Multiple simultaneous gastric carcinomas

The correlation between the main and minor lesions of synchronous multiple gastric neoplasms assessed gastroscopically and microscopically

BACKGROUND

Patients with early gastric cancer (EGC) are at high risk of developing synchronous multiple gastric neoplasms (SMGNs) after undergoing endoscopic submucosal dissection (ESD). However, most previous studies have had small sample sizes, and few have focused on association studies.

AIMS

This study aimed to analyze the associations between SMGN lesion data from patients with EGC treated with ESD and their correlation coefficients.

METHODS

The clinical ESD data from two hospitals from January 2008 to January 2021 were retrospectively analyzed. The main lesions were defined as those with a significant depth of infiltration. The larger tumor diameter was considered the main lesion if the lesions had the same infiltration depth.

RESULTS

Of the 1013 post-ESD cases examined, 95 cases (223 lesions) had SMGN, and 25 patients had more than three lesions. For the correlation analysis, 190 lesions were included. The study revealed a similarity in pathological type between main and minor lesions (rs = 0.37) and a positive correlation in infiltration depth (rs = 0.58). The mean diameter sizes of the main and minor lesions were 20.7 ± 8.3 mm and 13.1 ± 6.4 mm, respectively, with statistically significant differences (P < 0.001). A linear correlation was observed between the diameter size and a linear regression model was constructed, producing r = 0.38 [95% confidence interval (CI) 0.19-0.54], b = 0.29 (95% CI 0.14-0.44), t = 3.94, P < 0.001]. A correlation was identified between the vertical distribution of the main and minor lesions, the horizontal distribution, and the gross endoscopic morphology (ϕc = 0.25, P = 0.02; ϕc = 0.32, P < 0.001; ϕc = 0.60, P < 0.001).

CONCLUSIONS

The correlation coefficients for microscopic characteristics were higher than those for gastroscopy. There is a significant positive correlation between the main and minor lesions regarding pathological stage and depth of infiltration, respectively. The spatial distribution of the lesions and the gastroscopic morphology were similar.

Intestinal metaplasia and anastomotic recurrence of gastric carcinoma

Intestinal metaplasia (IM) of the stomach has been shown to increase the relative risk of gastric cancer. Endoscopic surveillance has been proposed and advocated for populations at risk. Those patients who had undergone surgery for gastric malignancy exhibited precancerous lesions such as atrophic gastritis and IM, and the possibility of anastomotic recurrence is higher than for the patients who had undergone benign gastric surgery. At present, there are no other recognized good markers of gastric dysplasia or cancer. We reviewed the literature on IM of the stomach to ascertain whether residual premalignant (type III) IM may predispose to anastomotic recurrence of gastric cancer.

Genetic and epigenetic markers to identify high risk patients for multiple early gastric cancers after treatment with endoscopic mucosal resection

The development of multiple gastric cancer is a major problem after the endoscopic resection of the first early gastric cancer. To find out markers to identify high risk patients, we analyzed the microsatellite instability (MSI) status and hypermethylation of tumor-related genes in multiple gastric cancers. Sixty-four adenocarcinomas resected by endoscopy, including 32 early solitary gastric cancers (SGCs) from 32 patients and 32 multiple gastric cancers (MGCs) from 14 patients, were employed. We analyzed MSI and the methylation status of promoter regions of the hMLH1, MGMT, p16 and E-cadherin using methylation-specific Polymerase Chain Reaction. Expression levels of hMLH1 were examined by immunohistochemistry. MSI (+) was detected in 5 of the 14 (35.7%) patients with MGCs, and in only 3 of the 32 patients (9.3%) with SGCs. Significant differences were observed between the 2 groups (p<0.001). Hypermethylation of hMLH1 was more frequently detected in MGCs than in SGCs (p<0.01), whereas significant difference was not observed in the frequency of MGMT, p16 or E-cadherin promoter methylation between the 2 groups. In conclusion, our results indicate that inactivation of hMLH1 through promoter hypermethylation may be involved in the development of multiple gastric cancers following the MSI pathway.

Expression of p53, c-erbB-2 and Ki67 in intestinal metaplasia and gastric carcinoma

AIM: To compare two types of classification of intestinal metaplasia (IM) of the stomach and to explore their relationship to gastric carcinoma.

METHODS: Forty-seven cases of gastric IM were classified into type I, type II or type III according to mucin histochemical staining and compared with a novel classification in which the specimens were classified into simple IM (SIM) or atypical IM according to polymorphism in terms of atypical changes of the metaplastic epithelium. Forty-seven IM and thirty-seven gastric carcinoma samples were stained for p53, c-erbB-2 and Ki67 proteins by Envision immunohistochemical technique.

RESULTS: There were no significant differences in the expression of p53 and c-erbB-2 among type I, type II, type III IM and gastric carcinomas. The positive expression rate of Ki67 was significantly higher in gastric carcinomas than in type I IM while no significant Ki67 expression differences were observed among type II, type III IM and gastric carcinomas. The expression of p53, c-erbB-2 and Ki67 proteins in 20 SIM, 27 Atypical IM and 37 gastric carcinomas showed significant differences between SIM and gastric carcinomas while no significant differences were observed between Atypical IM and gastric carcinomas.

CONCLUSION: Atypical IM may better reveal the precancerous nature of IM and could be a helpful indicator in the clinical follow up of patients.

Endoscopic Screening for Remnant Gastric Cancer: Points to be Considered

BACKGROUND/AIMS

It is difficult to detect early gastric cancer (EGC) during endoscopic surveillance because the remnant stomach is usually deformed after surgical resection and the mucosa at the gastric stump are changed due to bile reflux. In this study, we aimed to determine the characteristic endoscopic findings of cancer in the remnant stomach.

METHODS

Fifty-five remnant gastric cancer (RGC) patients were classified into three groups according to location and elapsed time after surgery. Among 32 RGCs that developed less than 10 years after surgery, 21 lesions were located close to the anastomosis site (recurrent cancers), whereas 11 lesions were not (residual cancers). Twenty-three cancers developed at least 10 years after surgery (newly developed cancers). The endoscopic features were compared among these groups.

RESULTS

Most patients (29/32, 91%) with residual or recurrent cancer developed their tumors within five years after surgery, and the proportion of EGC was 43.8% (14/32). However, 91.3% (21/23) of newly developed cancers were advanced gastric cancers. When classified according to the Japanese classification system for EGC, 71% (5/7) of the residual cancers were of the elevated type, whereas 86% (6/7) of the recurrent cancers were of the depressed type (p=0.00).

CONCLUSIONS

During the first 5 years after subtotal gastrectomy, endoscopists should mainly try to find depressed lesions on the anastomosis site as well as elevated lesions on the non-anastomosis site.

Clinicopathologic and immunohistochemistry characterization of synchronous multiple primary gastric adenocarcinoma

The aim of this investigation was to evaluate clinicopathologic and immunohistochemical characteristics of synchronous primary gastric adenocarcinomas. Immunohistochemistry for p53 (suppressor pathway) and for hMLH1, hMSH2, and hMSH6 (mutator pathway) was performed using ABC-technique amplification by biotinylated tyramide. Synchronous primary gastric adenocarcinomas were detected in 19/553 (3.43%) of the patients. The tumors were localized in distal stomach in 22, body in 14, and proximal in five. There was a predominance of intestinal type in the group of synchronic tumors compared to the solitary lesions, 73.2 vs 37.3%, p = 0.001. Synchronous neoplasias were diagnosed in earlier stage than solitary neoplasias, T1-T2 = 60.9% vs T1-T2 = 28.4%, p = 0.0001; and N0 = 68.4% vs N0 = 26.2%, p = 0.001. p53 was detected in 52.6% of the patients with synchronous tumors. Altered hMLH1 immunoexpression occurred in 26.3% of the patients and hMSH6 in 5.3%. hMSH2 immunoreactivity was positive in all tumors. p53 was solely detected in 17 tumors, while hMLH1 was altered in 10/24 negative p53 tumors, p = 0.01. Synchronous gastric adenocarcinomas presented higher frequency of intestinal type and early gastric cancer in comparison to solitary gastric cancer. Two routes of carcinogenesis, mutator, and suppressor appear to be involved independently in the development of synchronous tumors.

Microsatellite analysis of synchronous and metachronous tumors: a tool for double primary tumor and metastasis assessment

Despite well-established histopathological features and the development of immunostaining of human neoplasms, there are a number of cases in which surgical pathologists cannot assure the origin of synchronous and metachronous tumors. In many cases, the classification of these lesions as either two separate primary tumors or as a single primary tumor with a metastasis has significant implications with respect to patient prognosis and recommendations for therapy. To establish the origin of tumors, we assessed tumor cell clonality using PCR-based microsatellite analysis on microdissected archival tissues for loss of heterozygosity (LOH) and microsatellite instability (MSI) in a series of 19 paired synchronous and metachronous tumors from several organs. As a control group, 15 autopsy cases with an unequivocally recognizable primary tumor and associated metastases were also examined. Based on LOH and MSI findings, and using a panel of 4 to 12 (median 7) microsatellite markers, we were able to establish the clonal pattern of microsatellite changes in 17 out of 19 (89%) biopsy cases and thus determine if they were either double primary tumors (41%) or metastases (59%). Of interest, identical or similar pattern of microsatellite abnormalities were detected in 15 primary tumors and corresponding metastasis from autopsies. Our results indicate that microsatellite analysis for LOH and MSI, as an expression of clonality, provides a useful tool to distinguish double primary neoplasms and metastases in synchronous and metachronous tumors.

Mucin phenotype and microsatellite instability in early multiple gastric cancers

Clinicopathologically, multiple gastric cancers (MGCs) are reported to involve predominantly intestinal-type adenocarcinoma and frequently to be associated with severe intestinal metaplasia. However, there are few reports concerning the characteristic biomarkers of early MGCs. The aim of our study was to identify the cellular lineage defined by mucin phenotypes and the relationships among mucin phenotypes, background mucosa and microsatellite instability (MSI) of early MGCs. We examined mucin phenotypes of 63 surgically resected carcinomas from 25 patients with early MGCs and 39 early solitary gastric cancers (SGCs) by immunohistochemical analysis using a panel of monoclonal antibodies. MSI and the degree of intestinal metaplasia (IM) on the background mucosa were also examined. In early MGCs, the incidence of cancer exhibiting the gastric phenotype (G-type) was 59% (37 of 63 cancers), which was higher than that in early SGCs (23%, 9 of 39 cancers). There was a significant difference between the distributions of mucin phenotypes in early MGCs and early SGCs (p = 0.001). Whereas half of the G-type cancers in early MGCs were related to severe IM, none of the G-type cancers in early SGCs were related to severe IM. In the early MGCs, MSI was observed in 21 of 63 cancers (33.3%). In contrast, MSI was observed in only 3 of the 39 (7.7%) early SGCs, indicating a significant difference between these 2 groups (p < 0.01). Our results suggest that the characteristic features of early MGCs are the gastric mucin dominant phenotype and high frequency of MSI.

Microsatellite instability in synchronous gastric carcinomas

Synchronous gastric carcinomas are found in 4% to 10% of all gastric carcinomas, and the tumor multiplicity is believed to be related to genetic predisposition. To investigate the role of mismatch repair error in synchronous gastric carcinomas, we analyzed the microsatellite instability (MSI) status of 101 cancers from 48 gastrectomy specimens and compared them with 149 solitary gastric carcinomas. Multiple synchronous gastric carcinomas are characterized by slightly older age, predominance in males, early stage and lower lymph node metastasis. Among the 48 cases, 8 (18 lesions) were associated with a gastric adenoma (type I) and 40 (83 lesions) were not associated with a gastric adenoma (type II). The MSI+ rate was 50% in the type I and 8.4% in the type II synchronous gastric carcinomas (p < 0.001), while that of solitary gastric carcinomas was 9.4%. In addition, the frameshift mutation rates of the TGF-betaRII, BAX and hMSH3 genes in the type I synchronous carcinomas were higher than those in the type II synchronous carcinomas. These findings indicate that a defect in the mismatch repair system might play a role in the carcinogenesis of a minor subset of multiple gastric carcinomas associated with adenomas.