differentiated type) were analyzed. Lymph node metastasis was found in 9.8% of the patients. Among the patients who met the expanded criteria (59 patients), only one patient had lymph node metastasis (signet ring cell type without ulceration and 15 mm in size). The risk factors associated with lymph node metastasis were lesion size >20 mm (OR 3.013), scar deformity (OR 2.248), surface depression (OR 2.360), submucosal invasion (OR 3.427), and lymphovascular invasion (OR 6.296). Before endoscopic resection of undifferentiated EGC, careful selection of patients should be considered. The undifferentiated EGC with size ≥15 mm, scar deformity, surface depression, submucosal invasion, and lymphovascular invasion should be considered surgical resection instead of endoscopic resection.

Identification of biomarkers associated with histological grade and prognosis of gastric cancer by co-expression network analysis

The biological characteristics and clinical outcomes of gastric cancer (GC) are largely dependent on the histopathological type and degree of differentiation. The identification of the molecular mechanisms underlying the histological grade of GC may provide information about tumorigenesis and tumor progression, and may subsequently be used to develop novel therapeutic agents. The present study obtained the RNA sequencing data and clinical characteristics of patients with GC from The Cancer Genome Atlas. A total of 1,400 differentially expressed genes (DEGs) were screened between two histological grades. Weighted gene co-expression network analysis (WGCNA) was subsequently used to identify nine co-expressed gene modules, and the black module was found to be the most significant for prognosis prediction of tumor. Additionally, the black module was associated with overall survival time, death event, N stage and tumor-node-metastasis (TNM) stage. Functional enrichment analysis revealed that the biological processes of the genes in the black module included ‘Wnt signaling pathway’ and ‘structural molecule activity’. Additionally, 10 network hub genes that were significantly associated with the progression of GC were identified from the black module, and the significance of each hub gene was determined across different TNM stages. Kaplan-Meier survival curves revealed that keratin 40 and glycine decarboxylase were significantly associated with patient prognosis (P<0.05), suggesting that these genes may serve as potential progression and prognosis biomarkers in GC. The present study identified molecular markers that correlated with histological grade in GC. Therefore, the results obtained in the present study may have important clinical implications on treatment selection, risk stratification and prognosis prediction in patients with GC.

Effect of double-layer structure in intramucosal gastric signet-ring cell carcinoma on lymph node metastasis: a retrospective, single-center study

BACKGROUND

Among all types of gastric cancer (GC), signet-ring cell carcinoma (sig-GC) accounts for 4-17% of cases. The prognosis of early sig-GC is relatively good, with the 5-year survival rate at 99.7%. However, the correlation between histological features and lymph node metastasis (LNM) among pT1a (M) sig-GC remains unclear. Sig-GC often exhibits a double-layer structure (DLS) in the intramucosal layer, demonstrating functional differentiation into the normal gastric gland. Assumedly, the loss of the differentiation makes the DLS deranged, accounting for the occurrence of submucosal invasion and LNM. This study aimed to assess the proportion of DLS, to elucidate the correlation between histological features (including DLS) and LNM status, and to determine the LNM-negative condition in pT1a (M) sig-GC.

METHODS

We reviewed the pathological data of 310 patients with 310 intramucosal sig-GCs who received gastrectomy with lymph node dissection. Immunohistochemistry was performed on all specimens to evaluate the presence of DLS. Furthermore, we review the clinicopathological features, including tumor size, lymphovascular invasion (LVI), ulceration (UL), and DLS results, and then statistically analyze the correlation between these features and LNM status.

RESULTS

Overall, 129 pT1a (M) sig-GCs (42%) were DLS present. The univariate analysis revealed that "Tumor size > 20 mm", "UL present", and "DLS absent" were significant risk factors of LNM. The multivariate logistic regression analysis revealed only "DLS absent" as statistically significant.

CONCLUSIONS

"DLS absent" is a risk factor of LNM detected by the multivariate analysis. In pT1a (M), LVI absent, UL absent, tumor size > 20 mm, sig-GC, no LNM occurred in "DLS present" cases.

Comparable rates of lymph node metastasis and survival between diffuse type and intestinal type early gastric cancer patients: a large population-based study

BACKGROUND AND AIMS

Limited evidence and contradictory results exist regarding the impact of Lauren type, namely diffuse and intestinal types, of lymph node metastasis (LNM) and prognosis for early gastric cancer (EGC). We aimed to compare LNM and prognosis between diffuse and intestinal type EGCs using comprehensive statistical analysis.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify all patients with surgically resected, histologically diagnosed, intestinal or diffuse type EGC. Multivariate logistic regression, multivariate Cox regression, multivariate competing risk model, and propensity score matching were used to analyze association the Lauren type and LNM or prognosis.

RESULTS

We identified 5593 EGCs from the SEER database, including 4376 intestinal types and 1217 diffuse types. No positive association was found between LNM and Lauren type (odds ratio, .93; 95% confidence interval [CI], .70-1.24; P = .62) after adjustment for other risk factors. Moreover, diffuse-type EGCs showed a similar prognosis to intestinal type EGCs in both multivariate Cox regression (HR [hazard ratio], .95; 95% CI, .77-1.18; P = .66) and the multivariate competing risk model (subdistribution HR [SHR], .99; 95% CI, .80-1.22; P = .926). Propensity score matching was used, and 733 diffuse types were matched with 733 intestinal types. We did not find any association between the Lauren type and LNM (odds ratio, .98; 95% CI, .71-1.37; P = .934) or prognosis in the univariate Cox regression (HR, .98; 95% CI, .76-1.26; P = .893) and univariate competing risk model (SHR, .98; 95% CI, .76-1.26; P = .893).

CONCLUSIONS

Diffuse-type EGC may have a comparable risk of LNM and prognosis to intestinal-type EGC. Nevertheless, these results should be carefully interpreted with caution when choosing endoscopic resection instead of surgery, because the treatment choice for EGC depends on the risk of lymphovascular invasion rather than LNM rate or prognosis.

State of the art for gastric signet ring cell carcinoma: from classification, prognosis, and genomic characteristics to specified treatments

Gastric cancer (GC) is responsible for 9% of cancer deaths worldwide. Over 950,000 new cases are diagnosed each year, and about 90% of them are in advanced stage, requiring chemotherapy. In Europe there has been research based on pre- and postoperative chemotherapy treatment, using 5-fluorouracil, epirubicin, cisplatin, capecitabine, and docetaxel. Chemotherapy significantly impairs the quality of life of patients; however, the final effects are not always satisfactory. There is scientific evidence that gastric mucus tumors and signet ring cell carcinomas have a pattern of specific signatures, that distinguish them from other gastric cancer subtypes, and may be associated with a poor response to systematic treatment. Signet ring cell carcinoma is less chemosensitive than others, and the increase in the percentage of signet ring cells correlates with resistance to chemotherapy. Perioperative chemotherapy in advanced signet ring cell carcinomas is an independent factor of poor prognosis and survival, which is explained by the toxicity of neoadjuvant treatment. Therefore, curative surgical resection enhanced by standardized lymphadenectomy remains the recommended gold standard in GC therapy. According to presented studies, early detection and aggressive treatments for this subtype of GC is a reasonable approach. This review paper is mostly addressed to physicians who are interested in updating to the state of the art concerning different subtypes of gastric carcinoma.

Risk of lymph node metastasis in undifferentiated-type mucosal gastric carcinoma

BACKGROUND

Endoscopic resection (ER) has come to be recognized as a standard treatment for early gastric cancer (EGC). While its adoption is expanding, ER remains restricted to cases of EGC without lymph node metastasis for the treatment of local resection. On the other hand, histopathological analyses of surgically resected specimens of EGC have revealed the presence of lymph node (LN) metastasis in some cases of mucosal gastric cancer (MGC) and undifferentiated MGC (UD-MGC) is considered to have higher risk of nodal metastases than differentiated MGC (D-MGC). To evaluate the risk factors for LN metastasis in MGC, we investigated the characteristics of UD-MGC associated with LN metastasis.

METHODS

Among all UD-MGC patients who underwent surgery as initial treatment, between January 2000 and March 2016, we reviewed the clinicopathological data, including the preoperative endoscopic findings and histopathological findings in the resected specimens, of the 11 UD-MGC patients who were identified as having lymph node metastasis. Furthermore, in comparison with cases without lymph node metastasis, we examined the possibility of expansion of the indication for local treatment.

RESULTS

In most of the cases of UD-MGC with LN metastasis, the lesions were relatively large (> 20 mm in diameter) and of the clearly depressed type with faded color and apparent border, and histopathology revealed a high percentage of cases with lymphatic invasion and a predominance of signet ring cell carcinomas. No cases with LN metastasis without depressed macroscopic type nor signet ring cell carcinoma component existed. A degree of invasion of lamina propria (LP) or muscularis mucosae (MM) had same relation to the risk of LN metastasis.

CONCLUSIONS

In this study, none of the cases of undifferentiated-type mucosal cancer (UD-MGC) with LN metastasis satisfied the current adoption criteria for ER. We suggested significant risk factors for LN metastasis in UD-MGC cases as depressed tumor type, presence of a signet ring cell carcinoma component, presence of lymphatic tumor invasion, and a large tumor size. More detailed analyses of the endoscopic and histopathological findings may allow further risk classification for LN metastasis in cases of UD-MGC.

Risk Factors of Lymph Node Metastasis in Patients with Early Pure and Mixed Signet Ring Cell Gastric Carcinomas

Background: Early gastric carcinoma (EGC) with pure signet ring cell carcinoma (pSRCC) has been reported to have favourable prognosis and low risk of lymph node metastasis (LNM). However, risk factors of LNM and clinicopathological features for early gastric mixed signet ring cell carcinoma (mSRCC) remain poorly investigated. The aim of this study was to identify risk factors of LNM and compare clinicopathological characteristics and prognosis of early gastric pSRCC with mSRCC.

Methods: This retrospective study was conducted at our center between 2005 and 2015 in 796 patients underwent radical gastrectomies combined with lymph node dissections, A total of 160 patients with early gastric SRCC underwent gastrectomies with lymph node dissections were reviewed, in which 79 cases were pSRCC and 81 cases were mSRCC. Risk factors of LNM and clinicopathologic features of these two groups were statistically compared, including age, gender, tumor location, gross pattern, size, invasion depth, lymphovascular invasion (LVI), helicobacter pylori (Hp) infection, atrophic gastritis, ulcer finding and LNM. Patients were follow-up for post-resection survival. The 5-year survival and disease-specific survival rate were estimated with the Kaplain-Meier method with a log-rank test and compared between the two groups.

Results: Tumor size (P<0.05), invision depth (P<0.05) and LVI (P < 0.0001) were risk factors of LNM, LVI (P < 0.0001) was independent risk factor of LNM in 160 patients. Univariate analysis reviewed LVI (P < 0.0001) as the risk factor in the pSRCC group, and the risk factors of LNM in the mSRCC included LVI (P < 0.0001) and tumor size (P<0.05). Multivariable analysis revealed two independent risk factors in the mSRCC group: 1) tumor size (P < 0.05), and 2) LVI (P < 0.0001). The significant characteristics in two groups included the male gender (P < 0.0001), gross pattern (P < 0.05), LVI (P < 0.01), and Hp infection (P < 0.01). The difference of LNM rate between expanded indication and out of indication in 160 patients was significant (P=0.03). The overall 5-year survival rate for early gastric SRCC was 96.3%. There was no significant difference in the overall survival and disease-specific survival between the two groups.

Conclusions: Although with similar post-resection survival, the independent risk factors of LNM in the early mSRCC group, compared to those in the early pSRCC group, included large tumor size and LVI. Early gastric mSRCC had more aggressive clinicopathological features than pSRCC.

Risk Factors for Lymph Node Metastasis in Undifferentiated-Type Gastric Carcinoma

Undifferentiated-type carcinoma has a high incidence of lymph node metastasis. The independent risk factors for lymph node metastasis in undifferentiated-type carcinoma are invasion depth, tumor size, lymphovascular invasion, and presence of ulcer. In the cases that meet the curative resection criteria, no lymph node metastasis was observed in the Japanese studies, but some metastases were observed in Korean studies. After performing curative endoscopic submucosal dissection, the survival rate is similar to that of gastrectomy. The discrepancy between endoscopy and pathology is high in undifferentiated-type carcinoma. The tumor size in endoscopy is a significant risk factor for non-curative resection, and when the tumor size is small, the non-curative resection rate is significantly reduced. Lymphovascular invasion can be assessed in pathologic examination and D2-40 stain is helpful. The presence of ulcer should be determined by pathology, but ulcer's omission in pathology report makes the analysis difficult. Undifferentiatedtype carcinomas with differentiated-type components show higher lymph node metastasis rate than that of pure undifferentiatedtype carcinomas. The lymph node metastasis rate of signet ring cell type is lower than that of other undifferentiated-type carcinomas and is similar to differentiated-type carcinomas. The application of these additional histologic findings may improve the indication of endoscopic submucosal dissection.

Analysis of prognostic factors in patients with early gastric cancer based on SEER database

AIM

To identify the risk factors affecting the survival of patients with early gastric cancer (EGC).

METHODS

The patients who were diagnosed with T1 gastric cancer after operation were selected from the SEER database. The COX proportional hazards model, chi square test, and logistic regression were used to analyze the patients' data.

RESULTS

COX proportional risk model analysis showed that age, race, sex, tumor size, pathological type, degree of differentiation, and lymph node metastasis were independent prognostic factors for overall survival. Tumor size was not an independent risk factor for EGC in patients younger than 60 years of age. With regard to gender, race was an independent risk factor for male patients, but there was no difference among females. Tumor size and pathological type were risk factors for prognosis in males but not in females. The independent risk factors affecting lymph node metastasis were tumor size, pathological type, and degree of differentiation.

CONCLUSION

Age and gender are independent factors affecting the prognosis of EGC patients. There are also differences in risk factors affecting prognosis among different age groups and different gender groups. Understanding the risk factors for patients with different clinical characteristics can provide evidence-based medicine support for accurate treatment of EGC patients.

Mucinous adenocarcinoma and non-mucinous adenocarcinoma: differing clinicopathological characteristics and computed tomography features in gastric cancer

Mucinous gastric carcinoma (MGC) is a rare histological subtype of gastric cancer. The clinicopathological characteristics and CT features of MGC remain controversial. This study aimed to determine the clinicopathological characteristics and CT features of MGC. We reviewed 62 patients with MGC and 104 patients with non-mucinous gastric carcinoma (NMGC), pathologically confirmed between 2003 and 2015. There are significant differences in some clinicopathological characteristics and CT features between MGC and NMGC. NMGC occurs preferentially in males and more frequently in the lower third of the stomach. Patients with MGC were characterized by larger tumor size, more advanced tumor stages (II and III) and fewer lymphatic invasions. Layered enhancement (83.3%) was the main pattern of MGC, while the most common pattern in NMGC was homogeneous enhancement (52.6%), followed by heterogonous enhancement (34.6%). The degree of enhancement of the inner layer in MGC was significantly higher than in NMGC (ΔCT of portal venous phase: 54.57 Hu vs. 47.19 Hu, P = 0.034), while the middle or outer layer in MGC was significantly less enhanced (ΔCT of portal venous phase: 19.07 Hu vs. 33.09 Hu, P <0.001). Calcifications were more common in MGC (P <0.001). ROC curves revealed that the most effective variables in distinguishing MGC and NMGC were ΔCT of the middle or outer layer in the arterial phase (AUC=0.774) and portal venous phase (AUC=0.774), followed by the attenuation value of the middle or outer layer in the unenhanced phase (AUC=0.763). Calcifications had a high specificity (98.7%) in the diagnosis of MGC. The accuracy (86.1%), sensitivity (83.3%) and specificity (87.2%) of layered enhancement in diagnosing MGC were all high. Therefore, MGC was more likely to have larger tumor size and more advanced tumor stage (II and III) than NMGC. The thicker gastric wall, layered enhancement pattern and calcification were highly suggestive CT features for differentiating MGC from NMGC.

Incidence, Survival, and Predictors of Lymph Node Involvement in Early-Stage Gastric Signet Ring Cell Carcinoma in the US

INTRODUCTION

The incidence, survival, and propensity for nodal metastasis in early-stage gastric signet ring cell carcinoma have not been defined in the United States. These data are critical determinants for treatment allocation.

METHODS

Cases of gastric signet ring cell carcinoma were extracted from the national SEER database for the years 2004-2013. Age-standardized incidence was derived. Survival was calculated using the Kaplan-Meier method. Univariate and multivariate analyses were performed to identify predictors of nodal metastasis. Exclusion criteria included neoadjuvant radiotherapy and lack of histologic or nodal data.

RESULTS

A total of 10,624 cases were initially identified. The analysis cohort included 506 cases with early T-stage N0M0 disease following exclusions. The incidence was 0.094 per 100,000 person-years. The 5-year survival rate was 82.8%. Tumor stage (p < 0.001) and size (p < 0.001) were independent predictors of nodal metastasis. The incidence of nodal involvement for T1a tumors <2 cm was 5.4% (p < 0.004).

CONCLUSION

The incidence of potentially resectable signet ring gastric carcinoma has not changed significantly over the past decade. While presenting with predominantly high-grade histology, early T-stage disease has a high survival rate. Small T1a tumors have low rates of nodal metastasis, suggesting that an endoscopic resection could be considered in this subset.

Differences in clinicopathological characteristics and computed tomography findings between signet ring cell carcinoma and nonsignet ring cell carcinoma in early and advanced gastric cancer

Signet ring cell carcinoma (SRC) of the stomach is a histological type based on microscopic characteristics. SRC's clinicopathological characteristics and prognosis are still controversial. Our study is to describe the clinicopathological features and multidetector computed tomography (MDCT) findings of patients with SRC of the stomach in comparison with nonsignet ring cell adenocarcinoma (NSRC). We retrospectively analyzed data from 241 patients who had undergone curative gastrectomy, including 62 SRC and 179 NSRC. Clinicopathological outcomes and MDCT findings were evaluated, and we investigated whether these variables were correlated with histopathological type. In early gastric carcinoma, patients with SRC were younger (50.2 vs. 60.2 years; P = 0.000) and more likely to be observed in the middle and lower third stomach (P = 0.010). Early SRC had a tendency to be confined to the mucosa (82.1%). There were significant differences in degree of enhancement between early SRC and NSRC on MDCT imaging (P < 0.001). In advanced gastric carcinoma, SRC was more likely to be stage T3‐4 (100%). SRC patients had thicker tumors (P = 0.001) and a higher frequency of diffusely infiltrative gross appearance (P < 0.001). SRC was more likely to have high‐degree contrast enhancement than were NSRC (P = 0.001). The maximal diameter of SRC tumor on MDCT imaging correlated with lymph node metastasis (sensitivity 93.9%, specificity 74.1%) and serosal invasion (sensitivity 89.5%, specificity 78.0%) of SRC. In conclusion, SRC differs significantly from NSRC in clinicopathological features at presentation. MDCT could help differentiate advanced gastric SRC from NSRC based on the thickened stomach wall, high‐degree contrast enhancement, and a higher frequency of diffusely infiltrative gross appearance, particularly in combination.

Feasibility of differentiating T3 from T4a gastric cancer in different Lauren classification by determining serosa invasion: Diagnostic performance of high enhanced serosa sign

Objective

To study the value of high enhanced serosa sign on contrast-enhanced computed tomography (CT) in differentiating T3 from T4a gastric cancer in different Lauren classification.

Methods

This study included 276 consecutive patients with surgically confirmed pT3 or pT4a gastric cancers. The pre-operative CT images were reviewed by two radiologists blinded. The demonstration of the high enhanced serosa on CT between T3 and T4a was compared with chi-square test. The diagnostic performance of this sign on CT in the differentiation of T4a from T3 in different Lauren classification was calculated.

Results

The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the judgement of serosa invasion using the high enhanced serosa sign on CT was 74.6%, 63.7%, 83.6%, 76.0% and 73.8% by one radiologist and 76.4%, 66.1%, 84.9%, 78.1% and 75.4% by the other radiologist. Compared to the intestinal-type, the sensitivity of the judgement of serosa invasion using the high enhanced serosa sign on CT in diffuse-type was significant higher (80% in both readers), while the specificity trended to be lower (65.9% and 80.5%, respectively). There is no significant difference in the accuracy of diagnosis between intestinal-type and diffuse-type of gastric cancers (the P-values of two radiologists were 0.968, 0.591, respectively). The combination of the high enhanced serosa sign with conventional CT signs is significant different in diagnosis of T3 and T4a (P<0.001). The diagnostic accuracy was increased in both radiologists after the combination. The two readers achieved substantial agreement, with Kappa coefficient of 0.63, P<0.001.

Conclusions

The high enhanced serosa sign on CT is associated with serosa involvement. The sensitivity of the judgement of serosa invasion using this sign on CT in diffuse-type was significant higher than that in intestinal-type.

Gastric poorly cohesive carcinoma: a correlative study of mutational signatures and prognostic significance based on histopathological subtypes

AIMS

Genome-wide next-generation sequencing has revealed several driver mutations and has allowed the establishment of a molecular taxonomy of gastric cancer. However, there are few detailed studies on the mutational spectrum of poorly cohesive gastric carcinoma. Thus, this study aim to investigate its mutation profile based on clinicopathological characteristics.

METHODS AND RESULTS

Herein, we analysed the mutational pattern of 77 genes in a cohort of 91 patients with poorly cohesive carcinoma by using targeted sequencing, and evaluated the clinicopathological significance of the various mutations based on histological pattern, either signet ring cell (SRC) or other types of poorly cohesive carcinoma (not otherwise specified) (PCC-NOS). Panels of seven (PIK3CA, CDH1, PTEN, RHOA, HDCA9, KRAS, and ATM), three (PIK3CA, CTNNB1, and KRAS) and two (HDCA9 and IGF1R) genes were associated with a diffuse infiltrative growth pattern, lymphovascular invasion, and perineural invasion, respectively. Furthermore, PDGFRB mutations were associated with a favourable prognosis, whereas MET mutations were associated with a poor prognosis. The PCC-NOS-predominant type was associated with a greater depth of invasion, lymph node metastasis and poorer prognosis than the SRC-predominant type. Mutations in TP53, BRAF, PI3CA, SMAD4 and RHOA were associated with PCC-NOS. Interestingly, RHOA-mutated gastric cancers showed a distinct morphology, as they were characterised by a superficial SRC or tubular component and a deep invasive PCC-NOS component with desmoplasia.

CONCLUSIONS

Taken together, our findings demonstrate that gastric poorly cohesive carcinomas show several mutational patterns associated with specific clinicopathological characteristics, and particularly show distinct morphological findings when associated with RHOA mutation.

A new mutation of the CDH1 gene in a patient with an aggressive signet-ring cell carcinoma of the stomach

Germline mutations in CDH1, the gene coding for the E-cadherin adhesion protein, are known to cause hereditary diffuse gastric cancer. We identified a new truncating germline mutation (p.Asp538Thrfs*19) in exon 11 of the CDH1 gene in a 41-year-old male with a diffuse gastric cancer. Although he had no parental history of gastric cancer, the co-segregation study in the family detected the same mutation in his healthy 31-year-old brother. The mutation affects one of the extracellular repeat (CAD repeats) domains which is essential for the homophilic binding specificity that directs “E-cadherin” to bind with itself each others. In this case, immunohistochemical analysis showed no expression of E-cadherin in the tumor sample and was a useful prescreening tool to genetic testing. This finding was associated with a poor response to trastuzumab-based treatment.

Clinical application of early gastric carcinoma with lymphoid stroma based on lymph node metastasis status

BACKGROUND

Gastric carcinoma with lymphoid stroma (GCLS) is characterized by undifferentiated carcinoma mixed with prominent lymphoid infiltration. GCLS has unique clinicopathological features and a better prognosis compared to other types of gastric cancer. We analyzed the clinicopathological features of early GCLS in relation to lymph node metastasis (LNM).

METHODS

We performed a retrospective analysis of 241 patients diagnosed with GCLS confined to the mucosa or the submucosa between March 1998 and December 2015. Their data were compared with those from 1219 patients who underwent resection for differentiated early gastric cancer (EGC).

RESULTS

Of the 241 patients analyzed, 33 (13.7%) had intramucosal cancers and 208 (86.3%) had cancers that penetrated the submucosa. Compared to differentiated EGC, early GCLS was more prevalent in younger individuals and in men, tended to be proximally located, was highly associated with Epstein-Barr virus (EBV) infection (89.2%), and had a lower risk of LNM. The 5-year disease-specific survival rate of patients with early GCLS was 98.3% but depended significantly on LNM status (p < 0.001) and EBV infection status (p = 0.039). The risk of LNM from mucosal GCLS and submucosal GCLS was 0% [95% confidence interval (CI) 0-9.1] and 10% (95% CI 6.8-15.2), respectively. On multivariate analysis, LNM was found to be associated with tumor size (p = 0.022) and lymphovascular invasion (p = 0.002) in addition to tumor depth.

CONCLUSIONS

Early GCLS has distinct clinicopathological features depending on age, sex, tumor location, EBV infection status, and LNM status. Tailored therapies, including endoscopic treatment, are needed based on the distinct clinicopathological features of early GCLS.

Lymph Node Metastasis in Mucosal Gastric Cancer: Reappraisal of Expanded Indication of Endoscopic Submucosal Dissection

OBJECTIVE

To evaluate risk factors for lymph node (LN) metastasis in mucosal gastric cancer, particularly the effect of cellular differentiation, and implications for the indication of endoscopic submucosal dissection (ESD).

SUMMARY BACKGROUND DATA

The indication of ESD has been expanded to undifferentiated-type (UD-type) gastric cancer despite risk of LN metastasis.

METHODS

Patients who underwent radical gastrectomy for pT1a stage primary gastric adenocarcinoma between 2008 and 2012 were retrospectively analyzed. We evaluated risk factors of LN metastasis using univariate and multivariate analyses. Pathologic slides of primary tumor and metastatic LNs from LN positive patients were reviewed.

RESULTS

A total of 1003 mucosal gastric cancer patients were enrolled, and mean number of retrieved LNs was 35.5. Eighteen (1.8%) among them had LN metastasis: 2 of the 502 differentiated-type (D-type) patients and 16 of the 501 UD-type patients (0.4% vs 3.2%, P < 0.001). Type of cellular differentiation was a significant risk factor for LN metastasis in univariate and multivariate analyses. Of 216 UD-type patients satisfying the expanded indication of ESD, 5 patients (2.3%) showed LN metastasis. Despite more aggressive clinical features such as larger size of tumor and more LN metastasis, the UD-type cancer showed a less invasion into the muscularis mucosae layer than the D-type cancer.

CONCLUSIONS

Because UD-type cancer is a risk factor for LN metastasis in mucosal gastric cancer, ESD cannot be concluded to be a better option than surgery in all UD-type cancer patients. Redefinition of the expanded indication of ESD is required.

A Risk-prediction Model Based on Lymph-node Metastasis for Incorporation Into a Treatment Algorithm for Signet Ring Cell-type Intramucosal Gastric Cancer

OBJECTIVE

The aim of the study was to develop a reliable and easy-to-use risk-scoring system (RSS) to predict lymph-node metastasis (LNM) and determine the feasibility of endoscopic submucosal dissection for mucosa-confined signet ring cell carcinomas (SRCs).

BACKGROUND

Fewer LNM and better survival rates have been reported for early gastric SRCs compared with other undifferentiated early gastric cancers (EGCs).

METHODS

Data from 1544 patients with mucosa-confined SRCs were reviewed. Stepwise logistic regression analysis determined the independent predictors of LNM. Risk scores were based on the final predictive factors for LNM, and performance was internally validated using a split-sample approach. External validation was also performed in an independent dataset (n = 208) to assess the discriminatory power of the RSS.

RESULTS

The overall LNM incidence was 3.8% (57/1544). Three risk factors (tumor size ≥1.7 cm, tumors of elevated type, and lymphatic-vascular involvement) were significantly associated with LNM. These factors were incorporated into the RSS, and were assigned scores ranging from 0 to 4. The area under the receiver-operating characteristic curve for predicting LNM after internal and external validation was 0.68 (95% confidence interval, 0.0793-0.2865) and 0.686 (95% confidence interval, 0.618-0.748), respectively. A score of 2 points was the optimal cut-off value for LNM prediction, and the overall diagnostic accuracy was 96%. LNM were found in 2.9% and 23.8% of the low and high-risk groups of the RSS, respectively.

CONCLUSIONS

A RSS may help to predict LNM and evaluate endoscopic submucosal dissection feasibility in patients with intramucosal SRC.

Progress in research of gastric signet ring cell carcinoma

Gastric signet ring cell carcinoma is a special type of gastric cancer. In recent years the incidence of gastric cancer has decreased, but the incidence of gastric signet ring cell carcinoma is still rising. Although a large number of studies reported the clinicopathologic features and oncogenesis of gastric signet ring cell carcinoma, the results are inconsistent. This article mainly discusses the clinicopathologic features, prognosis, and molecular characteristics of oncogenesis of gastric signet ring cell carcinoma to provide a basis and strategy for individualized treatment of this malignancy.

Differences in the prognosis of early gastric cancer according to sex and age

BACKGROUND

Few studies have compared early gastric cancer (EGC) outcomes according to sex and age.

METHODS

We retrospectively reviewed 2085 patients who underwent curative gastrectomy for EGC between 1989 and 2000. Prognosis and risk factors for nodal involvement were evaluated according to sex and age.

RESULTS

Male sex and age were independent prognostic factors for overall survival (OS) but not relapse-free survival (RFS). In young (⩽55 years) patients, there were no significant differences in RFS and OS between men and women. However, older (>55 years) men had a poorer OS and older women had a poorer RFS. Young female patients had a higher proportion of gastric cancer-related death than young male patients. Female sex was an independent risk factor for nodal involvement in younger patients.

CONCLUSIONS

Young women with EGC should be more intensively treated and monitored than other patient groups and should not be treated by endoscopic resection.

Applicability of endoscopic submucosal dissection for undifferentiated early gastric cancer: Mixed histology of poorly differentiated adenocarcinoma and signet ring cell carcinoma is a worse predictive factor of nodal metastasis

BACKGROUND

Endoscopic submucosal dissection (ESD) is not considered an appropriate treatment for undifferentiated early gastric cancer (UEGC) due to the higher risk of nodal metastases. We aimed to investigate predictive factors for nodal metastases in UEGCs, determine whether the tumor histology is an independent factor for it, and explore whether ESD is applicable for UEGC.

METHODS

We reviewed the medical records of 1837 patients who underwent curative gastrectomy for poorly differentiated adenocarcinoma, signet ring cell carcinoma, and a mixed type of both tumors between 2008 and 2012.

RESULTS

Nodal metastases were found in 208 (11.3%) patients. Multivariate analysis revealed that lymphovascular invasion and tumor histology were significantly associated with nodal metastases in mucosal cancers, the rates of which were higher in mixed type tumors (6.3%) than in the other two types (2.0-2.5%; p = 0.005). No nodal metastases were observed in poorly differentiated adenocarcinomas <2 cm and signet ring cell carcinomas <1 cm without lymphovascular invasion and confined to the mucosa.

CONCLUSION

Mixed type tumors should not be considered for endoscopic resection. ESD might be applicable for mucosal tumors with poorly differentiated adenocarcinoma <2 cm and signet ring cell carcinoma <1 cm without lymphovascular invasion.

Dynamic contrast-enhanced MRI of gastric cancer: Correlations of the pharmacokinetic parameters with histological type, Lauren classification, and angiogenesis

PURPOSE

To compare the pharmacokinetic parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in gastric cancers of different histological type and Lauren classification, and to investigate whether DCE-MRI parameters correlate with vascular endothelial growth factor (VEGF) expression levels in gastric cancer.

METHODS

Included were 32 patients with gastric cancer who underwent DCE-MRI of the upper abdomen before tumor resection. DCE-MRI parameters including the volume transfer coefficient (K^trans), reverse reflux rate constant (K_ep), and extracellular extravascular volume fraction (V_e) were calculated from the tumor region. Post-operative specimens were used for determination of histological differentiation (i.e., non-mucinous, mucinous, or signet-ring-cell adenocarcinoma) as well as Lauren classification (intestinal type or diffuse type). VEGF expression was examined for assessing angiogenesis. DCE-MRI parameters with different histological type and Lauren classification were compared using independent samples t-test and analysis of variance, respectively. Correlations between DCE-MRI parameters and VEGF expression grades were tested using Spearman correlation analysis.

RESULTS

Among gastric adenocarcinomas of three different histological types, mucinous adenocarcinomas showed a higher V_e and lower K^trans than the others (P<0.01). Between the two Lauren classifications, the diffuse type showed a higher V_e than the intestinal type (P<0.001). The mean K^trans showed a significantly positive correlation with VEGF (r=0.762, P<0.001).

CONCLUSION

DCE-MRI permits noninvasive prediction of tumor histological type and Lauren classification and estimation of tumor angiogenesis in gastric cancer. DCE-MRI parameters can be used as imaging biomarkers to predict the biologic aggressiveness of a tumor as well as patient prognosis.

Prediction of lymph node metastasis and sentinel node navigation surgery for patients with early-stage gastric cancer

Accurate prediction of lymph node (LN) status is crucially important for appropriate treatment planning in patients with early gastric cancer (EGC). However, consensus on patient and tumor characteristics associated with LN metastasis are yet to be reached. Through systematic search, we identified several independent variables associated with LN metastasis in EGC, which should be included in future research to assess which of these variables remain as significant predictors of LN metastasis. On the other hand, even if we use these promising parameters, we should realize the limitation and the difficulty of predicting LN metastasis accurately. The sentinel LN (SLN) is defined as first possible site to receive cancer cells along the route of lymphatic drainage from the primary tumor. The absence of metastasis in SLN is believed to correlate with the absence of metastasis in downstream LNs. In this review, we have attempted to focus on several independent parameters which have close relationship between tumor and LN metastasis in EGC. In addition, we evaluated the history of sentinel node navigation surgery and the usefulness for EGC.

Early signet ring cell carcinoma of the stomach is related to favorable prognosis and low incidence of lymph node metastasis

BACKGROUND

The aim of this study was to evaluate the clinical characteristics of early signet ring cell carcinoma of the stomach (SRC) and to investigate the optimal treatment strategy for early SRC.

METHODS

A total of 746 patients with pT1 gastric cancer (GC), who had undergone surgical resection between 1997 and 2012 were analyzed. Of these, 190 patients with SRC were enrolled in this study.

RESULTS

(i) The patients with SRC showed a significantly longer overall survival (P = 0.012) and disease free survival (P = 0.004) than patients with the other histological types. Multivariate analysis identified SRC as an independent factor predicting favorable prognosis in pT1 GC (HR = 0.38; 95% CI: 0.11-0.96; P = 0.041). Specifically, in undifferentiated pT1 GC, SRC was significantly less associated with lymph node metastasis (LNM) (OR = 0.39; 95% CI: 0.15-0.96; P = 0.042). (ii) From the viewpoint of a histological mixed-type, pure-SRC with pT1a was not associated with LNM regardless of tumor size (0.0%, 0/110), whereas mixed-SRC was an independent risk factor for LNM (OR = 7.19; 95% CI: 1.51-43.9; P = 0.012).

CONCLUSIONS

Patients with early SRC have a favorable prognosis with a low incidence of LNM. However, care should be taken with mixed-SRC, which consists of SRC and other histological types. J. Surg. Oncol. 2016;114:607-612. © 2016 Wiley Periodicals, Inc.

Novel Method for Differentiating Histological Types of Gastric Adenocarcinoma by Using Confocal Raman Microspectroscopy

Gastric adenocarcinoma, a single heterogeneous disease with multiple epidemiological and histopathological characteristics, accounts for approximately 10% of cancers worldwide. It is categorized into four histological types: papillary adenocarcinoma (PAC), tubular adenocarcinoma (TAC), mucinous adenocarcinoma (MAC), and signet ring cell adenocarcinoma (SRC). Effective differentiation of the four types of adenocarcinoma will greatly improve the treatment of gastric adenocarcinoma to increase its five-year survival rate. We reported here the differentiation of the four histological types of gastric adenocarcinoma from the molecularly structural viewpoint of confocal Raman microspectroscopy. In total, 79 patients underwent laparoscopic or open radical gastrectomy during 2008-2011: 21 for signet ring cell carcinoma, 21 for tubular adenocarcinoma, 14 for papillary adenocarcinoma, 6 for mucinous carcinoma, and 17 for normal gastric mucosas obtained from patients underwent operation for other benign lesions. Clinical data were retrospectively reviewed from medical charts, and Raman data were processed and analyzed by using principal component analysis (PCA) and linear discriminant analysis (LDA). Two-dimensional plots of PCA and LDA clearly demonstrated that the four histological types of gastric adenocarcinoma could be differentiated, and confocal Raman microspectroscopy provides potentially a rapid and effective method for differentiating SRC and MAC from TAC or PAC.

Prognostic Impact of the Signet Ring Cell Type in Node-Negative Gastric Cancer

Little is known regarding the prognostic impact of the signet ring cell (SRC) histotype on negative lymph nodes (LNs) in gastric cancer (GC). In this study, we aimed to investigate the differences between SRC and non-SRC GC patients without LN metastasis. The medical records of patients with GC who underwent gastrectomy at Sun Yat-Sen University Cancer Centre from 1996 to 2012 were reviewed to analyse the clinicopathologic characteristics associated with survival. A total of 480 cases of GC patients without LN metastasis were identified, which included 90 SRC GC patients and 390 non-SRC GC patients. Between the two groups, there were a host of significant differences in the American Joint Committee on Cancer, 7th edition (AJCC) stage. We found that SRC histology was correlated with a poor prognosis in terms of recurrence in node-negative GC patients and that SRC histologic analysis combined with AJCC staging maybe an effectual method for prediction of the recurrence rate. Additionally, we found that SRC GC presents a more dismal overall prognosis in patients with perineural or vascular invasion.

Assessment of histological differentiation in gastric cancers using whole-volume histogram analysis of apparent diffusion coefficient maps

PURPOSE

To investigate the efficacy of histogram analysis of the entire tumor volume in apparent diffusion coefficient (ADC) maps for differentiating between histological grades in gastric cancer.

MATERIALS AND METHODS

Seventy-eight patients with gastric cancer were enrolled in a retrospective 3.0T magnetic resonance imaging (MRI) study. ADC maps were obtained at two different b values (0 and 1000 sec/mm² ) for each patient. Tumors were delineated on each slice of the ADC maps, and a histogram for the entire tumor volume was subsequently generated. A series of histogram parameters (eg, skew and kurtosis) were calculated and correlated with the histological grade of the surgical specimen. The diagnostic performance of each parameter for distinguishing poorly from moderately well-differentiated gastric cancers was assessed by using the area under the receiver operating characteristic curve (AUC).

RESULTS

There were significant differences in the 5^th , 10^th , 25^th , and 50^th percentiles, skew, and kurtosis between poorly and well-differentiated gastric cancers (P < 0.05). There were correlations between the degrees of differentiation and histogram parameters, including the 10^th percentile, skew, kurtosis, and max frequency; the correlation coefficients were 0.273, -0.361, -0.339, and -0.370, respectively. Among all the histogram parameters, the max frequency had the largest AUC value, which was 0.675.

CONCLUSION

Histogram analysis of the ADC maps on the basis of the entire tumor volume can be useful in differentiating between histological grades for gastric cancer.

LEVEL OF EVIDENCE

4 J. Magn. Reson. Imaging 2017;45:440-449.

Risk of lymph node metastasis in mixed-type early gastric cancer determined by the extent of the poorly differentiated component

AIM: To predict the rate of lymph node (LN) metastasis in diffuse- and mixed-type early gastric cancers (EGC) for guidelines of the treatment.

METHODS: We reviewed 550 cases of EGC with diffuse- and mixed-type histology. We investigated the clinicopathological factors and histopathological components that influence the probability of LN metastasis, including sex, age, site, gross type, presence of ulceration, tumour size, depth of invasion, perineural invasion, lymphovascular invasion, and LN metastasis status. We reviewed all slides and estimated the proportions of each tumour component; pure diffuse type, mixed-predominantly diffuse type (diffuse > intestinal type), mixed-predominantly intestinal type (intestinal > diffuse type), and mixed diffuse = intestinal type. We calculated the extents of the respective components.

RESULTS: LN metastasis was observed in 12.9% (71/550) of early gastric cancers cases [15/288 mucosal EGCs (5.2%) and 56/262 submucosal EGCs (21.4%)]. Of 550 cases, 302 were diffuse-type and 248 were mixed-type EGCs. Of 248 mixed-type EGCs, 163 were mixed-predominantly diffuse type, 82 were mixed-predominantly intestinal type, and 3 were mixed diffuse = intestinal type. Mixed-type cases with predominantly diffuse type histology showed a higher frequency of LN metastasis (20.2%) than cases of pure diffuse type (9.3%) and predominantly intestinal type (12.2%) histology. We measured the dimensions of each component (intestinal and diffuse type) to determine the association of the extent of each component with LN metastasis in mixed-type gastric carcinoma. The total tumour size and the extent of poorly differentiated components was associated with LN metastasis, while that of signet ring cell components was not.

CONCLUSION: We recommend careful identification and quantitative evaluation of mixed-type early gastric cancer components after endoscopic resection to determine the intensity of the treatment.

Difficulty of predicting the presence of lymph node metastases in patients with clinical early stage gastric cancer: a case control study

BACKGROUND

The relationship between pathological factors and lymph node metastasis of pathological stage early gastric cancer has been extensively investigated. By contrast, the relationship between preoperative factors and lymph node metastasis of clinical stage early gastric cancer has not been investigated. The present study was to investigate discrepancies between preoperative and postoperative values.

METHODS

From January 2011 to December 2013, 1042 patients with clinical stage early gastric cancer who underwent gastrectomy with lymphadenectomy were enrolled. Preoperative and postoperative values were collected for subsequent analysis. Receiver operating characteristics curves were computed using independent predictive factors.

RESULTS

Several discrepancies were observed between preoperative and postoperative values, including existence of ulcer, gross type, and histology (all McNemar p-values were <0.001). Multivariate analyses identified the following independent predictive factors for lymph node metastasis: postoperative values including age (p = 0.002), tumor size (p < 0.001), and tumor depth (p < 0.001); preoperative values including age (p = 0.017), existence of ulcer (p = 0.037), tumor size (p = 0.009), and prediction of the presence of lymph node metastasis in computed tomography scans (p = 0.002). These postoperative and preoperative independent predictive factors produced areas under the receiver operating characteristics curves of 0.824 and 0.660, respectively.

CONCLUSIONS

Surgeons need to be aware of limitations in preoperative predictions of the presence of lymph node metastasis for clinical stage early gastric cancer.

Risk Factors for Lymph Node Metastasis in Early Gastric Cancer with Signet Ring Cell Carcinoma

BACKGROUND

Gastrectomy was reported to be an excessive approach for early gastric cancer with signet ring cell carcinoma. This study was conducted to explore the feasibility of endoscopic submucosal dissection for early gastric with signet ring cell carcinoma.

METHODS

Data from 1067 patients who underwent gastrectomy for early gastric cancer were collected retrospectively. The association between the clinicopathological factors and the lymph node metastasis was analyzed by univariate and multivariate logistic regression analyses.

RESULTS

Lymph node metastasis was confirmed in 17.2 % (184/1067) of patients. Meanwhile, the incidence of lymph node metastasis with each histology type was 13.1 % (26/198), 9.8 % (34/347), and 23.8 % (124/522) for signet ring cell carcinoma, differentiated carcinomas, and undifferentiated carcinomas, respectively. Signet ring cell carcinoma occurs more in women and young patients, with a higher predominance for mucosa. Various factors-including sex, tumor size, depth of tumor, and lymphovascular invasion-were found to be associated with lymph node metastasis for signet ring cell carcinoma (P < 0.05). Multivariate analysis revealed that tumor size (7.489, 95 % CI 2.025-27.701) and lymphovascular invasion (18.434, 95 % CI 3.256-104.359) were independent risk factors for lymph node metastasis (P < 0.05). Further analysis reveals there was no positive lymph node in patients with signet ring cell carcinoma when tumor confined to mucosa, size ≤2 cm and without lymphovascular invasion and ulceration.

CONCLUSIONS

Given the low risk of lymph node involvement, we recommend that endoscopic submucosal dissection be safely applied for early gastric signet ring cell carcinoma when tumor confined to mucosa, size ≤2 cm, and without lymphovascular invasion and ulceration.

Screening of differential microRNA expression in gastric signet ring cell carcinoma and gastric adenocarcinoma and target gene prediction

Gastric signet ring cell carcinoma (GSRCC) is a unique pathological type of gastric carcinoma that is extremely invasive and has a poor prognosis after diagnosis. The expression of microRNAs has been closely linked to the carcinogenesis of gastric cancer and has been considered as a powerful prognostic marker. Distinctive expression of miRNAs in GSRCC was investigated in the present study. Samples of GSRCC were compared to that of intestinal gastric adenocarcinoma using Agilent microarray technique, and two differentially expressed miRNAs were identified, hsa-miR-665 and hsa-miR‑95. qRT-PCR verification showed downregulation of both miRNAs in signet ring cell carcinoma and upregulation in gastric adenocarcinoma, which was not consistent with the results obtained by the microarray. Target gene prediction using online databases conferred two strong candidate genes, GLI2 and PLCG1. GO/KO analysis of these two genes showed close correlations with carcinogenesis and chemoresistance. It was concluded that hsa-miR-665 and hsa-miR-95 were downregulated in GSRCC but upregulated in intestinal gastric adenocarcinoma, and the relatively differential expression of the miRNAs negatively controlling their target genes could be closely related to the high invasive metastasis and chemoresistance of GSRCC.