Immunohistochemically detectable Cdx2 is present in intestinal phenotypic elements in early gastric cancers of both differentiated and undifferentiated types, with no correlation to non-neoplastic surrounding mucosa

The Different Clinicopathological Features of Remnant Gastric Cancer Depending on Initial Disease of Partial Gastrectomy

Background: The incidence of gastric cancer increases in the remnant stomach after partial gastrectomy; however, its pathogenesis remains controversial. The clinicopathological features and immunohistochemical subtype were evaluated in patients with remnant gastric cancer considering the initial cause of partial gastrectomy. Methods: We categorized 59 cases of remnant gastric cancer who underwent curative surgery between 2001 and 2016 according to initial pathologies of benign (n = 24) or malignant (n = 35). Histological changes including pyloric metaplasia and intestinal metaplasia in the mucosa around the anastomosis site and the background mucosa of carcinomas were compared between the groups. Results: In the malignant group, the proportion of male patients was substantially lower, with a shorter interval. In background mucosa around the carcinomas, incidence of high-grade pyloric metaplasia was significantly higher in the benign group (13/20, 65.0% vs. 10/28, 35.7%), while high-grade intestinal metaplasia was only observed in the malignant group (0/20, 0% vs. 7/28, 25.0%). Conclusions: The cancers in the initial benign disease are mainly associated with pyloric metaplasia at the anastomosis site, reflecting reflux, but not with intestinal metaplasia. On the other hand, in the initial malignant disease group, intestinal metaplasia has an equally important role as reflux-associated pyloric metaplasia.

Green epithelium revealed by narrow-band imaging (NBI): a feature for practical assessment of extent of gastric cancer after H. pylori eradication

Background and study aims Assessment of the extent of gastric cancer detected by endoscopy after successful eradication of H. pylori is often difficult even with narrow-band imaging (NBI)-magnifying endoscopy. Using the latter modality, it has often been noted that the cancerous area has a brownish color surrounded by green epithelium (GE). If the histological origin of this GE could be clarified, it could be of practical use for endoscopic assessment of the extent of cancer.

Materials and methods The endoscopic appearance of gastric cancer after eradication therapy was classified into four types: (A) cancer brownish, surrounding mucosa green; (B) cancer brownish, surrounding mucosa brownish; (C) cancer green, surrounding mucosa brownish; and (D) cancer green, surrounding mucosa green. A histological series of sections taken from tissues in each endoscopic view was stained with HE, and also for CDX2, MUC2, CD10 and MUC5AC. Staining intensity was evaluated by microscopy using a visual analog scale ranging from 0 to 3+: intensities of 0 and 1+ were rated as negative, and those of 2+ and 3+ as positive. Positive or negative immunostaining was examined for each type of endoscopic appearance A – D.

Results Among 42 lesions examined, 16 were type A, 18 type B, 6 type C and 2 type D. MUC2 was positive in the surrounding mucosa in 100 % of type A and D cases, but in only 28 % and 17 % of type B and C cases, respectively.

Conclusions GE observed by NBI-endoscopy corresponds to MUC2-positive mucosa and is thought to be a feature for practical assessment of the extent of cancer.

Re-evaluation of Phenotypic Expression in Differentiated-type Early Adenocarcinoma of the Stomach

A total of 313 cases of differentiated-type early gastric adenocarcinomas, including 113 cases of small-sized carcinoma (5< × ≤10 mm) and 121 cases of microcarcinoma (0< × ≤5 mm), were examined immunohistochemically to clarify the phenotypic expressions. They were classified into four categories (gastric phenotype (G-type), intestinal phenotype, gastrointestinal phenotype, and null phenotype) by a two-step process: the phenotype based on an immunoprofile of mucin core proteins (MUCs) with CDX2 (w/.CDX2-assessment); and the phenotype of MUCs only (w/o.CDX2-assessment). CDX2 expression was observed in 89.1% (279/313); it was highly expressed in 87.6% (106/121) of microcarcinomas. MUC2 expression increased as tumor size increased (P < 0.05). Compared with w/o.CDX2-assessment, w/.CDX2-assessment showed significantly fewer G-type carcinomas (P < 0.05). Each phenotype marker was less expressed in the submucosal part than in the mucosal part. In conclusion, CDX2 was a sensitive marker for assessing intestinal phenotype. A large portion of the early differentiated-type adenocarcinomas expressed CDX2 from the very early stage of carcinogenesis, and the proportion of G-type was unexpectedly low. Lower expression of each phenotype marker was considered the cause of phenotype alteration during submucosal invasion.

Intestinal metaplasia in Barrett's oesophagus may be an epiphenomenon rather than a preneoplastic condition, and CDX2-positive cardiac-type epithelium is associated with minute Barrett's tumour

AIMS

Although intestinal-type epithelium in Barrett's oesophagus has been traditionally recognized as having a distinct malignant potential, whether this also holds true for cardiac-type epithelium remains controversial. The aim of this study was to identify a type of epithelium that is highly associated with Barrett's tumour.

METHODS AND RESULTS

We analysed tumours and the corresponding background mucosa with special regard to tumour size in 40 cases of superficial Barrett's tumour by using immunohistochemical staining for CDX2, CD10, MUC2, MUC5AC, and MUC6. Intestinal metaplasia in tumour-adjacent mucosa was not associated with tumour size, but was significantly correlated with the extent of Barrett's oesophagus (P < 0.001). The majority (69.2%, 9/13) of small tumours (≤10 mm) had no intestinal metaplasia in adjacent non-neoplastic mucosae. Minute (≤5 mm) tumours were significantly associated with a gastric immunophenotype (P < 0.001). Purely gastric-immunophenotype tumour cells expressed CDX2, and cardiac-type epithelium adjacent to small tumours also showed low-level CDX2 expression.

CONCLUSIONS

Our data suggest that intestinal metaplasia in Barrett's oesophagus is an epiphenomenon rather than a preneoplastic condition, and that CDX2-positive cardiac-type epithelium is highly associated with minute Barrett's tumour. Further prospective studies are needed to evaluate the risk of malignancy of cardiac-type epithelium with regard to sub-morphological intestinalization.

"Crawling-type" adenocarcinoma of the stomach: a distinct entity preceding poorly differentiated adenocarcinoma

BACKGROUND

Gastric "crawling-type" adenocarcinoma (CTAC) is a neoplasm histologically comprising irregularly fused glands with low-grade cellular atypia that tends to spread laterally in the mucosa. It is necessary to elucidate the clinicopathological characteristics of CTAC.

METHODS

We evaluated 25 CTACs-16 intramucosal (M-) and 9 submucosal invasive (SM-) cancers-clinicopathologically and immunohistochemically.

RESULTS

CTAC was most frequently located in the lesser curvature of the middle-third of the stomach. Macroscopically, 21 lesions were superficial-depressed and 4 were superficial-flat type. Histologically, all CTACs had cystic dilated glands and 16 lesions had focal signet-ring cells. All invasive areas of the SM-CTACs were occupied by poorly differentiated adenocarcinoma with an infiltrative growth pattern and abundant stroma. Fifteen CTACs were surrounded by mucosa with partial or no intestinal metaplasia. In the intramucosal area, 24 lesions were mixed phenotype with mucin and brush border immunoexpression. SM-CTAC was frequent in lesions with an intramucosal poorly differentiated component (PDC) greater than 10 mm in size (P = 0.041), and lymph node metastasis (LNM) was frequent in lesions with a PDC greater than 20 mm (P = 0.039). The frequency of an expanded pattern (Ki-67-positive cells occupying > 50 % of the mucosa) was higher in SM-CTAC than in M-CTAC (P = 0.027). p53 overexpression was not detected in the intramucosal areas of any of the lesions.

CONCLUSION

CTAC is a distinct subgroup of gastric adenocarcinoma in the early phase. A larger PDC and a Ki-67 expanded pattern were predictive of submucosal invasion or LNM.

Re-evaluation of phenotypic expression in undifferentiated-type early gastric adenocarcinomas using mucin core protein and CDX2

BACKGROUND

Undifferentiated-type early gastric adenocarcinomas are generally classified into two groups: pure undifferentiated-type adenocarcinomas, which naturally develop as undifferentiated-type without a glandular component; and mixed differentiated/undifferentiated-type adenocarcinomas, which are associated with some vestigial glandular component and presumably develop from differentiated-type adenocarcinoma. The differences in phenotypic expression between these two groups were examined using mucin core protein and CDX2.

METHODS

A total of 210 lesions of undifferentiated-type early gastric adenocarcinoma less than 25 mm in diameter were classified into four categories (gastric type, gastrointestinal type, intestinal type, and null type) based on their MUC5AC, MUC6, MUC2, and CDX2 immunoprofiles.

RESULTS

Gastric type was significantly (p < 0.01) decreased and gastrointestinal type was significantly (p < 0.01) increased both in pure undifferentiated-type adenocarcinomas and in mixed differentiated/undifferentiated-type adenocarcinomas when CDX2 was applied to mucin core protein. In the pure undifferentiated-type adenocarcinomas, gastric type decreased and gastrointestinal type increased as tumor size increased (p < 0.05). In contrast, in the mixed differentiated/undifferentiated-type adenocarcinomas, gastrointestinal type was most common even in small-sized (≤10 mm) carcinomas and was generally stable regardless of tumor size. In submucosal carcinomas, gastrointestinal type decreased and gastric type and intestinal type increased during carcinoma invasion from the intramucosal to submucosal parts (p < 0.05). The positivity rates for all phenotypic markers, especially gastric markers, tended to decrease during submucosal invasion.

CONCLUSIONS

CDX2 is a sensitive marker for assessing intestinal phenotypic expression, and it is likely that there are two different pathways of tumor progression in undifferentiated-type adenocarcinoma of the stomach, according to phenotypic expression.

Prognostic significance of Cdx2 immunohistochemical expression in gastric cancer: a meta-analysis of published literatures

Cdx2 is a homeobox domain-containing transcription factor that is important in the development and differentiation of the intestinal cells, and served as a potential biomarker of tumor progression in early intestinal-type gastric cancer. However, its prognostic value and significance in gastric cancer remain controversial. A meta-analysis based on published studies was performed to obtain an accurate evaluation of the association between the presence of Cdx2-positive in clinical samples and clinical outcome. A total of 13 eligible retrospective cohort studies with 1513 patients were included. Cdx2-positive cases were significantly associated with higher male-to-female ratio (RR=1.27, 95% CI: 1.17-1.38, P<0.00001 fixed-effect), lower (I+II) clinical stage (RR=1.63, 95% CI: 1.42-1.87, P<0.00001 fixed-effect), better histologic differentiation (RR=1.54, 95% CI: 1.34-1.76, P<0.00001 fixed-effect), and lower rate of vascular invasion (RR=1.23, 95% CI: 1.08-1.41, P=0.002 fixed-effect) and lymph node metastasis (RR=1.52, 95% CI: 1.33-1.73, P<0.00001 fixed-effect), as well as higher 5-year survival rate (HR=2.22, 95% CI: 1.78-2.75, P<0.00001 fixed-effect). However, the presence of Cdx2 was not associated with tumor size. In summary, Cdx2 is a prognostic factor in gastric cancer, which acts as a marker of good outcome in patients with gastric cancer. Further clinical studies are needed to confirm the role of Cdx2 in clinical practice.

Helicobacter pylori infection and gastric carcinogenesis in rodent models

Helicobacter pylori infection is an important factor for gastric carcinogenesis in human. In carcinogen-treated Mongolian gerbils, H. pylori infection enhances stomach carcinogenesis, while infection alone induced severe hyperplasia called heterotopic proliferative glands. A high-salt diet or early acquisition of the bacteria exacerbates inflammation and carcinogenesis. Oxygen radical scavengers or anti-inflammatory chemicals as well as eradication of H. pylori are effective to prevent carcinogenesis. H. pylori-associated inflammation induces intestinal metaplasia and intestinalization of stomach cancers independently. It is necessary to control cancer development not only in H. pylori-positive cases but also in H. pylori-negative metaplastic gastritis.

Relationship between alpha-methylacyl-coenzyme A racemase expression and mucin phenotype in gastric cancer

Alpha-methylacyl-coenzyme A racemase controls β-oxidation of branched-chain fatty acid and their derivatives. Many investigators have described alpha-methylacyl-coenzyme A racemase expression in various neoplasias and their precursor lesions. Although there have been a few reports regarding alpha-methylacyl-coenzyme A racemase expression in gastric neoplasia, these reports did not discuss the relationship between alpha-methylacyl-coenzyme A racemase expression and mucin phenotype. This study analyzed alpha-methylacyl-coenzyme A racemase expression of gastric carcinomas with regard to mucin phenotype. Alpha-methylacyl-coenzyme A racemase expression was evaluated in 85 cases of gastric biopsies including gastric epithelial neoplasia and nonneoplasia and in 108 cases of surgically resected early gastric cancer. In biopsy cases, alpha-methylacyl-coenzyme A racemase was more highly expressed in neoplasia (69.7%, 23/33) than in nonneoplasia (0%, 0/42) (P = .001). Alpha-methylacyl-coenzyme A racemase was overexpressed in 20.0% (2/10) of cases that were indefinite for neoplasia, and the 2 positive cases were ultimately diagnosed as adenocarcinoma. In resected cases of early gastric adenocarcinoma, alpha-methylacyl-coenzyme A racemase expression significantly correlated with mucin phenotype (P = .003), but not with tumor progression, histologic classification, or clinicopathologic features. Alpha-methylacyl-coenzyme A racemase expression was significantly higher in intestinal-phenotype carcinoma (90.2%, 37/40) than in gastric-phenotype carcinoma (56.3%, 18/31) (P = .006) and also correlated with an increase in CDX2 expression (P = .018) and a decrease in MUC5AC expression (P = .048). This tendency was observed in all histologic types. Our results indicate that alpha-methylacyl-coenzyme A racemase is a useful marker for distinguishing gastric neoplasia from nonneoplasia even at an early stage. Alpha-methylacyl-coenzyme A racemase expression is associated with mucin phenotypes of gastric neoplasia, particularly with the expression of CDX2 and MUC5AC.

Histopathological phenotypes of early gastric cancer and its background mucosa

Recent advances in endoscopic submucosal dissection (ESD) techniques contribute to endoscopic treatment of early gastric cancer (EGC). Recognition of chronic atrophic gastritis as the background is important for high-quality detection and diagnosis of EGC. But, relationships between EGC and atrophy of the background gastric mucosa caused by Helicobacter pylori are not well understood. The present study demonstrated histopathological phenotypes of EGC, as well as chronic atrophic gastritis as background mucosa of EGC. We evaluated mucosal heights, number of glands, and degree of intestinal metaplasia (IM) of the background gastric mucosa, using 81 cases of EGC resected by ESD. Gastric phenotype cancer cases showed IM of the background gastric mucosa less frequently, compared with intestinal phenotype cancer cases (score of IM, 1.15 vs. 1.65, P = 0.012). The average mucosal heights around EGC were lower in moderately to poorly differentiated adenocarcinoma cases than well differentiated adenocarcinoma cases (442.6 µm vs. 500.2 µm, P = 0.011). The mucosal atrophy indicated by average heights of background mucosa was low in the gastric phenotype cancer cases, compared with the intestinal phenotype cancercases (452.8 µm vs. 505.6 µm, P = 0.018). In the fundic gland area, the mucosal heights were low in the gastric phenotype cancer cases, compared with the intestinal phenotype cancer cases (413.2 µm vs. 495.5 µm, P = 0.015). Our results using EGC specimens indicated that gastric phenotype cancer and moderately to poorly differentiated adenocarcinoma had atrophic background mucosa with lower mucosal heights and less IM. The atrophic gastric mucosa with less IM is thought to play an important role in gastric carcinogenesis, especially tumoriogenesis of gastricphenotype cancer.

Endoscopic diagnosis of open-type atrophic gastritis is related to the histological diagnosis of intestinal metaplasia and Cdx2 expression

BACKGROUND AND OBJECTIVES

Long-term Helicobacter pylori infection results in atrophic gastritis and intestinal metaplasia (IM) with Cdx2 expression. We have tried to determine if there was a link between endoscopic and histological diagnosis of IM based on the status of aberrant Cdx2 expression.

METHODS

One hundred and one subjects agreed to upper gastrointestinal endoscopic examination, with biopsy sampling for histology, Giemsa, and Cdx2 immunohistochemical staining before and after the treatment. On endoscopic examination, atrophic gastritis was defined as discoloration with blood vessel transparency, and was classified as either closed or open. Metaplastic gastritis was defined by the presence of whitish patches, whitish plaques, and/or homogeneous whitish discoloration. Histologic analysis was performed to determine H. pylori density, intensity of acute polymorphonuclear cell infiltrates and chronic mononuclear infiltrates, gastric atrophy, and IM as demonstrated using immunohistochemistry for cdx2.

RESULTS

Cdx2 protein expression (P=0.018) and the prevalence of histologically detected IM (P=0.011) were higher in cases of endoscopically diagnosed open-type atrophic gastritis and metaplastic gastritis than in closed-type atrophic gastritis and nonatrophic/nonmetaplastic cases. The degree of activity (P=0.006) and inflammation (P=0.007) improved significantly after four weeks of successful H. pylori eradication treatment, whereas the degree of atrophy, metaplasia, and Cdx2 expression did not.

CONCLUSIONS

Unlike endoscopic diagnosis of closed-type atrophic gastritis, that of open-type atrophic gastritis is highly correlated with the histological diagnosis of IM and Cdx2 expression. Endoscopically diagnosed open-type atrophic gastritis and endoscopically diagnosed metaplastic gastritis have similar histological features, which suggests that a high percentage of IM cases are diagnosed as open-type atrophic gastritis by endoscopic examination.

Sonic hedgehog and CDX2 expression in the stomach

Sonic hedgehog (Shh) is an essential regulator of patterning processes throughout development, and CDX proteins act as the master regulators for intestinal development and differentiation. Shh and CDX2 seem to be interdependently linked with cellular differentiation through different signal cascades. We have recently shown that the loss of Shh and aberrant expression of CDX2 in Helicobacter pylori (H. pylori)-associated atrophic gastritis can be modified by H. pylori eradication prior to incomplete intestinal metaplasia. On the other hand, abnormal signaling of the hedgehog pathway has been reported in gastric cancer, especially diffuse-type cancer and advanced gastric cancer, and Shh acts as a proliferation factor in both the normal mucosa and malignant lesions. CDX2 expressed in the early stage of gastric carcinogenesis is associated with the intestinal phenotypic region and thus with a better outcome. However, it remains unclear how Shh and CDX2 are involved with intestinal transformation and further carcinogenesis.

Genetic alterations of the Cdx2 gene in gastric cancer

Gastric atrophy and intestinal metaplasia are generally considered precancerous lesions of the stomach; Cdx2 plays an important role in intestinal metaplasia and gastric carcinogenesis. To elucidate the potential etiological role of the Cdx2 gene in gastric carcinogenesis, we analyzed genetic mutations and allelic loss in the Cdx2 gene of 95 sporadic gastric cancers. We found two somatic missense mutations in the Cdx2 gene, P63L in exon 1 and E204K in exon 2, encoding the caudal-like protein activation region (codon 13-180) and the homeobox domain (codon 188-243) of the gene, in the gastric cancers. In addition, 9 (25.0%) of 36 informative cases showed allelic loss at D13S220 and/or D13S260. In 11 cases with a genetic alteration, Cdx2 nuclear staining was observed only in 8 cases of gastric mucosa with intestinal metaplasia. Loss or reduced expression of the Cdx2 gene in cancer cells was found in two cases with a somatic mutation and in three cases with LOH. Interestingly, all of the cases were intestinal-type gastric cancers. Thus, these results suggest that genetic alterations of the Cdx2 gene may contribute to the loss of Cdx2 expression and to the development of gastric cancer, especially in the intestinal-type.

A clinicopathological study on the expression of cadherin-17 and caudal-related homeobox transcription factor (CDX2) in human gastric carcinoma

AIMS

To analyse the clinicopathological characteristics of the expression of cadherin-17 (CDH17) and caudal-related homeobox transcription factor (CDX2) in human gastric carcinoma, and to evaluate the clinical significance of these two markers in the histological classification and prognosis of gastric carcinoma.

MATERIALS AND METHODS

CDH17, CDX2 protein expression in paraffin-embedded specimens gathered from 166 patients with gastric carcinoma were detected by immunohistochemistry. The association of CDH17, CDX2 protein expression with the clinicopathological characteristics, and with the prognosis of gastric carcinoma were subsequently assessed.

RESULTS

CDH17, nucleus and cytoplasm CDX2 expression were positively expressed in 101/166 (60.8%), 59/166 (35.5%) and 57/166 (34.3%) gastric carcinoma patients, respectively. The expression of both CDH17 and CDX2 is associated with the intestinal-type gastric carcinoma (P<0.01). Positive expression of CDH17 was significantly associated with the depth of gastric wall invasion (P=0.04), lymph node metastasis (P<0.01) and stages of gastric carcinoma (P=0.01). Positive expression of CDX2 in the nucleus was mainly found in male patients (P=0.02), in early stage (P=0.01) and medullary-type gastric carcinoma (P=0.02). There was a negative association between nuclear CDX2 expression and lymph node metastasis of gastric carcinoma (P<0.01). The combined expression of CDH17 and CDX2 was significantly lower in diffuse-type carcinoma than intestinal- or mixed-type carcinoma (P<0.01 and P=0.01, respectively). The patients with CDH17 expression associated with poor prognosis of gastric carcinoma (P<0.01), as opposed to patients with CDX2 expression (P<0.01). The survival rate of patients with CDH17+/CDX2- expression was the lowest (P<0.01), and conjoined expressions of CDH17+/CDX2- and CDH17+/CDX2+ were independent prognostic indicators of gastric carcinoma (both P<0.01).

CONCLUSION

The results suggest that the expression of CDH17 or CDX2 may be an important feature of gastric carcinoma. A combined detection of CDH17/CDX2 co-expression may benefit us in predicting the prognosis of gastric carcinoma.

Intestinal-type cervical adenocarcinoma in situ and adenocarcinoma exhibit a partial enteric immunophenotype with consistent expression of CDX2

Most cases of cervical adenocarcinoma in situ (AIS) and adenocarcinoma are of the usual or endocervical type. However, intestinal types of AIS and adenocarcinoma exist. With an intestinal-type adenocarcinoma in the cervix, the question may arise as to whether one is dealing with a primary cervical neoplasm or direct or secondary spread from an intestinal adenocarcinoma. In organs such as the ovary, urinary bladder, esophagus, and gallbladder, intestinal-type glandular epithelium often expresses enteric markers, but this has hardly been studied in the cervix. The purpose of this study was to investigate whether intestinal-type AIS and adenocarcinoma in the cervix express enteric markers and to ascertain whether these antibodies are of value in the distinction from a metastatic intestinal adenocarcinoma. We compared the immunophenotype of these lesions with that of usual-type AIS and adenocarcinomain the cervix. Cases included were AIS of usual type (n = 6), primary cervical adenocarcinoma of usual type (n = 6), AIS of intestinal type (n = 21), primary cervical adenocarcinoma of intestinal type (n = 3), primary cervical adenocarcinoma with signet ring cells (n = 2), and colorectal adenocarcinoma involving the cervix (n = 5). All cases were stained with cytokeratin (CK) 7, CK20, monoclonal carcinoembryonic antigen (CEA), p16, and CDX2. Staining was categorized as negative, focally positive (<50% cells), or diffusely positive (50% or more cells). Usual-type AIS was always diffusely CK7 positive, typically diffusely CEA and p16 positive, and always CK20 negative. CDX2 was positive in 1 case. All usual cervical adenocarcinomas were diffusely CK7 and p16 positive, and all were immunoreactive with CEA. Five and 2 cases were CK20 and CDX2 positive, respectively. Intestinal-type AIS was diffusely CK7 positive (all cases) and typically CK20 negative and diffusely CEA and p16 positive. All but 1 case exhibited diffuse nuclear positivity with CDX2. In addition, usual-type AIS adjacent to intestinal type was CDX2 positive in 13 of 21 cases. The 3 cases of primary cervical intestinal-type adenocarcinoma were diffusely CK7 positive, focally or diffusely positive with CK20 and CDX2, and focally positive with CEA. One case was diffusely p16 positive, 1 focal and 1 negative. The foci of signet ring cells in the 2 primary cervical adenocarcinomas were diffusely CK7 and p16 positive and negative with CK20 and CDX2. Colorectal adenocarcinomas involving the cervix were typically diffusely positive with CK20, CEA, and CDX2; negative with CK7; and negative or focally positive with p16. Intestinal types of cervical AIS and adenocarcinoma exhibit a partial enteric immunophenotype, usually with diffuse expression of CDX2 and, in some cases, staining with CK20. They maintain their CK7 immunoreactivity and are usually p16 positive. Although there is immunophenotypic overlap, focal staining with CK20 together with diffuse CK7 and sometimes p16 positivity helps to distinguish intestinal types of cervical adenocarcinoma from involvement by a colorectal adenocarcinoma; CEA and CDX2 are of no value in this regard. CDX2 positivity in usual-type AIS adjacent to intestinal type and in occasional cases of pure usual-type AIS may be a reflection of early intestinal differentiation before this is morphologically apparent. Using a set of cases of AIS diagnosed in a single institution over a 7-year period (77 usual type; 13 intestinal type), intestinal type was more likely to be associated with early invasive adenocarcinoma than usual type (31% vs 17%), suggesting that intestinal differentiation may be a risk factor for invasion in premalignant cervical glandular lesions.

Immunohistochemical biomarkers of value in distinguishing primary ovarian carcinoma from gastric carcinoma: a systematic review with statistical meta-analysis

AIMS

To compare the relative risk of antigen expression being detected immunohistochemically in ovarian and gastric carcinoma aggregated from studies performed for diagnostic purposes, with the relative risks of their expression in all patients in the English literature.

METHODS AND RESULTS

Both types of series indicated that cytokeratin (CK) 7 expression was greater and that of CK20 and carcinoembryonic antigen less in ovarian than in gastric carcinoma (P < 0.05). Synthesis of all data available for MUC-2 suggested it was more commonly expressed in ovarian carcinoma, whereas the relative risk in papers that directly compared its expression suggested that it was more common in the gastric carcinoma (P = 0.2, NS). Aggregating all possible data suggested villin was more likely to be expressed in ovarian cancers, whereas studies in which its expression was compared directly in both tumours suggested the opposite. Although statistically significant, patient numbers were small.

CONCLUSION

Provided sufficient numbers of cases are studied, analysis of studies comparing antigen expression for diagnostic purposes in tumours from two body sites is likely to be supported in the wider literature. The design of such comparative studies is informed by aggregating data from single tumour studies.

Animal models of stomach carcinogenesis

Although incidences of stomach cancer have decreased over the past several decades, the disease remains an important public health problem. To identify pathological and molecular biochemical mechanisms, various experimental animal models have been established in rats and mice with chemical carcinogens including N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU). Helicobacter pylori(H. pylori) is one of the most important factors for human stomach disorders, including neoplasia, and the H. pylori-infected and carcinogen-treated Mongolian gerbil (MG) has proven very useful for analyses of underlying processes. The findings with this model support the hypothesis that intestinal metaplasia is important not as a precancerous lesion but rather as a paracancerous condition and that intestinalization of stomach cancer progresses with chronic inflammation. Furthermore, dose-dependent enhancing effects of salt on stomach carcinogenesis could be demonstrated in MGs treated with MNU and H. pylori modifying surface mucous gel layer. H. pylori itself only causes chronic inflammation and acts as a promoter of stomach carcinogenesis in experimental models. Based on the precise pathological diagnosis of stomach lesions such as noncancerous heterotopic proliferative glands (HPG) and adenocarcinomas, a basis for understanding mechanisms of carcinogenesis has been established on which chemoprevention can be modeled.

Gastric adenocarcinoma with chief cell differentiation

A case of adenocarcinoma with chief cell differentiation, a novel entity in the stomach, is presented. An 82-year-old woman who had undergone distal gastrectomy, was scheduled for upper gastrointestinal endoscopy to clarify mechanical ileus. A protruding tumor 16 x 14 x 9 mm in size was found in the cardia of the remnant stomach. Histological examination indicated a well-differentiated tubular adenocarcinoma composed of basophilic columnar or cuboidal cells with occasional coarse eosinophilic granules. Immunohistochemical analysis revealed strong expression of pepsinogens I and II and Runt-related transcription factor gene 3 (RUNX3), characteristic for chief cells, and MUC6 typical for mucous neck cells. However, the tumor cells were negative for the proton pump alpha subunit, a marker for parietal cells. Cdx2 and defensin-5 were not present, confirming the lack of an intestinal phenotype. The cancer cells shared characteristics of a chief cell and a mucous neck cell, resembling an ancestor of these two cell types, so-called 'primitive chief cell' in fundic gland. In line with these data, the cancer was diagnosed as an adenocarcinoma with chief cell differentiation.

Subcellular localization of ATBF1 regulates MUC5AC transcription in gastric cancer

Human gastric epithelium has a unique mucin gene expression pattern, which becomes markedly altered in gastrointestinal disorder. This alteration in mucin expression, including the mucin MUC5AC, may be related to the development and prognosis of gastric cancers, and MUC5AC-positive gastric cancer has been reported to be poor prognosis. However, the molecular mechanism of MUC5AC transcriptional regulation has not been fully elucidated. AT motif-binding factor 1 (ATBF1) is a homeotic transcriptional regulatory factor recently identified as a tumor suppressor gene, and its subcellular localization suggests a link to cell proliferation and differentiation. We investigated the mechanism of MUC5AC transcriptional regulation by ATBF1. In 123 gastric cancer lesions, ATBF1 expressed in the nucleus significantly suppressed MUC5AC expression, as determined by immunohistochemistry. In addition, analysis of the MUC5AC promoter region revealed an AT motif-like element. This element was found to be essential for ATBF1 suppression of MUC5AC promoter activity as shown in a dual luciferase-reporter assay. Over-expressed ATBF1 also significantly suppressed endogenous MUC5AC protein expression in gastric cancer cells. Chromatin immunoprecipitation demonstrated that ATBF1 binds to the AT motif-like element in the MUC5AC promoter. These results indicate that ATBF1 in the nucleus negatively regulates the MUC5AC gene in gastric cancer by binding to an AT motif-like element in the MUC5AC promoter.

Helicobacter pylori infection-negative gastric cancer in Japanese hospital patients: incidence and pathological characteristics

We used Helicobacter pylori sero-positivity and mucosal atrophy as detected by the serum pepsinogen method to identify H. pylori infection-negative gastric cancer patients with or without atrophy. One hundred and six of 748 (14.2%) primary gastric cancer patients were infection-negative by a serum antibody detection system. Further, 121 (16.2%) of the 748 were negative for gastric mucosal atrophy by the pepsinogen method, of whom 15/748 (2.0%) were H. pylori-negative by pepsinogen I level (>70 ng/mL) and pepsinogen I/II ratio (>3.0). Twenty-seven of 782 (3.6%) gastric cancer patients were H. pylori-negative by antibodies and severe atrophy as determined by pepsinogen I level (<30 ng/mL) and pepsinogen I/II ratio (<2.0). H. pylori-negative gastric cancer patients with severe atrophy likely had a previous infection. These results indicate that the actual number of H. pylori-negative patients is 2.0% at minimum and 10.6% (14.2% minus 3.6%) at maximum in the general Japanese population. Five of 15 (33%) cases displaying neither anti-H. pylori antibodies nor atrophy were intestinal-type and 10 (67%) were diffuse-type adenocarcinomas. Thirteen surgical patients with primary gastric cancer displaying neither antibodies nor mucosal atrophy were further analyzed for pathological and phenotypic characteristics. The mucin phenotype was divided into four gastric, five gastric and intestinal, two intestinal and two null types, independent of histological classification. Intestinal phenotype elements were detected by Cdx2 immunohistochemical methods in nine of 13 (70%) cases examined. We conclude that a small fraction of gastric cancer patients displayed multifactorial carcinogenesis without H. pylori infection, indicating that gastric cancer risk still exists in the absence of H. pylori infection, at an incidence of 2.0% at minimum and 10.6% at maximum in the general Japanese population.

Gastric tube cancer: immunohistochemical study of 10 lesions in six patients

BACKGROUND AND AIM

Gastric tube cancer (GTC), defined as carcinoma arising in the reconstructed gastric tube after esophagectomy, has been increasingly reported, but its pathogenesis remains unclear. Therefore, the aim of this study was to examine clinically and pathologically 10 GTCs in six patients.

METHODS

In addition to examination of the clinicopathological features of GTCs, the adjacent gastric tube mucosa was also evaluated immunohistochemically using gastric foveolar markers (MUC5AC and human gastric mucin), pyloric gland markers (MUC6 and M-GGMC-1), and intestinal markers (MUC2 and CD10).

RESULTS

All patients were men and three patients had multiple GTCs. All GTCs were located on the middle to lower portion of the gastric tube. Nine GTCs had tubular and/or papillary adenocarcinoma components, and another was signet-ring cell carcinoma. Intestinal metaplasia was found in non-neoplastic mucosa adjacent to nine GTCs. Metaplastic goblet cells adjacent to five GTCs expressed both gastric and intestinal markers, which were similar to the corresponding GTC cells, indicating a close association between the GTCs and metaplastic goblet cells. The other three GTCs expressed only intestinal markers, which may support the suggestion that the intestinal phenotype is expressed later in cancerous development.

CONCLUSION

Pathogenesis of GTCs could be identical to that of ordinary gastric cancer. Cancerous multiplicity associated with esophageal cancer may also play a role in the development of GTCs.

CDX2 expression is increased in gastric cancers with less invasiveness and intestinal mucin phenotype

OBJECTIVE

CDX2 is an intestinal transcription factor that might be involved in the regulation of proliferation and differentiation of intestinal epithelial cells. It is well known that both gastric and intestinal phenotypic cell markers are expressed in gastric cancers. The aims of this study were to analyze the CDX2 expression and its relationship with the patients' clinicopathological characteristics and the mucin phenotypes by performing immunohistochemistry.

MATERIAL AND METHODS

A total of 259 gastric cancer cases (122 early and 137 advanced cancers) were evaluated histologically and phenotypically. CDX2 expression was assessed by immunohistochemistry.

RESULTS

Increased CDX2 expression correlated with a higher proportion of intestinal-type cancers of Lauren and early gastric cancers (p<0.001 and p<0.001, respectively) and a lower proportion of perineural invasion and lymph node metastasis (p<0.001 and p=0.003, respectively). Increased expressions of intestinal mucin (MUC-2, CD10) and decreased gastric mucin (MUC5AC) were associated with an increased CDX2 expression (p<0.001, p=0.045 and p=0.004, respectively). MUC6 expression was not associated with CDX2 expression. There was a significantly increased CDX2 expression in the intestinal phenotype compared with the other phenotypes (p<0.001).

CONCLUSIONS

These results suggest that CDX2 might be a useful marker in predicting the clinical outcome for patients with gastric cancers.

CDX2 does not suppress tumorigenicity in the human gastric cancer cell line MKN45

CDX2 is a Drosophila caudal-related homeobox transcription factor that is expressed specifically in the intestine. In mice, ectopic expression of CDX2 in the gastric mucosa gives rise to intestinal metaplasia and in one model, gastric carcinoma. In humans, increased CDX2 expression is associated with gastric intestinal metaplasia and tubular adenocarcinomas. These patterns of expression have shown that CDX2 is important for the initiation of intestinal metaplasia in the gastric mucosa, but the role of CDX2 in established gastric cancer remains unclear. We sought to determine whether CDX2 contributes to tumorigenic potential in established gastric cancer. The CDX2 gene in MKN45 gastric carcinoma cells was disrupted using targeted homologous recombination. The resulting CDX2-/- cells are essentially identical to their parental cells, with the exception of CDX2 ablation. We found no significant differences in the proliferation of CDX2-/- cells compared to CDX2+/+ cells, in vitro or in vivo. Molecular analyses show that loss of CDX2 predominantly altered the expression of genes involved in intestinal glandular differentiation and adhesion. However, there were no microscopic differences in tumor differentiation. We conclude that disruption of CDX2 in MKN45 cells does not significantly affect their tumorigenic potential.

Gastric and intestinal phenotypes and histogenesis of advanced glandular stomach cancers in carcinogen-treated, Helicobacter pylori-infected Mongolian gerbils

The Helicobacter pylori-infected Mongolian gerbil (MG) has been established as an appropriate animal model for studies of stomach cancer development. However, there have hitherto been no data on the phenotypic classification of glandular stomach cancers in H. pylori-infected and non-infected MG. We therefore examined the phenotypes of 50 and six advanced glandular stomach cancers in H. pylori-infected and non-infected MG, respectively, as well as adjacent non-neoplastic mucosa, using several gastrointestinal epithelial phenotypic markers. The lesions were divided phenotypically into 21 gastric, 24 gastric-and-intestinal mixed, four intestinal and one null types, with 90.0% of the lesions harboring gastric elements and 56.0% demonstrating intestinal phenotypic expression in H. pylori-infected MG. All six lesions were classified as gastric type in non-infected MG. There was no clear correlation with the presence of intestinal metaplasia in surrounding mucosa. In conclusion, our data suggest that most advanced adenocarcinomas retain a gastric cellular phenotype in the glandular MG stomach. Thus, it might be proposed that intestinal metaplasia is a paracancerous phenomenon rather than a premalignant condition. H. pylori infection may trigger intestinalization of both stomach cancers and non-neoplastic mucosa.

Microsatellite instability is linked to loss of hMLH1 expression in advanced gastric cancers: lack of a relationship with the histological type and phenotype

BACKGROUND

It has been suggested that the prevalence of microsatellite instability (MSI) is high in intramucosal differentiated gastric cancers with gastric foveolar phenotypic expression, and that these tumors are prone to lose their glandular structures and progress to undifferentiated-type lesions. To test this hypothesis, we examined the relationships among human MutL homologue 1 (hMLH1) expression (which is linked to MSI), the phenotype, and the histological type in patients with advanced and intramucosal gastric cancer.

METHODS

We analyzed hMLH1 expression by immunohistochemistry in 70 advanced and 30 intramucosal gastric cancers with histological evaluation and assessment of the phenotype, and Cdx2 expression determined by immunohistochemistry. The MSI status was also examined in 20 cases.

RESULTS

Thirteen (18.6%) advanced and 5 (16.7%) intramucosal gastric cancers were judged to be hMLH1-negative. In the advanced cases, no association was observed between the histological type and the phenotype and loss of hMLH1. In the intramucosal cases, MUC5AC expression was observed in all 5 hMLH1-negative differentiated-type cancers. However, no hMLH1-negative lesions were detected in the intramucosal undifferentiated cancers (0/14; P < 0.05 vs differentiated types). In the advanced cases, MSI-positivity (MSI +) and loss of hMLH1 expression did correlate (P < 0.0001), while no association was observed between MSI +, histological type, and phenotype.

CONCLUSION

Our data support the hypothesis that, phenotypically, some MSI-positive differentiated gastric cancers of gastric foveolar phenotypic expression may easily change, from gastric to intestinal phenotypic expression, also changing, histologically, from differentiated to undifferentiated type with progression.

Clinicopathological significant and prognostic influence of cadherin-17 expression in gastric cancer

Cadherin-17 (CDH17), also called liver-intestine cadherin, is a structurally unique member of the cadherin superfamily. Our serial analysis of gene expression demonstrated that CDH17 was one of the most up-regulated genes in advanced gastric carcinomas. CDH17 expression is known to be regulated by Cdx2. In the present study, we examined the expression of CDH17 in primary gastric carcinoma tissues by immunohistochemistry, and analyzed the correlation of CDH17 expression with clinicopathological characteristics and patients prognosis. CDH17 expression was detected in 63/94 (67%) of gastric adenocarcinomas in addition to intestinal metaplasia. The expression of CDH17 tended to be associated with intestinal type carcinoma, and carcinomas with CDH17 expression was significantly more frequent in advanced stage cases (80%) than in early stage (53%). The prognosis of patients with positive CDH17 expression was significantly poorer than that of the negative cases (P=0.0314). However, multivariate analysis revealed that CDH17 was not an independent prognostic factor. Six of seven cases that showed positive expression of Cdx2 simultaneously expressed CDH17 protein. These results suggested that the expression of CDH17 was characteristic of the advanced gastric carcinoma that is associated with poor prognosis.

Colonic and small-intestinal phenotypes in gastric cancers: Relationships with clinicopathological findings

The clinicopathological significance of colonic and small-intestinal phenotypes has hitherto remained unclear in gastric cancers. The purpose of the present study was therefore to examine 86 gastric carcinomas histologically and phenotypically using several phenotypic markers, including colon-specific carbonic anhydrase 1 (CA1) and sucrase as small-intestine specific marker. Of 86 gastric cancers, sucrase and CA1 expression was observed in 12 (14.0%) and only in two cases (2.3%), respectively, associated with other intestinal markers such as villin and mucin core protein (MUC)2. In the sucrase cases, expression appeared independent of the stage. However, CA1 expression was observed only in two advanced cases. No association was observed between colonic and small-intestinal phenotypes, and lymph node metastasis and postoperative survival in the advanced gastric cancer cases with intestinal phenotypic expression. Cdx2 appeared to be linked to upregulation of both CA1 and sucrase. In conclusion, the data suggest that colonic phenotype occurs rarely in gastric carcinogenesis. Colonic and small-intestinal phenotypes appear with expression of several intestinal phenotypic markers under the control of Cdx2 and presumably other related transcription factors.

Expression of small intestinal and colonic phenotypes in complete intestinal metaplasia of the human stomach

The incomplete intestinal metaplasia (IM) that is reported to be a risk factor for gastric carcinogenesis in man usually features sulfomucin production and thus is considered of colonic type. To cast light on the underlying mechanisms, we here examined the proportions of colonic and small intestinal phenotypes in IM by immunohistochemistry and real-time reverse transcription-polymerase chain reaction at the single isolated gland level. Carbonic anhydrase 1 (CA1) is a specific marker of colonic epithelial cells, whereas sucrase is specific to absorptive cells of the small intestine. Totals of 139 (23.5%) and 452 (76.5%) IM glands were judged to be CA1 positive and CA1 negative, respectively, in resected pyloric mucosa from cancer patients. The average score for MUC5AC in CA1-positive IMs was significantly lower than in CA1-negative counterpart tissue (P<0.0001), whereas the opposite was the case for sucrase (P<0.0001). High iron diamine-Alcian blue staining revealed CA1 expression to coincide with type I complete IM. The expression of CA1 mRNA strongly correlated with that of sucrase-isomaltase, and inversely with that of MUC5AC in isolated IM glands. In conclusion, CA1 could be colocalized with small intestinal proteins such as sucrase, but only rarely with the gastric mucin, MUC5AC. Its expression warrants further study, with the focus on stimulation and/or suppression mechanisms by gastric and intestinal transcription factors.

Coexistence of gastric- and intestinal-type endocrine cells in gastric and intestinal mixed intestinal metaplasia of the human stomach

Intestinal metaplasia (IM) in the human stomach has previously been classified into a gastric and intestinal mixed (GI-IM) and a solely intestinal phenotype (I-IM). The phenotypes of mucous and endocrine cells were evaluated in 3034 glandular ducts associated with chronic gastritis. In the pyloric region, the relative expression of gastric endocrine cell markers, such as gastrin and somatostatin, decreased gradually from glandular ducts with only gastric mucous cell phenotype (G type) to GI-IM toward I-IM, while that of the intestinal endocrine cell markers, glicentin, gastric inhibitory polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) was inversely correlated. In the fundic region, gastrin-positive cells emerged in the pseudo-pyloric and GI-IM glands, whereas I-IM glands did not possess any gastrin-positive cells, suggesting the presence of a distinct pathway of intestinalization. Double staining revealed coexistence of gastrin- and GLP-1-positive cells in the same gland and occasionally in the same cell in GI-IM glands. These results suggest that the phenotypes of endocrine cells are in line with those for mucous counterparts and support the concept that all of the different types of mucous and endocrine cells in normal and IM glands might be derived from a single progenitor cell in each gland.

Sox2 expression in human stomach adenocarcinomas with gastric and gastric-and-intestinal-mixed phenotypes

AIMS

Other than ectopic expression of intestinal transcription factors, Cdx1 and Cdx2, the molecular mechanisms underlying gastric and intestinal phenotypes of human stomach adenocarcinomas have yet to be clarified in detail. We have reported that Sox2, an HMG-box gastric transcription factor, is expressed in normal gastric mucosa and down-regulated in intestinal metaplasia.

METHODS AND RESULTS

We analysed mRNA levels of Sox2 and other differentiation markers in 50 surgically resected stomach adenocarcinomas, immunohistochemically classified into gastric (G), gastric-and-intestinal (GI)-mixed, solely intestinal (I), and null (N) types. Sox2 was found to be transcribed in G and GI-mixed type adenocarcinomas in accordance with MUC5AC and MUC6 expression, while Cdx1 and Cdx2 were up-regulated in GI-mixed and I types along with the expression of MUC2 and villin. In the N type, both gastric and intestinal transcription factors were suppressed. Immunohistochemistry confirmed expression of Sox2 in MUC5AC+ lesions and Cdx2 localization together with MUC2. A stomach adenocarcinoma cell line, KATOIII, demonstrated both MUC5AC and Sox2, although MUC5AC mRNA was not detected in the Sox2+ AGS cell line.

CONCLUSIONS

Sox2 may play an important role in maintaining a gastric phenotype in stomach cancers as well as in normal tissue, in cooperation with other cofactor(s).

Role of Helicobacter pylori in gastric carcinogenesis: the origin of gastric cancers and heterotopic proliferative glands in Mongolian gerbils

Helicobacter pylori infection is well accepted to be a very important factor for the development of gastric carcinogenesis in the human stomach. In Mongolian gerbils treated with chemical carcinogens, H. pylori infection enhances glandular stomach carcinogenesis, and eradication of infection and results in curtailment of enhancing effects, particularly at early stages of associated inflammation. A high-salt diet exacerbates the effects of H. pylori infection on gastric carcinogenesis, and these two factors act synergistically to promote the development of gastric cancers in this animal model. However, the bacterium exerts the greater effects. Early acquisition significantly increases gastric chemical carcinogenesis in Mongolian gerbils, as compared to later infection. While heterotopic proliferative glands, hyperplastic and dilated glands localized beneath the muscularis mucosae, frequently develop with H. pylori infection alone in this animal model, they obviously regress on eradication, suggesting a relation to severe gastritis, rather than a malignant character. Furthermore, endocrine cells, positive for chromogranin A, are observed in the heterotopic proliferative glands, in contrast to cancerous lesions which lack endocrine elements. In conclusion, H. pylori is not an initiator, but rather a strong promoter of gastric carcinogenesis, whose eradication, together with reduction in salt intake, might effectively prevent gastric cancer development.