Predicting ulcerative colitis-associated colorectal cancer using reverse-transcription polymerase chain reaction analysis

BACKGROUND

Widespread genetic alterations are present not only in ulcerative colitis (UC)-associated neoplastic lesions but also in the adjacent normal colonic mucosa. This suggests that genetic changes in nonneoplastic mucosa might be effective markers for predicting the development of UC-associated cancer (UC-Ca). This study aimed to build a predictive model for the development of UC-Ca based on gene expression levels measured by reverse-transcription polymerase chain reaction (RT-PCR) analysis in nonneoplastic rectal mucosa.

PATIENTS AND METHODS

Fifty-three UC patients were examined, of which 10 had UC-Ca and 43 did not (UC-NonCa). In addition to the 40 genes and transcripts previously shown to be predictive for developing UC-Ca in our microarray studies, 149 new genes, reported to be important in carcinogenesis, were selected for low density array (LDA) analysis. The expression of a total of 189 genes was examined by RT-PCR in nonneoplastic rectal mucosa.

RESULTS

We identified 20 genes showing differential expression in UC-Ca and UC-NonCa patients, including cancer-related genes such as CYP27B1, RUNX3, SAMSN1, EDIL3, NOL3, CXCL9, ITGB2, and LYN. Using these 20 genes, we were able to build a predictive model that distinguished patients with and without UC-Ca with a high accuracy rate of 83% and a negative predictive value of 100%.

CONCLUSION

This predictive model suggests that it is possible to identify UC patients at a high risk of developing cancer. These results have important implications for improving the efficacy of surveillance by colonoscopy and suggest directions for future research into the molecular mechanisms of UC-associated cancer.

Gene expression signature and the prediction of ulcerative colitis-associated colorectal cancer by DNA microarray

PURPOSE

Ulcerative colitis (UC) is associated with a high risk of colorectal cancer. To identify genes that could predict the development of cancer in UC, we conducted a DNA microarray analysis using nonneoplastic rectal mucosa of UC patients.

EXPERIMENTAL DESIGN

Gene expression in nonneoplastic mucosa of 53 UC patients were examined. Gene expression profiles were examined using human Genome U133 Plus 2.0 gene chip array (Affymetrix). Among 53 UC patients, 10 had UC-associated cancer (UC-Ca group) whereas 43 did not (UC-NonCa group).

RESULTS

By comparing gene expression profiles of nonneoplastic rectal mucosae between the UC-Ca and UC-NonCa groups, we could identify 40 genes that were differentially expressed between two groups. The list of discriminating genes included low-density lipoprotein receptor-related protein (LRP5 and LRP6). Previous studies suggested that LRP5 and LRP6 expression promotes cancer cell proliferation and tumorigenesis and are considered as candidate oncogenes. In the present study, both LRP5 and LRP6 showed significantly higher expression in the UC-Ca group, which suggests the importance of these genes in the development of UC-associated colorectal cancers. With the 40 selected discriminating genes, we did class prediction of the development of colorectal neoplasms in UC patients. Using the k-nearest neighbor method and the support vector machine, we could predict the development of UC-associated neoplasms with an accuracy of 86.8% and 98.1%, respectively.

CONCLUSIONS

These findings have important implications for the early detection of malignant lesions in UC and may provide directions for future research into the molecular mechanisms of UC-associated cancer.

Tumour budding at the deepest invasive margin correlates with lymph node metastasis in submucosal colorectal cancer detected by anticytokeratin antibody CAM5.2

In the past few years, tumour budding at the invasive margin has been reported as a new risk factor for lymph node metastasis in advanced colorectal cancers, but it is sometimes difficult to detect tumour budding in submucosal colorectal cancer by haematoxylin and eosin staining. We immunohistochemically examined tumour budding at the deepest invasive margin of 56 surgically resected submucosal colorectal carcinomas using anticytokeratin antibody CAM5.2, furthermore checked by AE1/AE3, and determined the relation between tumour budding and clinicopathological factors. Moreover, we used the monoclonal antibody D2-40 for immunohistochemistry to detect lymphatic involvement. Tumour budding was detected in 42 cases (75.0%), and the budding-positive group showed a significantly higher rate of lymph node metastasis (including isolated tumour cells) (16/42 vs 0/14; P=0.004) than the budding-negative group. The sensitivity and negative predictive value of tumour budding alone for lymph node metastasis were superior to those of lymphatic invasion alone. Furthermore, the specificity and positive predictive value of the combination of either lymphatic invasion or tumour budding were superior to those of lymphatic invasion alone. Tumour budding detected immunohistochemically by using CAM5.2 is a newly found risk factor for lymph node metastasis and may help to avoid oversurgery in the future.

Allelic loss analysis of early-stage flat-type colorectal tumors

BACKGROUND

Flat-type colorectal tumors are rare, but are known for their unusual flat morphology and aggressive clinical behavior despite their small size. To identify distinct genetic alterations, loss of heterozygosity (LOH) analysis was performed on microdissected tissues.

MATERIALS AND METHODS

DNA was extracted from multiple microdissected foci in 43 cases of early-stage flat-type colorectal tumors and LOH analysis was performed on 2q, 4q, 5q, 12q, 14q, 15q, 17p, 18q, 18p and 22q.

RESULTS

LOH patterns were detected in one of two forms: (i) homogeneous LOH throughout the microdissected foci, which indicated the early acquisition of LOH; and (ii) heterogeneous LOH, which were detected in a part of analyzed foci. Homogeneous and heterogeneous LOH were most frequently detected on 17p (92%) followed by 18q (81%), 18p (81%), 5q (61%), 22q (51%), 14q (44%), 15q (41%), 2q (39%), 12q (36%) and 4q (32%). Homogeneous LOH was detected most frequently on 17p (68%) followed by 18p (53%), 18q (53%), 22q (34%) and 12q (27%). The average fractional allelic loss (FAL) for heterogeneous and homogeneous LOH was 0.57 and the average FAL for homogeneous LOH was 0.37.

CONCLUSIONS

Early flat-type colorectal tumors frequently shows the early occurrence of multiple LOH including 17p, 18p, 18q and 22q, which is coupled with additional LOH of other loci either simultaneously or in the early clonal progression phase. The extent and sequences of LOH may be the mechanisms responsible for the aggressive clinical behaviors of these tumors.

Pathological appraisal of lines of resection for bile duct carcinoma

BACKGROUND

The aim of this study was to determine the most appropriate line of resection for extrahepatic bile duct carcinoma.

METHODS

A retrospective review was carried out of 253 resected specimens of extrahepatic bile duct carcinoma. Carcinomas were classified histologically as invasive or non-invasive in addition to assessment of the resection margin.

RESULTS

Tumour was present microscopically at the resection margin in 80 (31.6 per cent) of 253 cases, with 46 showing marginal involvement by non-invasive carcinoma, 20 showing invasive carcinoma at a margin, and 14 showing both. Involvement of the resection margin by invasive carcinoma was encountered only when the margin was shorter than 10 mm, whereas non-invasive carcinoma was encountered even when the margin length reached 40 mm. The observed length of microscopic extension of invasive carcinoma beyond the macroscopically evident tumour mass was limited to 10.0 mm. Median microscopic extension of non-invasive carcinoma beyond the mass was 10 mm (75th percentile 19.5 and 14.5 mm in proximal and distal directions respectively; maximum 52 mm). Margins of 20 mm could be assured to be negative proximally in 89.0 per cent of cases and distally in 93.8 per cent.

CONCLUSION

For eradication of invasive extrahepatic bile duct carcinoma, a 10-mm margin is required. However, additional removal of any non-invasive component requires a 20-mm margin. These guidelines should be followed in any operation performed with curative intent.

Superficial depressed-type cancer monitored by colonoscopy through the early phase of invasion

Although previous retrospective reports have demonstrated the developmental course of several colorectal tumors, the natural history and progression of depressed carcinoma, especially in the early stage, remains obscure. We report a case of superficial depressed tumor in the transverse colon in a 71-year-old man, which did not change in size and gross configuration through prospective colonoscopic observation over a period of 19 months but which was finally diagnosed as early-stage submucosal invasive cancer. Most depressed cancers have been supposed to arise de novo and grow rapidly, showing aggressive behavior when 10 mm or less in size. However, this case report may suggest that even a depressed tumor may grow to approximately 10 mm within the mucosal layer over a few years and that the growth of colorectal tumors, whether they are polypoid or depressed in configuration, might be fairly slow.

Sensitivity of biopsy site in evaluating regression of gastric atrophy after Helicobacter pylori eradication treatment

BACKGROUND

Helicobacter pylori infection is a major cause of the progress of gastric glandular atrophy, a high-risk background factor in the development of gastric cancer. Regression of gastric atrophy is critical to prevention of cancer by H. pylori eradication treatment. However, it is controversial whether gastric atrophy regresses after H. pylori eradication.

AIM

To determine the most sensitive and appropriate biopsy site for evaluation of regression of atrophy after treatment.

SUBJECTS AND METHODS

Thirty-eight patients who showed regression of gastric atrophy in histology after treatment were investigated. Four biopsy specimens from the lesser and greater curvatures in the antrum and corpus were evaluated before and after treatment according to the Updated Sydney System.

RESULTS

Regression of atrophy after treatment was seen in 30 of 38 biopsy specimens from the lesser curvature of the corpus (79%), and this site was most sensitive. Odds ratio of this site to the others was 8.28. Regression of atrophy in this site was observed at 12.2 months in the younger patients and 15.9 months in the elder patients.

CONCLUSION

Biopsy sampling from the lesser curvature of the corpus is the most sensitive and appropriate for evaluation of regression of gastric atrophy after H. pylori eradication treatment.

Bcl-2 expression and frequency of apoptosis correlate with morphogenesis of colorectal neoplasia

AIM

To investigate whether the expression of apoptosis and cell proliferation related proteins is related to the macroscopic form of colorectal neoplasia.

METHODS

The extent of apoptosis, using the 3' end DNA labelling method, and the immunohistochemical expression of cell proliferation (Ki-67) and apoptosis related proteins (Bcl-2, Bak, and p53) were investigated in 64 colorectal adenomas and 22 early carcinomas extending no further than the upper submucosal region. The specimens were classified into three types of macroscopic form (polypoid, flat, and depressed).

RESULTS

The Ki-67 labelling index and the Bak score did not differ significantly among each macroscopic form. In contrast, the apoptotic index and the Bcl-2 score changed significantly according to the macroscopic forms. Compared with polypoid and flat tumours, depressed tumours had a significantly lower apoptotic index (2.84, 2.28, and 1.44, respectively) and a significantly lower Bcl-2 score (3.18, 2.70, and 1.64, respectively). The proliferation/apoptosis ratio was significantly lower in polypoid tumours than in the other two macroscopic forms. The Bcl-2 score became significantly lower as the tumours flattened or took on a depressed form. Immunohistochemical p53 overexpression did not correlate with the macroscopic forms.

CONCLUSIONS

These results suggest that differences in both Bcl-2 expression and apoptosis may play an important role in the morphogenesis of colorectal neoplasia.

Heterogeneity of p53 mutational status in the superficial spreading type of early gastric carcinoma

BACKGROUND

The superficial spreading type of gastric carcinoma may originate from either a single cellular clone or from several different clones; this issue remains controversial. Indeed, the p53 gene has been shown to play an important role in gastric carcinogenesis, but there have been only a few reports on the heterogeneity of gastric carcinoma with respect to the p53 gene.

METHODS

We analyzed seven cases of the superficial spreading type of gastric submucosal carcinomas (80 lesions; 10 to 17 per case) which showed different histological types and/or different p53 protein staining patterns. Direct sequences of polymerase chain reaction products were used for the analysis.

RESULTS

p53 Gene heterogeneity in mucosal carcinoma lesions was detected in three cases. However, in all of the cases, the p53 mutational pattern was identical to that found in the submucosal carcinoma lesions. In the heterogeneous cases, the mutation in the submucosal carcinoma was one of the mutation patterns found among the mucosal carcinoma lesions. More precisely, the mutational pattern of both submucosal carcinoma lesions and the mucosal lesions located just above them, was identical.

CONCLUSION

These data suggest that, with regard to the p53 gene, in some superficial spreading types of gastric carcinomas, there are various subclones in the mucosal carcinoma; one of these subclones becomes predominant through clonal selection, and, thus, invades the submucosa.

Malignant islet cell tumor projecting into the main pancreatic duct

We report herein a rare case of islet cell tumor showing a unique growth pattern in a patient who developed repeated acute pancreatitis as the tumor's initial symptom. Preoperative imaging examinations showed dilatation of the main pancreatic duct (MPD) and cysts around the pancreatic tail. A distal pancreatectomy with splenectomy was performed because the pancreatitis was localized in the distal pancreas and was not controlled by various drug therapies. Grossly, the tumor consisted of two component parts: a markedly infiltrative part in the pancreatic parenchyma, and a papillary elevated part in the MPD. The MPD was obstructed by the tumor spreading widely along the distal MPD. Microscopically, the tumor was composed entirely of islet cell tumors (nonfunctioning), with several foci of venous and lymphatic involvement. Based on its growth behavior, we assumed that the tumor may have arisen from the MPD or from islet cells closely adjacent to the MPD. The patient's postoperative course was uneventful and he is doing well 2 years after the operation. We discuss the growth pattern of the tumor and the cause of the pancreatitis.

Mutations of p53 in morphologically non-neoplastic mucosa of long-standing ulcerative colitis

Two cases of ulcerative colitis (UC)-associated carcinoma or dysplasia and morphologically non-neoplastic mucosa with p53 protein overexpression (MNNM-p53OE) were selected. DNA was extracted from the paraffin blocks of these lesions and exons 5 - 8 of the p53 gene were analyzed by PCR and direct sequencing. In addition, mutations in K-ras codon 12 were analyzed by PCR-RFLP methods. MNNM-p53OE was located surrounding and adjoining a coexisting carcinoma and / or dysplasia. A p53 mutation was detected in 12 / 22 (54.5%) MNNM-p53OE samples, 4 / 8 (50%) dysplasia samples and 8 / 8 (100%) carcinoma samples. The p53 mutations detected in MNNM-p53OE were identical to those demonstrated in the adjoining carcinoma and / or dysplasia. No K-ras codon 12 mutation was detected in any of the samples. These results indicate that MNNM-p53OE may share an identical clonal linkage with a coexisting carcinoma and / or dysplasia, and may be an initial and submorphological form of UC-associated neoplasia. Recognition of MNNM-p53OE in biopsy specimens may help to identify patients with UC at risk of developing colorectal carcinoma.

Heterogeneity of p53 mutational status in intramucosal carcinoma of the colorectum

The aim of this study was to elucidate whether or not p53 genetic heterogeneity would occur while colorectal carcinoma was limited to the mucosa. Eight cases of endoscopically resected colorectal intramucosal carcinomas were analyzed to determine the p53 gene sequence (exons 5 to 8). Six out of 8 cases showed p53 gene mutations, and in all of them, the mutational status was heterogeneous. In 4 cases, mutated codons were heterogeneous as well. These data indicate that p53 gene alterations in colorectal carcinomas occur and diverge at the stage of intramucosal carcinoma, supporting our previously proposed hypothesis that colorectal carcinomas can be composed of various subclones as regards p53 gene mutation, while the carcinoma is limited to the mucosa, and one of these subclones commences invasion to the submucosa after clonal selection, thus generating a monoclonal invasive carcinoma.

Cellular phenotypes of differentiated-type adenocarcinomas and precancerous lesions of the stomach are dependent on the genetic pathways

To elucidate the relationship between genetic alterations and cellular phenotypes in differentiated-type carcinomas and precancerous lesions of the stomach, mutations of p53, APC and K-ras genes were examined, as well as microsatellite instability (MSI), in 52 tumours of the stomach. Tumours were selected with the following phenotypical features, using mucin histochemical and immunohistochemical analyses, in addition to their morphological features: (1) tumours with an extremely well-preserved gastric foveolar phenotype (foveolar-type); (2) tumours with an extremely well-preserved complete-type intestinal metaplastic phenotype (CIM-type); and (3) ordinary tumours without extreme phenotypes (ordinary-type). MSI occurred in 45% of foveolar-type, 24% of ordinary-type, and 0% of CIM-type tumours. p53 gene alterations occurred in 5% of foveolar-type, 18% of ordinary-type, and 31% of CIM-type. APC gene alterations were detected in 9% of foveolar-type, 6% of ordinary-type, and 0% of CIM-type. No K-ras gene mutation was detected in any of the three types. These results indicate that the genetic pathways are quite different among the phenotypes of tumours of the stomach. The 'mutator pathway', characterized by MSI, plays an important role in the tumourigenesis of foveolar-type, but not CIM-type tumours. The 'suppressor pathway', represented by p53 alteration, could participate in the tumourigenesis of the CIM-type, but is rare in foveolar-type tumours.

Cellular phenotypes of differentiated-type adenocarcinomas and precancerous lesions of the stomach are dependent on the genetic pathways

To elucidate the relationship between genetic alterations and cellular phenotypes in differentiated-type carcinomas and precancerous lesions of the stomach, mutations of p53, APC and K-ras genes were examined, as well as microsatellite instability (MSI), in 52 tumours of the stomach. Tumours were selected with the following phenotypical features, using mucin histochemical and immunohistochemical analyses, in addition to their morphological features: (1) tumours with an extremely well-preserved gastric foveolar phenotype (foveolar-type); (2) tumours with an extremely well-preserved complete-type intestinal metaplastic phenotype (CIM-type); and (3) ordinary tumours without extreme phenotypes (ordinary-type). MSI occurred in 45% of foveolar-type, 24% of ordinary-type, and 0% of CIM-type tumours. p53 gene alterations occurred in 5% of foveolar-type, 18% of ordinary-type, and 31% of CIM-type. APC gene alterations were detected in 9% of foveolar-type, 6% of ordinary-type, and 0% of CIM-type. No K-ras gene mutation was detected in any of the three types. These results indicate that the genetic pathways are quite different among the phenotypes of tumours of the stomach. The 'mutator pathway', characterized by MSI, plays an important role in the tumourigenesis of foveolar-type, but not CIM-type tumours. The 'suppressor pathway', represented by p53 alteration, could participate in the tumourigenesis of the CIM-type, but is rare in foveolar-type tumours.

Frequent hypermethylation of the hMLH1 gene promoter in differentiated-type tumors of the stomach with the gastric foveolar phenotype

Hypermethylation of the hMLH1 mismatch repair gene promoter has been revealed to lead to microsatellite instability (MSI). Previously, we demonstrated a high prevalence of MSI in differentiated-type gastric tumors showing distinct features of gastric foveolar epithelium (foveolar type). To clarify the significance of hMLH1 promoter hypermethylation in the development of this tumor type, we studied promoter methylation status and expression of hMLH1 in foveolar-type tumors and their surrounding non-neoplastic mucosae, as well as in tumors with other cellular phenotypes. The results were compared to MSI status. After phenotypical analyses using mucin histochemistry and immunohistochemistry, 41 differentiated-type tumors with distinct cellular phenotypes were classified into three categories: foveolar type, intestinal type (tumors with the distinct cellular phenotype of the intestine), and combined type (tumors with both foveolar and intestinal phenotypes). Methylation-specific polymerase chain reaction (MSP) was performed to determine the methylation status of hMLH1 promoter. hMLH1 protein expression was immunohistochemically examined. MSI was detected in 57% of the foveolar type, 8% of the intestinal type, and 67% of the combined-type tumors. Hypermethylation of hMLH1 promoter was found in 74% of the foveolar type, 33% of the intestinal type, and 83% of the combined-type tumors. Of 18 MSI-positive tumors, all but one were hypermethylated. Methylation status of hMLH1 promoter correlated well with protein expression in foveolar-type tumors. Moreover, hypermethylation was also detected frequently (71%) in the non-neoplastic surrounding mucosa of the hypermethylated tumors. Hypermethylation of hMLH1 promoter is an initial, vital event in the development of foveolar-type tumors of the stomach.

Early colorectal cancer with special reference to the superficial nonpolypoid type from a histopathologic point of view

The incidence and histopathologic characteristics of nonpolypoid (superficial type) early colorectal carcinomas were studied and compared with those of the polypoid type. The superficial type was subclassified as elevated (type IIa), type IIa with central depression (type IIa + IIc), plain (type IIb), depressed (type IIc), and IIc with marginal elevation (type IIc + IIa). The superficial type comprised 22% and 27% of intramucosal and submucosal carcinomas, respectively. Pure type IIb was not found, and there were only three pure type IIc lesions. Type IIa + IIc and IIc + IIa (and IIc) showed a significantly higher rate of submucosal invasion among the small tumors (59% and 71% less than 20 mm, respectively) compared to the polypoid type; type IIa showed no significant difference. The incidence of lymph node metastasis among submucosal carcinomas showed no significant difference between the superficial type and the polypoid type. About 64% and 52% of type IIa and IIa + IIc tumors accompanied residual adenoma, suggesting that they originated from small, flat adenomas through the adenoma-carcinoma sequence, whereas type IIc + IIa (and IIc) did not have an adenomatous component, implying that they arose de novo or originated through an adenoma-carcinoma sequence at a smaller size than the type IIa and IIa + IIc lesions. Superficial-type early colorectal carcinomas are not rare, and they are not uniform in nature. Rapid growth and invasion to the submucosa is characteristic of superficial-type lesions with a central depression, and only superficial depressed (type IIc + IIa, IIc) lesions can arise de novo. Although they grow rapidly to invade the submucosa, it cannot be said that they show more aggressive behavior than the polypoid type.

When can complete regression of low-grade gastric lymphoma of mucosa-associated lymphoid tissue be predicted after helicobacter pylori eradication?

AIMS

Recent studies suggest that primary low-grade gastric lymphomas of mucosa-associated lymphoid tissue (MALT) are cured in many cases between 1 and 18 months after H. pylori eradication. The aim of this study is to elucidate when complete regression (CR) of MALT lymphoma can be histologically predicted after H. pylori eradication.

METHODS AND RESULTS

Twenty-one patients with low-grade gastric MALT lymphoma were treated with triple therapy (amoxicillin, clarythromycin and proton pump inhibitor) for 14 days. Subsequently, they were followed up by sequential endoscopy and biopsy (number of biopsy specimens for each endoscopy is 3-8, with an average of 4) from 91 to 657 days (average: 309 +/- 165 days). Eradication of H. pylori infection was achieved in all patients. Nine patients were free of lymphoma at 1 to 2 months after eradication and remained in CR at 163-657 days. Twelve patients showed residual lymphoma at 1 to 2 months after eradication. Five out of 12 patients revealed only one or two small foci of lymphoma-cell aggregation and showed a high incidence (80%) of CR at the latest biopsy (135-434 days, average 276 +/- 115 days after eradication), while seven patients showed diffuse remains of lymphoma cells and indicated CR in only one case (14%) at 362 days, partial regression in five cases at 130-431 days (average 227 +/- 114 days), and no change in one case at 91 days after eradication.

CONCLUSIONS

: These results suggest that CR of low-grade MALT lymphoma can be predicted at 1 to 2 months after eradication therapy by checking histological changes of MALT lymphoma cells.

Different amounts of K-ras mutant epithelial cells in pancreatic carcinoma and mass-forming pancreatitis

Clinically, differential diagnosis of pancreatic carcinoma (PC) and so-called "mass-forming pancreatitis (MFP)" is difficult. We analyzed the amount, ductal level, and K-ras mutation of ductal hyperplasia and intraductal carcinoma in surgically resected cases of MFP (n = 18) and PC (n = 16). DNAs extracted from microdissected epithelial foci were analyzed for K-ras codon 12 mutation by nested polymerase chain reaction and restriction fragment length polymorphism. The histology of MFP showed severe destruction of exocrine tissue and pancreatic stones and/or protein plugs (72%, 13 of 18 cases) in mostly peripheral ducts. The average basal membrane lengths of nonpapillary and papillary hyperplasia in cases of carcinoma were about 4 and 15 times more than those of MFP, respectively. The frequency of K-ras mutation in hyperplastic foci increased from nonpapillary [six (27%) of 22] to papillary foci [16 (64%) of 25] in K-ras mutant PCs, but there was no difference between nonpapillary [one (6%) of 18] and papillary foci (none of 19) in K-ras wild-type PCs, and also between nonpapillary (none of 24) and papillary foci [one (7%) of 14] in MFPs.

Stromal sialyl Le(a) expression is correlated with vascular invasion of human gallbladder adenocarcinoma

Sialyl Le(a) antigen (CA19-9), a member of a family of high molecular weight glycoproteins, was originally described as a gastrointestinal- and pancreatic-specific tumor marker. Recent studies have demonstrated that sialyl Lea is a ligand for E-selectin and may play an important role in tumor metastasis. However, expression patterns of sialyl Le(a) have not yet been established in human gallbladder carcinomas. In this study, we examined sialyl Le(a) expression in human gallbladder adenocarcinoma and its clinicopathological significance. Sialyl Le(a) immunoreactivity was detected not only in cancer cells (cytoplasmic type; 68.5%, 37/54) but also in cancer stroma (stromal type; 46.3%, 24/54). According to TNM classification, stromal sialyl Le(a) expression was detected in 60. 0% (24/40) and 7.1% (1/14) of the T2-4 and T1 cancers, respectively (p<0.01). Stromal sialyl Le(a)-positive gallbladder cancers frequently showed lymphatic invasion, venous invasion and lymph node metastasis (62.9%, 62.5% and 70.0%, respectively) (p<0.01). These observations suggested that sialyl Le(a) expression plays important roles in vascular invasion and metastasis of human gallbladder adenocarcinomas.

Cellular phenotypes of differentiated-type adenocarcinomas and precancerous lesions of the stomach are dependent on the genetic pathways

To elucidate the relationship between genetic alterations and cellular phenotypes in differentiated-type carcinomas and precancerous lesions of the stomach, mutations of p53, APC and K-ras genes were examined, as well as microsatellite instability (MSI), in 52 tumours of the stomach. Tumours were selected with the following phenotypical features, using mucin histochemical and immunohistochemical analyses, in addition to their morphological features: (1) tumours with an extremely well-preserved gastric foveolar phenotype (foveolar-type); (2) tumours with an extremely well-preserved complete-type intestinal metaplastic phenotype (CIM-type); and (3) ordinary tumours without extreme phenotypes (ordinary-type). MSI occurred in 45% of foveolar-type, 24% of ordinary-type, and 0% of CIM-type tumours. p53 gene alterations occurred in 5% of foveolar-type, 18% of ordinary-type, and 31% of CIM-type. APC gene alterations were detected in 9% of foveolar-type, 6% of ordinary-type, and 0% of CIM-type. No K-ras gene mutation was detected in any of the three types. These results indicate that the genetic pathways are quite different among the phenotypes of tumours of the stomach. The 'mutator pathway', characterized by MSI, plays an important role in the tumourigenesis of foveolar-type, but not CIM-type tumours. The 'suppressor pathway', represented by p53 alteration, could participate in the tumourigenesis of the CIM-type, but is rare in foveolar-type tumours.

Nuclear translocation of beta-catenin in colorectal cancer

Post-translational stabilization of beta-catenin through mutation of the adenomatous polyposis coli (APC) gene has been proposed as an early step in colorectal carcinogenesis. Beta-catenin may translocate from the cytoplasm to the nucleus, where it might serve as a transcriptional factor to stimulate tumour formation. We investigated intracellular localization of beta-catenin in sporadic colorectal adenomas and cancers as well as familial adenomatous polyposis (FAP). Nuclear over-expression of beta-catenin was observed in 35% (7/20) of intramucosal cancers and 42% (23/55) of invasive cancers but was not seen in any adenomas from sporadic or FAP cases. Cytoplasmic beta-catenin in adenomas was significantly higher than that of normal mucosa in both sporadic and FAP cases. The cytoplasmic intensity index of cancers was significantly higher than that of sporadic adenomas, but the index was not correlated with nuclear expression in cancers. These findings suggest that nuclear translocation of beta-catenin is involved in development of intramucosal cancer rather than adenoma, independent of APC mutations. Cytoplasmic accumulation of beta-catenin may occur in adenomas, but it remains to be determined whether this is a cause or a consequence of colorectal cancer.

Ovarian gonadoblastoma with mixed germ cell tumor in a woman with 46, XX karyotype and successful pregnancies

An extremely rare case of unilateral gonadoblastoma with mixed germ cell tumor arising in the ovary of a 27-year-old woman with 46,XX karyotype and two successful pregnancies is reported. The mixed germ cell tumor was composed of choriocarcinoma, embryonal carcinoma, yolk sac tumor, immature teratoma and dysgerminoma. The patient has been well, without evidence of disease for over 10 years since her first surgery and adjuvant chemotherapy.

The common 18-base pair deletion at codons 418-423 of the E-cadherin gene in differentiated-type adenocarcinomas and intramucosal precancerous lesions of the stomach with the features of gastric foveolar epithelium

Alterations of the E (epithelial)-cadherin gene are often involved in undifferentiated-type carcinomas of the stomach, but not in the differentiated type. Recently, it was recognized that certain differentiated-type carcinomas possess the features of gastric foveolar epithelium. Such carcinomas are closely linked with undifferentiated-type carcinomas. Nineteen lesions (ten differentiated-type carcinomas and nine precancerous lesions) with a predominant gastric foveolar phenotype, as determined not only by mucin histochemistry and immunohistochemistry but also by morphology, were analysed for mutations of the E-cadherin gene using the nested polymerase chain reaction single-strand conformation polymorphism method. E-cadherin gene mutation was detected in 4 of 19 lesions (21 per cent) (three precancerous and one cancerous). Sequencing revealed an 18 bp deletion corresponding to codons 418-423 of exon 9 common to all four lesions. This mutation was previously reported in an advanced carcinoma of undifferentiated type. The results suggest that these tumours progress to undifferentiated-type carcinomas through loss of E-cadherin function.

Clinical significance of MUC1 and MUC2 mucin and p53 protein expression in colorectal carcinoma

BACKGROUND

Up-regulation of MUC1, down-regulation of MUC2 and p53 overexpression are seen in colorectal carcinomas. However, there have been few reports about the associations between MUC1, MUC2 and p53 expression and metastatic potential. The aim of this study was to investigate MUC1, MUC2 and p53 expression in colorectal carcinoma with special reference to regional and distant metastasis.

METHODS

Eighty-six colorectal carcinomas were collected from patients undergoing tumor resection. Sections were used for MUC1, MUC2 and p53 immunostaining. Cancers were regarded as MUC1 or MUC2 positive when the positive cells were beyond 30% of cancer cells. Cancers with diffuse or nested patterns were regarded as having p53 overexpression.

RESULTS

Of 86 cancers, 37 (43%) were MUC1 positive, 28 (33%) were MUC2 positive and 59 (69%) showed p53 overexpression. A difference was observed only in the frequency of MUC1 positivity with respect to depth of tumor invasion. Neither depth of tumor invasion nor histological differentiation had a positive correlation with MUC1, MUC2 and p53 overexpression. The frequency of MUC1 positive cells in Dukes' C and D tumors was significantly higher than that in Dukes' A and B tumors. The frequency of MUC1 positivity in tumors with hepatic involvement was significantly higher than that in tumors without hepatic involvement (100 vs 39%; p < 0.01). There was no difference in the frequency of MUC2 or p53 positivity in Dukes' stage or hepatic metastasis. MUC1 immunoreactivity of the surface was identical with that of the whole tumor in 81% (70/86) of carcinomas, MUC 2 in 87% and p53 in 100%.

CONCLUSIONS

The results suggest that up-regulation of MUC1 is involved in the progression from the non-metastatic to the metastatic stage and that p53 abnormality is not directly involved in it. The data also imply that immunostaining of preoperative biopsy samples is useful for evaluating the immunoreactivity of the whole tumor.

Significance of immunohistochemically demonstrated micrometastases to lymph nodes in esophageal cancer with histologically negative nodes

BACKGROUND

We examined the prevalence, patterns, and clinical significance of nodal micrometastases in patients with esophageal cancer.

METHODS

Cervical, mediastinal, and abdominal lymph nodes systematically removed from 37 patients without conventional histologic evidence of lymph node metastasis from esophageal squamous cell carcinoma were immunohistochemically examined to detect cells that were stained for cytokeratins by the monoclonal antibody cocktail AE1/AE3. Postoperative care and survival were compared in cases with and without such micrometastases.

RESULTS

Nodal micrometastases were found in 14 of 37 patients (38%). Among these patients, 9, 7, and 4 had micrometastases to abdominal, mediastinal, and cervical lymph nodes, respectively. Postoperative tumor recurrence was significantly more frequent in patients with micrometastases (50%) than in those without (9%, P = .008). Overall and relapse-free survival in the former group was significantly worse than in the latter group (P = .042 and P = .002, respectively). Nodal micrometastases had an independent prognostic importance for relapse-free survival as determined by multivariate analysis.

CONCLUSIONS

Metastatic tumor cells are frequently present in lymph nodes, even in patients without histologic evidence of nodal metastasis from esophageal cancer. Nodal micrometastases indicates a poorer prognosis after a curative esophagectomy procedure in histologically node-negative cases.

The common 18-base pair deletion at codons 418-423 of the E-cadherin gene in differentiated-type adenocarcinomas and intramucosal precancerous lesions of the stomach with the features of gastric foveolar epithelium

Alterations of the E (epithelial)-cadherin gene are often involved in undifferentiated-type carcinomas of the stomach, but not in the differentiated type. Recently, it was recognized that certain differentiated-type carcinomas possess the features of gastric foveolar epithelium. Such carcinomas are closely linked with undifferentiated-type carcinomas. Nineteen lesions (ten differentiated-type carcinomas and nine precancerous lesions) with a predominant gastric foveolar phenotype, as determined not only by mucin histochemistry and immunohistochemistry but also by morphology, were analysed for mutations of the E-cadherin gene using the nested polymerase chain reaction single-strand conformation polymorphism method. E-cadherin gene mutation was detected in 4 of 19 lesions (21 per cent) (three precancerous and one cancerous). Sequencing revealed an 18 bp deletion corresponding to codons 418-423 of exon 9 common to all four lesions. This mutation was previously reported in an advanced carcinoma of undifferentiated type. The results suggest that these tumours progress to undifferentiated-type carcinomas through loss of E-cadherin function.

Differences in mucus and K-ras mutation in relation to phenotypes of tumors of the papilla of vater

BACKGROUND

To investigate their hypothesis that K-ras mutation is correlated with epithelial metaplastic change, the authors classified tumors of the papilla of Vater histologically and according to mucin histochemistry as either intestinal type (complete or incomplete) or pancreaticobiliary type (ordinary or metaplastic) and analyzed the tumors for K-ras mutation during tumorigenesis.

METHODS

Fifty-two tumors of the papilla of Vater (5 adenomas, 24 carcinomas with adenoma component, and 23 carcinomas) obtained from surgical specimens were evaluated. The mucus phenotype was analyzed with MUC1, MUC2, MUC5AC, sialyl Lewis(a) (CA 19-9), HID-AB, and ConA III stainings. K-ras codon 12 mutation was detected by nested polymerase chain reaction (PCR)-restriction fragment length polymorphism and enriched PCR-enzyme-linked minisequence assay.

RESULTS

The presence of adenoma component and intramucosal tumor spreading in the ampulloduodenum was significantly higher in intestinal-type tumors (90%, 27 of 30 tumors, and 100%, 30 of 30 tumors, respectively) than in pancreaticobiliary-type tumors (9%, 2 of 22 tumors, and 23%, 5 of 22 tumors, respectively) (P < 0.0001). MUC2 expression was positive in intestinal-type tumors but not in pancreaticobiliary-type tumors. K-ras mutation rates for incomplete intestinal-type tumors (78%, 7 of 9) and metaplastic pancreaticobiliary-type tumors (64%, 7 of 11), which showed MUC5AC (gastric-type apomucin) expression in cytoplasm, were significantly higher than in complete intestinal-type tumors (33%, 6 of 21) and ordinary pancreaticobiliary-type tumors (18%, 2 of 11) (P = 0.01 and P = 0.03, respectively). In pancreaticobiliary-type tumors, K-ras mutation was more frequently recognized in tumors with ampullopancreatic duct tumor extension (75%, 3 of 4) than in those with ampullobiliary duct extension (0%, 0 of 6) (P = 0.01). Furthermore, sequences of K-ras codon 12 were common in 17 carcinomas with adenoma component that were analyzed for both adenoma and carcinoma.

CONCLUSIONS

Tumors of the papilla of Vater can be classified histologically as either intestinal type or pancreaticobiliary type, and they have different features according to tumor location, association with adenoma, and MUC2 expression. Furthermore, K-ras mutation is supposed to be associated with tumors arising in the area from the ampulloduodenum to the ampullopancreatic duct, with metaplastic mucus occurring in both intestinal and pancreaticobiliary types.

Histological and genetic changes in malignant transformation of gallbladder adenoma

DESIGN

Elucidate the histological and genetic changes in malignant transformation of adenoma of the gallbladder.

MATERIALS AND METHODS

Forty-three adenomas and 20 intramucosal tumors of carcinoma-in-adenomas were studied for histological and genetic changes (particularly K-ras mutation and p53 protein overexpression by immunohistochemistry) in malignant transformation. The genetic changes were compared with those of 164 carcinomas without anomalous union and 17 carcinomas with anomalous union of pancreatico-biliary duct.

RESULTS

Atypical cell foci, i.e. spindle cell foci, were observed only in the adenoma area, with a frequency of 23% in 39 adenomas, and of 45% in 20 tumors of carcinoma-in-adenoma. 129 of 130 spindle cell foci examined were negative for Ki-67 staining and all the spindle cell foci were negative for p53 stain. K-ras mutation and p53 overexpression were not found in all adenomas, pure and with carcinoma i.s., and only one carcinoma (1/16, 6%) with adenoma showed p53 overexpression. K-ras mutation was low (10%, 4/40) in carcinomas without adenoma, but high in carcinomas with anomalous union of pancreatico-biliary duct. While, p53 overexpression was high and similar in carcinomas with and without anomalous union.

CONCLUSIONS

These results suggest that there are three distinct pathways in gallbladder carcinogenesis; that is, de novo carcinoma develops from a predominant p53 alteration with low K-ras mutation, de novo carcinoma with anomalous union from K-ras mutation and p53 mutation, and carcinoma-in-adenoma from K-ras-, p53-, and probably APC-gene-related, as yet unknown, alteration.

Multiple K-ras mutations in hyperplasia and carcinoma in cases of human pancreatic carcinoma

Mucous cell hyperplasia (MCH) has been considered an important precursor of pancreatic ductal carcinoma based on histological and molecular research, although various K-ras mutations rates are seen among cases with pancreatic carcinoma, chronic pancreatitis and normal pancreas, with a wide range of histological characters. To investigate the premalignant potential of MCH and the multicentricity of pancreatic carcinoma, we analyzed K-ras mutation at codon 12 in carcinoma foci of 82 cases of surgically-resected pancreatic carcinoma [67 solid-type carcinomas (SCs) and 15 ductectatic-type carcinomas (DCs)], as well as in both MCH and carcinoma foci in 42 cases (30 SCs and 12 DCs), using an enriched polymerase chain reaction (PCR)-enzyme linked mini-sequence assay (ELMA). K-ras mutation was recognized in 85% (57/67) of SCs and 73% (11/15) of DCs, and multiple K-ras mutations in 12% (8/67) of SCs and in 20% (3/15) of DCs. Multiple K-ras mutations were also recognized in MCHs in 47% (14/30) of SCs and in 42% (5/12) of DCs. Moreover, the same sequence at K-ras codon 12 in MCH and carcinoma was identified in 76% (32/42) of carcinoma cases and it was more frequently recognized in hyperplasias with histological atypia (51%, 37 of 72 foci) than those without atypia (24%, 16 of 68 foci) (P<0.0007). These results further support the idea of multicentric carcinogenesis and premalignant potential of atypical hyperplasia in the human pancreas, although about half of the hyperplasias around carcinomas were not thought to be direct precursors.

Immunohistochemical staining patterns of MUC1, MUC2, MUC4, and MUC5AC mucins in hyperplastic polyps, serrated adenomas, and traditional adenomas of the colorectum

We studied the distribution of the four human apomucins MUC1, MUC2, MUC4, and MUC5AC in hyperplastic polyps, serrated adenomas, and traditional adenomas of the colorectum using immunohistochemical techniques, with the aim of comparing and contrasting their patterns of expression. A series of 12 hyperplastic polyps, 27 serrated adenomas, and 20 traditional adenomas was studied. No significant change in apomucin expression was observed in traditional adenomas compared with normal colorectal epithelium, except for MUC5AC, which was present in 12 of the adenomas (60%) and only 20% of the normal samples. In both hyperplastic polyps and serrated adenomas, MUC2 and MUC5AC mucin expression was consistently and markedly increased. In 50% of the hyperplastic polyps, MUC4 was reduced but in the remaining cases was similar to normal. Loss of MUC4 expression was observed in all serrated adenomas. MUC1 was not increased in the hyperplastic polyps but increased expression was seen in 17 of the serrated adenomas (63%). Similar altered distribution patterns of MUC2, MUC4, and MUC5AC were seen in hyperplastic polyps and serrated adenomas, whereas traditional adenomas showed little change from normal patterns of expression. Although hyperplastic polyps are commonly defined as benign lesions without neoplastic potential, the similar phenotypes of hyperplastic and serrated adenomas and the existence of mixed polyps suggest that these lesions may represent a histogenetic continuum.

Well-differentiated adenocarcinoma mimicking complete-type intestinal metaplasia in the stomach

We describe extremely well-differentiated intestinal-type adenocarcinomas of the stomach which mimic complete-type intestinal metaplasia. It is often difficult to discriminate such neoplastic lesions from inflamed or regenerative changes of intestinal metaplasia histologically. The aim of this study was to elucidate the clinicopathologic features of this unique carcinoma. Eight cases of gastric carcinoma of this type that were invasive beyond the muscularis mucosae were selected for mucin histochemical and immunohistochemical analyses. The carcinomas showed the following features: (1) predominant cells that had differentiated to mature neoplastic cells, with features of small intestinal absorptive cells (complete-type intestinal metaplastic cells), which have sialomucin, MUC2-positive cells, and brush border features detected by CD10 (56C6) staining; (2) neoplastic tubules in the mucosa showing branching, tortuous, anastomosing, and plexiform structures, which were more pathognomonic than the cytological features; (3) lesions distributed predominantly in the middle third of the stomach and surrounded by the fundic mucosa; and (4) zonal distribution of Ki-67-positive proliferative cells like those of intestinal metaplasia in the lower third to half of the cancerous tubules in the mucosa. The lesions consisted mainly of illusory carcinoma; however, there were foci of pathognomonic elements in some areas of the tumors. Several biopsy samplings of the lesion would ensure the histopathologic diagnosis. This unique lesion forms a subgroup of intestinal-type carcinomas of the stomach and is suggested to have a close link with complete-type intestinal metaplasia, previously ignored as a precancerous lesion.

DNA microsatellite instability in hyperplastic polyps, serrated adenomas, and mixed polyps: a mild mutator pathway for colorectal cancer?

AIM

To investigate the distribution of DNA microsatellite instability (MSI) in a series of hyperplastic polyps, serrated adenomas, and mixed polyps of the colorectum.

METHODS

DNA was extracted from samples of 73 colorectal polyps comprising tubular adenomas (23), hyperplastic polyps (21), serrated adenomas (17), and mixed polyps (12). The presence of MSI was investigated at six loci: MYCL, D2S123, F13B, BAT-40, BAT-26, and c-myb T22, using polymerase chain reaction based methodology. MSI cases were classified as MSI-Low (MSI-L) and MSI-High (MSI-H), based on the number of affected loci.

RESULTS

The frequency of MSI increased in tubular adenomas (13%), hyperplastic polyps (29%), serrated adenomas (53%), and mixed polyps (83%) (Wilcoxon rank sum statistic, p < 0.001). Hyperplastic epithelium was present in nine of 12 mixed polyps and showed MSI in eight of these. MSI was mostly MSI-L. MSI-H occurred in two serrated adenomas and three mixed polyps. Clonal relations were demonstrated between hyperplastic and dysplastic epithelium in four of eight informative mixed polyps.

CONCLUSIONS

The findings support the view that hyperplastic polyps may be fundamentally neoplastic rather than hyperplastic. A proportion of hyperplastic polyps may serve as a precursor of a subset (10%) of colorectal cancers showing the MSI-L phenotype, albeit through the intermediate step of serrated dysplasia. This represents a novel and distinct morphogenetic pathway for colorectal cancer.

Advantages of immunostaining over DNA analysis using PCR amplification to detect p53 abnormality in long-term formalin-fixed tissues of human colorectal carcinomas

To study the appropriate period for formalin fixation in order to detect p53 abnormalities in formalin-fixed tissue, we used seven surgically resected human colorectal cancer specimens. The immunohistochemical reactivity of p53 immunostaining and amplification of DNA by polymerase chain reaction (PCR) of the p53 gene were compared after various periods of 10% formalin fixation (1 day, and 1, 2, 4, and 8 weeks). For comparative immunostaining, we used the monoclonal antibody Ki-67 (MIB-1), and for comparative polymerase chain reaction (PCR), K-ras at codon 12 was amplified. Immunostaining was performed by the streptavidin-biotin method with microwave retrieval, and PCR amplifications were performed by the nested PCR method. p53 and Ki-67 immunoreactivity did not change essentially for up to 2 weeks and 1 week, respectively, of formalin fixation. PCR amplification for p53 at exon 8 and K-ras at codon 12 was successful until 1 day and 2 weeks, respectively, of formalin-fixation for the specimens of all seven cases. Thereafter, the amplification tended to worsen as the fixation time lengthened. Further, the DNA was more successfully amplified in the second PCR than in the first. These results suggest that to detect p53 abnormality in specimens that have been formalin-fixed for long periods, immunohistochemical staining may have advantages over DNA analysis with PCR amplification.

[Genetic alterations in gallbladder carcinoma: a review]

Earlier evidence suggests that gallbladder carcinoma (GBC) has three carcinogenic pathways; de novo development; adenoma-carcinoma sequence; and hyperplasia-carcinoma sequence associated with an anomalous arrangement of the pancreaticobiliary duct (AAPBD). We review gene abnormalities in GBC reported to date. p53 mutation and its protein overexpression are frequently observed in de novo carcinoma and GBC with AAPBD, but never found in carcinoma with adenoma. The incidence of K-ras codon 12 mutation in GBCs with AAPBD is significantly higher than that in the other types. Mutation of K-ras is never detected in carcinoma with adenoma. These findings suggest that diverse genetic pathways may exist in gallbladder carcinogenesis and reflect morphologic variations.

Infrequent K-ras codon 12 mutation in serrated adenomas of human colorectum

BACKGROUND

Serrated adenoma is a new morphological subtype of colorectal adenoma. The lesion provides a distinct morphological route to carcinoma, but the underlying genetic changes have not yet been investigated.

AIMS

To determine the frequency of K-ras mutation in serrated adenoma.

METHODS

The frequency of K-ras codon 12 point mutation in 20 serrated adenomas, five atypical hyperplastic polyps, and 58 sporadic polypoid adenomas was investigated by nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods.

RESULTS

Although most of the serrated adenomas were large (average size 11.4 mm) and polypoid, K-ras codon 12 point mutation was detected in only one of the 20 (5%), which is a significantly lower frequency than that in sporadic polypoid adenomas (18/60; 30%) (p = 0.017). No mutation was detected in the atypical hyperplastic polyps. Three of 20 (15%) serrated adenomas contained a focus of carcinoma in situ, indicating their malignant potential and the existence of a serrated adenoma-carcinoma sequence, but no mutation was detected in the foci of carcinoma in situ.

CONCLUSIONS

K-ras mutation is uncommon in serrated adenomas, indicating a different spectrum of genetic alterations in these lesions from those in typical polypoid sporadic adenomas. This subtype of colorectal adenoma represents a new genetic pathway in the histogenesis of colorectal carcinoma.

Mutations of p53 in gallbladder carcinomas in high-incidence areas of Japan and Chile

Gallbladder adenocarcinomas from patients in two high-prevalence areas, Niigata (Japan) and Santiago (Chile), were analyzed for acquired mutations in exons 5-8 of the p53 tumor suppressor gene, and the characteristics of p53 alterations in the two groups were compared. Of 42 tumors, 22 (52.4%) harbored 25 alterations identified by PCR amplification and direct sequencing (13 of 22 tumors from Niigata and 12 of 20 tumors from Santiago). All alterations were single base pair substitutions, 20 (80%) leading to an amino acid substitution or a chain-termination signal, and 5 (20%) were silent. Immunohistochemically, 55 of 84 cases (65.5%) showed overexpression of p53 protein, with no significant difference in frequency between the two areas. Missense mutations correlated highly with overexpression of the p53 protein (93.4%). Mutations of p53 occurred in all four exons examined, most commonly in exon 5, but in no particular "hot spot." In base-change spectra, all 12 mutations from Santiago showed transitions, with 4 arising at the CpG dinucleotide (33.3%). In contrast, no such transition was found at CpG sites in Niigata, and 4 of 13 mutations (30.8%) were transversions. The data indicated that p53 mutations are highly important in carcinogenesis in the gallbladder. In addition, the difference in p53 mutational spectra in Niigata and Santiago indicate a likely regional difference in mutagenesis.

Heterogeneity of p53 mutational status in esophageal squamous cell carcinoma

In esophageal squamous cell carcinoma, p53 gene mutations have been analyzed for inter- or intra-patient heterogeneity but only a few studies have investigated intratumoral heterogeneity. We investigated this question within individual esophageal cancers, and also in their lymph-node metastases in 8 cases. Analyzing the p53 gene sequence by direct sequencing of polymerase chain reaction products, we found heterogeneity for p53 mutations in the pre-invasive area in 3 esophageal cancers. In all areas sampled in the invasive portion of each cancer, the p53 mutational status was identical in a given tumor. In heterogeneous tumors, the invasive area showed one of the p53 mutations found in the pre-invasive area. In nodal metastases, the p53 mutation was identical to that in the invasive area of each primary tumor. These data suggest that the timing of p53 alteration is not as early as might have been expected, indicating that, in regard to p53 gene alteration, some esophageal cancers are composed of various subclones in the pre-invasive stage with invasiveness developing in one of them, which becomes predominant through clonal selection.

Determination of pancreatic ductal carcinoma histogenesis by analysis of mucous quality and K-ras mutation

BACKGROUND

The authors sought to elucidate the histogenesis of pancreatic ductal carcinoma by correlating K-ras mutation with mucus type in normal epithelium, mucous cell hyperplasia (MCH), and carcinoma.

METHODS

Seventy-four solid-type carcinomas (SCs), 23 ductectatic-type carcinomas (DCs), and specimens of 24 normal pancreata were studied. By histochemical staining, normal duct epithelia, areas of MCH, and carcinomas were classified as having sulfo-type or sialo-type mucus. Foci from normal, DC, SC, sulfo-type, or sialo-type specimens were assessed for K-ras mutation at codon 12 by nested polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

Of the SCs, 9 were sulfo-type and 65 were sialo-type; all DC specimens were sialo-type, and all normal epithelia were sulfo-type. All foci of sulfo-type, nonneoplastic epithelia were negative for K-ras mutation. In contrast, 124 of 313 sialo-type MCH foci (40%) had a K-ras mutation. Of 74 SCs, only 3 of 9 sulfo-type tumors (33%) were positive for the mutation. Sixty of 65 sialo-type SCs (92%) had a K-ras mutation, whereas 15 of 23 sialo-type DCs (65%) had a mutation. K-ras mutant carcinomas (including both SCs and DCs) were associated with K-ras mutant MCH in 109 of 198 MCHs (55%), whereas carcinomas without a K-ras mutation had mutations in 6 of 68 MCHs (9%). MCH in normal pancreata revealed K-ras mutations in 9 of 51 foci (18%). In addition, in K-ras mutant carcinomas, frequency of K-ras mutation in MCH increased from 27% (11 of 41 foci) of nonpapillary MCHs to 62% (98 of 157 foci) of papillary MCHs; but in K-ras wild-type carcinoma, the mutation rate in MCH was unchanged from 12% (3 of 26 foci) to 7% (3 of 42 foci) in nonpapillary and papillary foci, respectively.

CONCLUSIONS

These results suggest a strong relationship between the risk of pancreatic carcinoma and the presence of combinations of K-ras gene mutation, papillary growth, and expression of sialomucin in foci of MCH.

Immunoperoxidase staining for cytokeratins 8 and 18 is very sensitive for detection of occult node metastasis of colorectal cancer: a comparison with genetic analysis of K-ras

AIMS

Recent reports suggest that genetic examination of K-ras or p53 mutation is more sensitive for the detection of occult lymph node metastasis in colorectal carcinomas than conventional examination by haematoxylin and eosin (H & E) staining or immunohistochemistry for gene products. The aim of this study was, first, to define the microscopic characteristics of metastatic cancer cells in lymph nodes stained by the anti-cytokeratin antibody CAM5.2 for cytokeratins 8 and 18, and, second, to compare the detection rate of occult lymph node metastasis for immunohistochemical vs genetic methods.

METHODS AND RESULTS

K-ras mutations were first examined in primary tumours of seven cases which showed distant metastasis or local recurrence within 5 years of the initial surgery in spite of the original reporting of no lymph node metastasis by routine H & E staining. K-ras mutations were positive in three cases in primary tumours and lymph nodes, and the remaining four primary tumours were negative for p53 mutation as well as K-ras mutation. Therefore, genetic analysis of occult lymph node metastasis was uninformative, but occult metastasis was detected by cytokeratin staining in two of these four cases. Comparative study of cytokeratin-positive cells was performed on each of the 43 lymph nodes from three cases with K-ras mutations. Cancer cells were detected in 28 of the 43 lymph nodes (65.1%) by cytokeratin staining and in 10 of the 43 corresponding lymph nodes (23.3%) by genetic analysis. Artefactual contamination by cancer cells was present in eight of the 28 cytokeratin positive lymph nodes, and three of the eight nodes were genetically positive.

CONCLUSIONS

This study suggests that cytokeratin immunohistochemistry is more sensitive and specific for the detection of occult lymph node metastasis than genetic diagnosis by K-ras mutation in cases with genetic alterations as well as in cases without them.

Determination of pancreatic ductal carcinoma histogenesis by analysis of mucous quality and K-ras mutation

BACKGROUND

The authors sought to elucidate the histogenesis of pancreatic ductal carcinoma by correlating K-ras mutation with mucus type in normal epithelium, mucous cell hyperplasia (MCH), and carcinoma.

METHODS

Seventy-four solid-type carcinomas (SCs), 23 ductectatic-type carcinomas (DCs), and specimens of 24 normal pancreata were studied. By histochemical staining, normal duct epithelia, areas of MCH, and carcinomas were classified as having sulfo-type or sialo-type mucus. Foci from normal, DC, SC, sulfo-type, or sialo-type specimens were assessed for K-ras mutation at codon 12 by nested polymerase chain reaction and restriction fragment length polymorphism.

RESULTS

Of the SCs, 9 were sulfo-type and 65 were sialo-type; all DC specimens were sialo-type, and all normal epithelia were sulfo-type. All foci of sulfo-type, nonneoplastic epithelia were negative for K-ras mutation. In contrast, 124 of 313 sialo-type MCH foci (40%) had a K-ras mutation. Of 74 SCs, only 3 of 9 sulfo-type tumors (33%) were positive for the mutation. Sixty of 65 sialo-type SCs (92%) had a K-ras mutation, whereas 15 of 23 sialo-type DCs (65%) had a mutation. K-ras mutant carcinomas (including both SCs and DCs) were associated with K-ras mutant MCH in 109 of 198 MCHs (55%), whereas carcinomas without a K-ras mutation had mutations in 6 of 68 MCHs (9%). MCH in normal pancreata revealed K-ras mutations in 9 of 51 foci (18%). In addition, in K-ras mutant carcinomas, frequency of K-ras mutation in MCH increased from 27% (11 of 41 foci) of nonpapillary MCHs to 62% (98 of 157 foci) of papillary MCHs; but in K-ras wild-type carcinoma, the mutation rate in MCH was unchanged from 12% (3 of 26 foci) to 7% (3 of 42 foci) in nonpapillary and papillary foci, respectively.

CONCLUSIONS

These results suggest a strong relationship between the risk of pancreatic carcinoma and the presence of combinations of K-ras gene mutation, papillary growth, and expression of sialomucin in foci of MCH.

[The autopsy case of traumatic carotid artery dissection]

The results of an autopsy of a 78-year-old female patient with an occluded of the right internal carotid artery after a traffic accident are reported. She presented with consciousness disturbance, right conjugate deviation, left hemiparesis and left pathological reflex. Evidence of right skull and clavicular fractures seemed to suggest that severe hyperextension of her neck associated with contralateral lateral flexion had stretched her carotid artery. Although she was treated with antiplatelet therapy, her cerebral swelling due to right global infarction progressed and she died due to bilateral cerebral herniation three days after injury. The autopsy disclosed right dissecting carotid artery occlusion and subadventitial dissection was revealed histologically. When a hematoma dissect the media and adventitia of the carotid artery wall, the outer wall weakens and may dilate without narrowing the lumen of the carotid artery. In this case, the vessel occlusion was considered to be due to a primary intramural hematoma which developed and subsequently ruptured through the intima into the vessel lumen. Early diagnosis and treatment are necessary for improving the prognosis of this disease entity. A patient with poor colateral flow, such as in this case, will show a rapid progression of cerebral infarction. It is best to consider surgical treatment in this case if the other traumatic lesions are able to tolerate surgery.

Alteration of p53 clonality accompanying colorectal cancer progression

The aim of this study was to clarify whether or not the status of gene alteration is heterogeneous in intramucosal carcinoma and homogeneous within invasive carcinoma. We selected 10 colorectal carcinoma cases (1 mucosal, 5 submucosal and 4 advanced carcinomas including 2 cases with lymph node metastasis) and analyzed the p53 gene sequence. Six colorectal cancers in this study showed heterogeneity in p53 mutations in cells from the intramucosal part. In the invasive part of a carcinoma, p53 mutation status was homogeneous intratumorally in all cases. These data indicate that, in regard to p53 gene alterations, colorectal cancers can be composed of various subclones when limited to the mucosa, but clonal selection occurs when one of these subclones commences invasion to the submucosa, generating a monoclonal invasive carcinoma.

Occult lymph node metastases detected by cytokeratin immunohistochemistry predict recurrence in "node-negative" colorectal cancer

There is controversy about the prognostic significance of occult lymph node metastases detected by immunohistochemistry with the anti-cytokeratin antibody CAM 5.2. The aim of this study was to characterize occult lymph node metastases in colorectal carcinomas that might be associated with a higher risk of recurrence. Three hundred fifty-eight lymph nodes from 10 recurrent and 9 nonrecurrent cases of colorectal carcinoma were examined. All these patients had been reported originally as having no lymph node metastases by routine hematoxylin and eosin staining. Three 10-micron sections or ten 3-micron sections (30-micron total thickness) from each lymph node were stained with CAM 5.2 and examined for the presence of occult lymph node metastases. Occult metastases were detected in 67 of 175 lymph nodes from the recurrent cases, and in 23 of 183 lymph nodes from the nonrecurrent cases. The frequency of positive nodes was significantly higher in the recurrent cases. The recurrent cases had metastases in nodes more distant from the main tumor than did the nonrecurrent cases. Detection of occult lymph node metastases with cytokeratin immunohistochemistry may make it possible to identify patients with a higher risk of recurrence after the removal of a primary colorectal tumor.