Undifferentiated-type Gastric Carcinoma Research Articles

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 microvascular density in early gastric carcinoma using magnifying endoscopy with narrow-band imaging.

Background and study aims: Intramucosal vascular density differs between differentiated and undifferentiated type gastric carcinomas. This study aimed to evaluate the microvascular density characteristics of these two types of carcinoma using magnifying endoscopy with narrow-band imaging (ME-NBI). Patients and methods: In total, 42 differentiated and 10 undifferentiated types were evaluated. The microvessels observed using ME-NBI were extracted from stored still images and the microvascular density in the two carcinoma types was analyzed. Histological vascular density in resected specimens was also evaluated using CD34 immunostaining. Results: There were significant differences between the microvascular density in the differentiated and undifferentiated types of carcinoma (10.02 ± 4.72 % vs 4.02 ± 0.40 %; P < 0.001) using ME-NBI. Vascular density assessed histologically also differed significantly between differentiated and undifferentiated types in both the whole mucosal (5.81 ± 3.17 % vs 3.25 ± 1.21 %) and the superficial mucosal layers (0 – 100 μm) (6.38 ± 3.73 % vs 3.66 ± 1.46 %). However, the vascular density in the surrounding non-carcinomatous mucosa assessed using ME-NBI and histologically, was significantly lower in the differentiated than in the undifferentiated types (P < 0.001). There was good agreement between ME-NBI and histologically assessed microvascular density in both the whole (r = 0.740; P < 0.001) and superficial mucosal layers (r = 0.764; P < 0.001). White opaque substance (WOS) was seen in eight patients who had the differentiated type carcinoma. In almost all cases with WOS, the appearance of the carcinoma was discolored. Conclusions: There was a close relationship between ME-NBI assessed microvascular density and histologically assessed vascular density in the mucosal layer. Microvascular density differed significantly between the differentiated and undifferentiated types of carcinoma assessed using ME-NBI.

Genetic lineages of undifferentiated-type gastric carcinomas analysed by unsupervised clustering of genomic DNA microarray data

BackgroundIt is suspected that early gastric carcinoma (GC) is a dormant variant that rarely progresses to advanced GC. We demonstrated that the dormant and aggressive variants of tubular adenocarcinomas (TUBs) of the stomach are characterized by loss of MYC and gain of TP53 and gain of MYC and/or loss of TP53, respectively. The aim of this study is to determine whether this is also the case in undifferentiated-type GCs (UGCs) of different genetic lineages: one with a layered structure (LS+), derived from early signet ring cell carcinomas (SIGs), and the other, mostly poorly differentiated adenocarcinomas, without LS but with a minor tubular component (TC), dedifferentiated from TUBs (LS−/TC+).MethodsUsing 29 surgically resected stomachs with 9 intramucosal and 20 invasive UGCs (11 LS+ and 9 LS−/TC+), 63 genomic DNA samples of mucosal and invasive parts and corresponding reference DNAs were prepared from formalin-fixed, paraffin-embedded tissues with laser microdissection, and were subjected to array-based comparative genomic hybridization (aCGH), using 60K microarrays, and subsequent unsupervised, hierarchical clustering. Of 979 cancer-related genes assessed, we selected genes with mean copy numbers significantly different between the two major clusters.ResultsBased on similarity in genomic copy-number profile, the 63 samples were classified into two major clusters. Clusters A and B, which were rich in LS+ UGC and LS−/TC+ UGC, respectively, were discriminated on the basis of 40 genes. The aggressive pattern was more frequently detected in LS−/TC+ UGCs, (20/26; 77%), than in LS+UGCs (17/37; 46%; P = 0.0195), whereas no dormant pattern was detected in any of the UGC samples.ConclusionsIn contrast to TUBs, copy number alterations of MYC and TP53 exhibited an aggressive pattern in LS+ SIG at early and advanced stages, indicating that early LS+ UGCs inevitably progress to an advanced GC. Cluster B (enriched in LS−/TC+) exhibited more frequent gain of driver genes and a more frequent aggressive pattern than cluster A, suggesting potentially worse prognosis in UGCs of cluster B.

Clinicopathological characteristics and prognosis of signet ring cell carcinoma of the stomach

Signet ring cell carcinoma (SRC) of the stomach is a histological type based on microscopic characteristics. Although the distinctive clinicopathological features of SRC have been reported, results are inconsistent and survival outcomes are uncertain. We retrospectively studied 769 patients with gastric carcinoma who underwent gastrectomy in our institute from 1999 to 2009. Among them, 326 patients (42.4 %) had early gastric cancer (EGC) and 443 patients (57.6 %) had advanced gastric cancer (AGC). Sex, age, tumor location, macroscopic type, tumor size, microscopic invasion, and survival rate were compared between patients with SRC, differentiated-, and undifferentiated-type gastric carcinomas. Fifty-one patients (15.6 %) had SRC in EGC; there were significant differences in sex, age, location, macroscopic type, and size between SRC and the differentiated histological type. However, there was no difference between SRC and undifferentiated-type gastric carcinoma, except for the macroscopic type. Fifty-seven patients (12.9 %) had SRC in AGC. Sex, age, location, size, macroscopic type, perineural invasion, N stage, and hepatic metastasis were significantly different between SRC and the differentiated histological type. Undifferentiated-type gastric carcinoma differed in sex, macroscopic type, and hepatic metastasis. The overall survival rate differed between SRC and other cell types (P < 0.001). Among all the study patients, age [hazard ratio (HR) 1.013, P = 0.041] and tumor, node, and metastasis (TNM) stage (HR 2.350, P < 0.001) were important factors for predicting survival. Omitting patients with palliative resection or metastases, TNM stage was still an important factor for survival (HR 2.077, P < 0.001). Patients with SRC showed similar clinicopathological features with undifferentiated histology. The survival of patients with SRC reflected a better prognosis in patients with undifferentiated gastric carcinoma. However, when narrowing the patients to those with EGC only, survival in EGC patients exhibited no difference between histological types. Among AGC patients, SRC patients had a worse prognosis than other cell types.

MAGNIFYING ENDOSCOPIC FINDINGS OF THE SURFACE STRUCTURE OF NON‐CANCEROUS MUCOSA SURROUNDING DIFFERENTIATED AND UNDIFFERENTIATED GASTRIC CARCINOMA

Several reports have described the usefulness of magnifying endoscopy in observing the surface structure in gastric neoplasia. The aim of the present study was to evaluate the characteristics of the surface structure of non-cancerous mucosa surrounding gastric cancer. Sixty Japanese patients with early gastric cancer were enrolled in this study. We observed the non-cancerous gastric mucosa surrounding gastric carcinoma by magnifying endoscopy and classified the magnified view into four patterns: (A) dotted; (B) short-linear; (C) striped; and (D) granular, according to Sakaki's classification. All patients were diagnosed as having Helicobacter pylori infection, and histological evaluation revealed 46 types of differentiated and 14 types of undifferentiated-type gastric carcinomas. There were significant differences in the gender, age and endoscopic-atrophic-border scale between patients with these two types. In all, the surface structure at 240 points (4 points each in 60 patients) of non-cancerous mucosa was observed by magnifying endoscopy. The prevalences of the surface patterns of the mucosa surrounding differentiated carcinoma were: A, 1.1%; B, 8.1%; C, 28.3%; D, 62.5%, and those of the mucosa surrounding undifferentiated carcinoma were: A, 8.9%; B, 73.2%; C, 14.3%; D, 3.6%. There were significant differences in the surface structure of the non-cancerous mucosa surrounding differentiated and undifferentiated gastric carcinoma. The microsurface structure of the gastric mucosa surrounding gastric cancer lesions differed between patients with differentiated and undifferentiated gastric cancer. These findings are expected to be useful for the early detection of gastric carcinoma lesions or for the determination of extensions of carcinoma lesions.

Endoscopic resection of undifferentiated-type gastric carcinoma: an extreme step to be restrained?

Endoscopic mucosal resection (EMR) of gastric tumor was commenced in Japan in the 1970s to remove small superfi cial adenocarcinomas. Lymph node metastasis was the only limiting factor for EMR to be a curative treatment, and a number of studies were conducted using the surgical databases to specify gastric lesions that had never metastasized to the lymph nodes. All studies consistently showed that at least small differentiated (D-type) adenocarcinomas confi ned to the mucosal layer without ulceration were free from nodal metastasis.

Application of a novel method of double APAAP staining with subsequent quantitative image analysis to the examination of integrin expression in undifferentiated-type gastric carcinomas.

In undifferentiated-type gastric carcinoma (UGC), recognition of cancer cells is not easy, which has hampered its precise phenotypic analysis. To examine alterations of the integrin phenotype during the progression of UGC, we used double alkaline phosphatase anti-alkaline phosphatase staining and computer-aided image analyses for the expression of alpha1, alpha2, alpha3, alpha5, alpha6, alphaV, beta1, and beta4 integrin subunits and alphaVbeta3, alphaVbeta5, and alphaVbeta6 integrins in cytokeratin-positive cells in the mucosal, the submucosal, and the deeper parts of 10 early and 17 advanced UGCs, their non-neoplastic counterparts, and 9 lymph node (LN) metastases. We revealed declining expression of epithelial integrin subunits (alpha2, alpha3, alpha6, beta4) and increasing expression of mesenchymal integrin subunits (alpha1, alpha5) as the tumor invaded deeper, reflecting gradual epithelial-to-mesenchymal transition of the integrin phenotype during tumor invasion. Enhanced expression of the alphaV integrin subunit and alphaVbeta3 and alphaVbeta5 integrins correlated with tumor invasion, and that of alphaVbeta6 integrins with LN metastasis. Our results have demonstrated that the method we introduced is suitable for analysis of dynamic alterations of the integrin repertoire in UGC progression.

Intratumoural heterogeneity of intestinal expression reflects environmental induction and progression‐related loss of induction in undifferentiated‐type gastric carcinomas

Gene expression in tumours is regulated by environmental as well as genetic/epigenetic factors. This study assessed the environmental factors in intestinal expression of gastric cancers. We immunohistochemically examined intratumoural heterogeneity in the expression of Cdx2, MUC2, MUC5AC and MUC6 in 39 intramucosal and 49 extramucosally invasive undifferentiated-type gastric carcinomas (UGCs), consisting of signet ring cell carcinomas showing a layered structure (LS) in the mucosa and dedifferentiated tubular adenocarcinomas without LS and with minor tubular components (TC). The LS retains mucosal vertical polarity with superficial MUC5AC expression. Loss of this polarity was independent of intestinal expression and associated with extramucosal invasion. In LS(+) UGCs, intestinal expression was enhanced as the size of mucosal spread increased and was significantly reduced with deeper extramucosal invasion, whereas, in LS(-)/TC(+) UGCs, intestinal expression was frequent and predominant in the mucosa and was insignificantly reduced with deeper extramucosal invasion. In LS(+) UGCs, intestinal expression showed dynamic alteration probably by environmental induction and progression-related loss of induction, whereas it was relatively stable in LS(-)/TC(+) UGCs. Thus, intestinal expression in UGCs is not useful as a marker of tumour progression because it is also affected by environmental factors and genetic lineage.

Lineage analysis of undifferentiated-type gastric carcinomas dedifferentiated from tubular adenocarcinoma

Lineage analysis of undifferentiated-type gastric carcinomas dedifferentiated from tubular adenocarcinoma

How Wild-Type TP53 Is Inactivated in Undifferentiated-Type Gastric Carcinomas: Analyses of Intratumoral Heterogeneity in Deletion and Mutation of TP53

Objective: In undifferentiated-type gastric carcinoma (UGC), inactivation of TP53 is infrequent at early stages and comparable to tubular adenocarcinomas (TUBs) at advanced stages. To clarify how TP53 inactivation relates to histogenesis of UGCs, we examined p53 alterations in multiple samples of individual UGCs. Methods: We used 27 UGCs including 12 mixed types with minor tubular component (TC) and 16 with a layered structure (LS), a histological remnant of incipient signet ring cell carcinoma (SIG). We examined p53 expression immunohistochemically and analyzed loss of heterozygosity (LOH) with four microsatellite markers within 17p13.1 in multiple microdissected samples. DNA sequence of mutation hot spots in TP53 was determined in representative samples of each tumor. Results: In the mixed-type UGCs, 5 and 1 of the 8 tumors without LS showed global and regional loss of wild-type TP53, respectively, through mutation and LOH, and one fourth of the tumors with LS showed the regional loss. In the tumors with the mutation, the mutation pattern was identical between TC and poorly differentiated major component. Conclusion: The inactivation of wild-type TP53 is an earlier event before dedifferentiation of TUB to mixed-type UGC, but is less frequent and a later event in a subset of mixed-type UGC deriving from SIG.

Relationship between biological behavior and phenotypic expression in undifferentiated-type gastric carcinomas

It has been proved that some differentiated-type gastric carcinomas have a gastric phenotype. Similarly, it can be conjectured that some undifferentiated-type gastric carcinomas have an intestinal phenotype and that there are biological differences between undifferentiated-type gastric carcinomas with a gastric phenotype and those with an intestinal phenotype. We classified the phenotypes of early undifferentiated-type gastric carcinomas and investigated the relationship between their biological behavior and the phenotypes. Sixty lesions of intramucosal undifferentiated-type gastric carcinoma were classified into four phenotypes; gastric type, incomplete-intestinal type, complete-intestinal type, and unclassified type, according to the expression of CD10, MUC2, small-intestinal mucinous antigen (SIMA), human gastric mucin (HGM), or concanavalin A (ConA). The incidence of gastric-type carcinoma, incomplete-intestinal-type carcinoma, and complete-intestinal-type carcinoma was 33% (20 cases), 65% (39 cases), and 2% (1 case), respectively. There was no significant difference in any of the clinicopathological factors examined between the 20 gastric-type carcinomas and the 40 intestinal-type carcinomas, but there were significant differences in the morphological findings. Intestinal-type carcinomas had a glandular structure more frequently than the gastric-type carcinomas. The spreading pattern of gastric-type carcinomas showed a middle-layer type more frequently than the intestinal-type carcinomas. Undifferentiated-type gastric carcinomas frequently expressed an intestinal phenotype. There were differences in the growth patterns between undifferentiated-type gastric carcinomas with a gastric phenotype and those with the intestinal phenotype.

Expression of Tumor Suppressor and Tumor-related Proteins in Differentiated Carcinoma, Undifferentiated Carcinoma with Tubular Component and Pure Undifferentiated Carcinoma of the Stomach

The recent development of tissue microarray (TMA) technology allows high-throughput protein expression profiling of cancer tissues by immunohistochemistry. We attempted to clarify the derivation of undifferentiated-type gastric carcinoma with tubular component by using TMA. We constructed a TMA system composed of six paraffin blocks in which 274 samples of formalin-fixed gastric carcinoma tissue from 274 patients were embedded. Using this system, we performed immunohistochemical stains for five tumor suppressor and tumor-related proteins, i.e. p53, p16, hMLH1, c-erbB-2 and carcinoembryonic antigen (CEA). The 274 gastric carcinomas were histopathologically divided into the following three groups according to the degree of differentiation: differentiated-type (D-type), undifferentiated-type with tubular component (UT-type) and pure undifferentiated-type (UP-type). Immunohistochemical results were then compared with histological types. The percentages of abnormal expression of each protein in D-type, UT-type and UP-type carcinomas were as follows: 27% (38/143), 17% (17/98) and 15% (5/33) for p53; 27% (39/143), 19% (19/98) and 18% (6/33) for p16; 38% (54/143), 44% (43/98) and 24% (8/33) for hMLH1; 15% (22/143), 5% (5/98) and 0% (0/33) for c-erbB-2; and 22% (31/143), 35% (34/98) and 70% (23/33) for CEA. UP-type carcinomas exhibited the lowest frequencies of abnormal expression for p53, p16, hMLH1 and c-erbB-2, but the highest frequencies for CEA. UT-type carcinomas generally showed intermediate frequencies between those of D-type and UP-type carcinomas. Differences between D-type and UP-type for c-erbB-2 (P < 0.05) and CEA (P < 0.001) were significant, as were differences between D-type and UT-type for c-erbB-2 (P < 0.05) and CEA (P < 0.05), and differences between UT-type and UP-type for hMLH1 (P < 0.05) and CEA (P < 0.001). These findings reveal that gastric carcinomas have distinct expression profiles for tumor suppressor and tumor-related proteins depending on histological types, and support the hypothesis that UT-type carcinomas are derived not only from D-type but also from UP-type carcinomas. We also found significant differences between abnormal protein expression and other clinicopathological parameters such as gender, age and status of tumor and nodes.

Dynamic alteration of the E‐cadherin/catenin complex during cell differentiation and invasion of undifferentiated‐type gastric carcinomas

To examine qualitative alterations of the E-cadherin/catenin complex (CCC) during cell differentiation and invasion of undifferentiated-type gastric carcinoma, immunoreactivity for the intracytoplasmic domain and the extracellular domain (ECD) of E-cadherin, and that of beta-catenin, was analysed in the mucosal, submucosal, and deepest invasive parts of 20 early and 20 advanced cancers that had a component of intramucosal signet ring cell carcinoma. Histological subtype affected the mode of E-CCC alteration. The tumours with a tubular component and without organized differentiation of signet ring cells in a layered structure were associated with nuclear expression of beta-catenin and may derive from tubular adenocarcinomas through de-differentiation and de-regulation of the Wnt pathway. These tumours were characterized by relatively stable ECD expression throughout the course of tumour progression. On the other hand, the tumours with a layered structure, which may derive from signet ring cell carcinoma by de novo abnormality of E-cadherin, were characterized by dynamic alteration of ECD expression during cell differentiation and tumour progression; intramucosal spread (with a layered structure) as well as deep invasion (beyond the submucosa) commonly showed cellular dissociation with downregulation of ECD, whereas submucosal invasion and lymph node metastasis often showed cellular cohesion and retention (or 'reappearance') of ECD. Thus, cellular dissociation did not always reflect enhanced invasive activity but may be reversibly regulated during tumour progression.

Lineage Analyses of Undifferentiated-type Gastric Carcinomas

Lineage Analyses of Undifferentiated-type Gastric Carcinomas

Molecular Characterization of Undifferentiated-Type Gastric Carcinoma

As the great majority of gastric cancers develop histologically differentiated, and a significant proportion of differentiated-type carcinomas progress to become undifferentiated, both histological types are likely to share several common genetic abnormalities, such as p53 mutations at advanced stages. However, a subset of gastric cancers develop as undifferentiated carcinomas, including signet-ring cell carcinoma and poorly differentiated adenocarcinoma, and the molecular pathogenesis of this tumor type remains largely unknown. To characterize the molecular features of undifferentiated-type gastric carcinomas that developed as undifferentiated-type, we examined for p53, APC, and epithelial (E)-cadherin gene mutations, microsatellite alterations including loss of heterozygosity (LOH) and microsatellite instability (MSI), and hypermethylation of the E-cadherin gene promoter in 26 early undifferentiated gastric carcinomas, consisting of 14 signet-ring cell carcinomas and 12 poorly differentiated adenocarcinomas. E-cadherin expression was evaluated immunohistochemically. p53 mutations were detected in only one poorly differentiated adenocarcinoma sample (3.8%; 1/26), whereas no APC or E-cadherin mutations were found. LOH was present only at D8S261 on the short arm of chromosome 8 in 2 of 14 (14%) informative tumors, both of which were poorly differentiated adenocarcinomas, and MSI was not observed in any of the tumors. No signet-ring cell carcinomas have been found to carry gene mutations or microsatellite alterations. In contrast, hypermethylation of the E-cadherin promoter occurred in 69% (18/26) of the tumors; 57% (8/14) of signet-ring cell carcinomas, and 83% (10/12) of poorly differentiated adenocarcinomas, and was significantly associated with loss or reduced expression of E-cadherin. Thus, whereas tumor suppressor gene mutation, LOH, and MSI were less common in undifferentiated-type early gastric carcinomas, epigenetic inactivation of E-cadherin via promoter hypermethylation may be an early critical event in the development of undifferentiated tumors.

Ultrastructural characterization of enterochromaffin-type cells in human gastric carcinoma.

Ultrastructural characterization has been performed on eosinophilic granular cells occurring in gastric carcinomas. Of these, the present paper dealt with enterochromaffin (EC)-type cells. EC-type cells were identified by the presence of eosinophilic granules, immunoreactivity for serotonin (5 HT) and argentaffinity. Conventional electron microscopy revealed that they bore membrane bound, electron-dense granules of varying size (100-800 nm in shorter diameter), which were larger than those of normal EC cells. Their shapes are round, rod-shaped and concave. The granules are immunolabeled for 5HT by both pre- and post-embedding methods. The preembedding method also disclosed diffuse cytosolic immunoreactivity. Both differentiated-type and undifferentiated-type gastric carcinomas showed essentially the same results. General trends of occurrence of Paneth-like and EC-type cells in gastric carcinomas were also discussed. The present study confirmed that EC-type cells in gastric carcinoma retained basic characteristics of EC cells despite of morphological deviation from the normal cells. It is speculated that they are derived from neoplastic precursor cells with a special differentiation.

Ultrastructural immunolocalization of lysozyme in paneth-like cells in undifferentiated (gastric)-type carcinoma of the stomach.

Five cases of gastric carcinoma of undifferentiated (gastric) type containing Paneth-like cells were studied by immunoelectron microscopy for lysozyme using two methods. The Paneth-like cells in these carcinomas had lost their cellular polarity and possessed electron-dense granules. These granules varied in size (0.5-3 micron in diameter), electron density and shape. Post-embedding method revealed immunolocalization of lysozyme in these granules in all cases, similar to that in normal Paneth cells. Pre-embedding method showed immunoreactivity diffusely or focally located in the cytoplasm, but this approach was unable to reveal immunoreactivity in the granules, a feature also common to normal cells. Our study therefore confirmed that Paneth-like carcinoma cells and normal Paneth cells had the same features, and indicated that undifferentiated-type gastric carcinoma could possess specially differentiated cells, providing further support that such carcinoma could express multipotentiality. The difference in the results obtained by the two immunoelectron microscopy methods was discussed.