Genomic changes in endometrial polyps associated with tamoxifen show no evidence for its action as an external carcinogen

Eighty-eight endometrial specimens from 36 postmenopausal breast cancer patients treated with tamoxifen were investigated cytogenetically and molecularly using fluorescence in situ hybridization with appropriate probes for the HMGIC and HMGIY genes. Twenty control specimens, 10 endometrial polyps, and 10 endometrial biopsy specimens were investigated in the same way. Of the 88 specimens, 44 were from endometrial polyps; 3 were from endocervical polyps; 7 were from cystic endometrium; 30 were from normal or atrophic endometrium, normal endocervix, or myometrium; and 4 were from endometrial carcinomas. Chromosome investigation of the endometrial polyps showed the nature of the chromosome changes in tamoxifen-induced polyps to be the same as that in the controls and in sporadic endometrial polyps described in the literature. HMGIC and HMGIY gene rearrangements in both groups were identical as shown by fluorescence in situ hybridization, which also allowed for the detection of seven hidden paracentric inversions involving 12q15, one of which occurred in a cystic endometrium. The carcinomas did not exhibit any of these changes. Because abnormal expression of HMGIC or HMGIY as a consequence of structural chromosome changes in 12q15 or 6p21, respectively, is invariably associated with benign neoplasia, tamoxifen-associated endometrial polyps are unlikely to undergo further malignant transformation, and a mode of action of tamoxifen as an external carcinogen is unlikely.

Diagnosis of hereditary non-polyposis colorectal cancer

The term hereditary non-polyposis colorectal cancer (HNPCC) was introduced initially to encompass autosomal dominant syndromes predisposing to colorectal cancer other than the polyposes. The term is a poor descriptor and is often applied to families on the basis of inadequate information. It is suggested that 'hereditary mismatch repair deficiency syndrome' (HMRDS) should replace the term HNPCC for describing the specific autosomal dominant condition which predisposes to cancer displaying the mutator phenotype. Population-based studies have shown that HMRDS probably accounts for no more than 2% of bowel cancer. A working diagnosis of HMRDS can be made on the basis of clinical, pathological and molecular characteristics. The histopathologist has an important role to play in the recognition and diagnosis of HMRDS. The characteristic morphology of colorectal cancer in HMRDS is reviewed and the diagnostic utility of 'field changes' and adenomas is discussed critically.

Amplification and expression of the HMGIC gene in a benign endometrial polyp

In a totally benign endometrial polyp, double minute chromosomes were shown to contain an amplified and apparently nonrearranged HMGIC gene, expressed in the tumor cells, suggesting amplification of HMGIC through double minute chromosome formation as another hitherto unreported mechanism associated with the development of some mesenchymal tumors.

A survey of phenotypic features in juvenile polyposis

Solitary juvenile polyps are quite frequent in children, but juvenile polyposis (JP) is a rare autosomal dominant trait characterised by the occurrence of numerous polyps in the gastrointestinal tract. Extracolonic phenotypic abnormalities are well documented in patients with familial adenomatous polyposis and Peutz-Jeghers syndrome and can allow a clinical diagnosis to be made before the bowel pathology becomes available. Though described, characteristic extracolonic abnormalities have not been clearly defined in juvenile polyposis. We sought to determine whether there are consistent extracolonic phenotypic abnormalities in JP patients and how frequently this would allow diagnosis of one of the genetic syndromes known to be associated with juvenile polyposis. Twenty-two JP patients underwent clinical examination and data from one patient were obtained from case notes. Those consenting to further investigations had x rays of the skull, chest, and hands and an echocardiogram if clinically indicated. Significant extracolonic phenotypic abnormalities were present in 18 patients (14 male and four female), and included dermatological (13), skeletal (16), neurological (5), cardiopulmonary (4), gastrointestinal (3), genitourinary (4), and ocular (1) features. In five patients the diagnosis of a genetic syndrome was possible: two had Bannayan-Riley-Ruvalcaba syndrome, two had Gorlin syndrome, and one had hereditary haemorrhagic telangiectasia (HHT, also known as Osler-Rendu-Weber syndrome). Other patients had some features of these conditions and of Cowden and Simpson-Golabi-Behmel syndromes, but these were not sufficient to allow a definitive diagnosis.

Exclusion of PTEN and 10q22-24 as the susceptibility locus for juvenile polyposis syndrome

Juvenile polyposis syndrome (JPS; MIM 174900) is an autosomal dominant condition with incomplete penetrance characterized by hamartomatous polyps of the gastrointestinal tract and a risk of gastrointestinal cancer. Gastrointestinal hamartomatous polyps are also present in Cowden syndrome (CS; MIM 158350) and Bannayan-Zonana syndrome (BZS; also called Ruvalcaba-Myhre-Smith syndrome; MIM 153480). The susceptibility locus for both CS and BZS has recently been identified as the novel tumor suppressor gene PTEN, encoding a dual specificity phosphatase, located at 10q23.3. A putative JPS locus, JP1, which most likely functions as a tumor suppressor, had previously been mapped to 10q22-24 in both familial and sporadic juvenile polyps. Given the shared clinical features of gastrointestinal hamartomatous polyps among the three syndromes and the coincident mapping of JP1 to the region of PTEN, we sought to determine whether JPS was allelic to CS and BZS by mutation analysis of PTEN and linkage approaches. Microsatellite markers spanning the CS/BZS locus (D10S219, D10S551, D10S579, and D10S541) were used to compute multipoint lod scores in eight informative families with JPS. Lod scores of < -2.0 were generated for the entire region, thus excluding PTEN and any genes within the flanking 20-cM interval as candidate loci for familial JPS under our statistical models. In addition, analysis of PTEN using a combination of denaturing gradient gel electrophoresis and direct sequencing was unable to identify a germline mutation in 14 families with JPS and 11 sporadic cases. Therefore, at least a proportion of JPS cases are not caused by germline PTEN alteration or by an alternative locus at 10q22-24.

Lhermitte-Duclos disease associated with Cowden's disease--case report

A 49-year-old Japanese male with Lhermitte-Duclos disease subsequently developed a very rare association with Cowden's disease. Partial tumor removal established the diagnosis of Lhermitte-Duclos disease. Follow-up examinations discovered the presence of Cowden's disease. Long-term follow-up of patients with Lhermitte-Duclos disease is essential to identify signs of Cowden's disease, which carries the risk of developing malignancy.

Juvenile polyposis of the stomach: clinicopathological features and its malignant potential

AIMS

To clarify a clinical entity of juvenile polyposis of the stomach compared with generalised juvenile gastrointestinal polyposis.

METHODS

The clinicopathological features of juvenile polyposis dominantly involving the stomach at initial presentation were reviewed in 12 patients (three new patients and nine from the literature). These were compared with 29 cases of generalised juvenile gastrointestinal polyposis.

RESULTS

There were three men and nine women with juvenile polyposis of the stomach, aged 10-63 years. Hypoproteinaemia was present in nine patients, anaemia in seven, and a family history of intestinal polyposis in seven. No patient presented with a congenital abnormality. During the observation period, two patients developed colonic juvenile polyps. Gastric polyps invariably affected the antrum and extended to the fundus, eventually becoming more numerous, larger, and more pedunculated. Ten patients required gastrectomy for associated malignancy or uncontrolled protein losing gastropathy. Histological examinations of the resected specimens demonstrated neoplastic tissue arising from juvenile polyps in four of the 12 patients. Atypism in these mixed polyps varied from adenoma to well or moderately differentiated adenocarcinoma.

CONCLUSIONS

Juvenile polyposis of the stomach has malignant potential, and may be a separate entity from generalised juvenile gastrointestinal polyposis.

Low epithelial cell proliferation and absence of oncoprotein expression in juvenile polyposis of the stomach, with or without tumors

OBJECTIVES

To assess cell proliferation and analyze oncogenetic abnormalities in cases of juvenile polyposis of the stomach (JPs), with or without coexisting tumors.

METHODS

The Ki-67 labeling indices (KLI) were compared for juvenile polyps and coexisting tumors in three cases of JPs along with values for gastritis, foveolar epithelial hyperplastic polyps, adenomas, and carcinomas. Expression of p53, Bcl-2, and c-ErbB-2 in tumors was examined immunohistochemically, and a search for c-Ki-ras mutations was made by DNA direct sequencing.

RESULTS

The KLI for JPs did not significantly differ between cases, being consistently lower than the values for both hyperplastic polyps and gastritis. The KLI for the papillary tumors and a signet ring cell carcinoma found in association with JPs tended to be lower than those for their conventional counterparts. P53, but not Bcl-2 and c-ErbB-2, was focally expressed in the papillary tumors, whereas all three were absent in the signet ring cell carcinoma, in the JPs. No c-Ki-ras mutations were detected in the papillary tumors.

CONCLUSIONS

The cell proliferation of JPs is relatively low and the polyps can be considered hamartomatous. However, neoplastic change clearly can occur in association with a relative increase in proliferative activity being observed in coexisting tumors. Low cellular proliferative activity and absence of oncogenetic abnormalities in tumors of JPs, compared with their conventional counterpart tumors, suggest that pathways of tumorigenesis and genetic alteration in JPs may be different from those in their conventional counterparts.

High frequency of K-ras mutations in human colorectal hyperplastic polyps

BACKGROUND

Hyperplastic polyps are common benign colorectal polyps, and are thought to have little association with malignant tumours in the colorectum. However, several reports suggest that some hyperplastic polyps may develop into colorectal neoplasms.

AIM

To clarify genetic alterations in colorectal hyperplastic polyps.

METHODS

Twenty eight colorectal polyps having serrated components were resected from patients endoscopically. The K-ras gene mutations in codons 12 and 13 were analysed by PCR-RFLP. Intranuclear p53 protein was immunostained by the avidin-biotin complex method.

RESULTS

A mutation of the K-ras gene was detected in nine (47%) of 19 hyperplastic polyps, and five (56%) of nine adenomas. p53 protein nuclear accumulation was detected immunohistochemically in two (22%) of nine adenomas, but not in any of the hyperplastic polyps.

CONCLUSION

Some hyperplastic polyps may be true neoplastic lesions, and could be precursors of malignant neoplasia.

A juvenile polyposis tumor suppressor locus at 10q22 is deleted from nonepithelial cells in the lamina propria

BACKGROUND & AIMS

Juvenile polyps are characterized by an abundant lamina propria that lacks smooth muscle and may contain cystically dilated glands, with epithelium that seems normal and is nondysplastic. Rarely, an autosomal dominant inheritance pattern occurs. The aim of this study was to test the hypothesis that the genetic defect in both sporadic juvenile polyps and hereditary juvenile polyposis involves loss of function for a tumor suppressor gene.

METHODS

Allelic losses were detected by comparing normal DNA with tumor DNA from a series of 47 juvenile polyps from 16 patients using polymerase chain reaction amplification of microsatellite markers and fluorescent in situ hybridization (FISH).

RESULTS

Somatic deletions at 10q22 were detected in 39 of 47 juvenile polyps (83%) from 16 unrelated patients with either hereditary or sporadic juvenile polyps, and the minimum overlap localized juvenile polyposis coli to the 3-cM interval D10S219-D10S1696. Fluorescent in situ hybridization shows that the cells affected by deletion mutation reside exclusively in the lamina propria, not in the epithelium.

CONCLUSIONS

The location of a novel tumor suppressor gene on chromosome 10 that is affected by deletion mutation in the majority of juvenile polyps was mapped. Unlike adenomas and carcinomas of the colonic epithelium, juvenile polyps originate in the lamina propria.

The expression of p185(HER-2/neu) correlates with the stage of disease and survival in colorectal cancer

BACKGROUND & AIMS

HER-2/neu oncogene encodes a transmembrane tyrosine kinase receptor that is amplified and/or overexpressed predominantly in adenocarcinomas. This phenomenon has been most intensively studied in breast carcinoma where its amplification and overexpression correlate with the overall course of disease and poor prognosis. This study was designed to investigate HER-2/neu gene expression in benign and malignant colorectal lesions and to evaluate its prognostic importance in colorectal cancer.

METHODS

Two hundred twenty-one samples of normal colon, benign lesions, and colorectal adenocarcinomas were studied for expression of HER-2/neu oncoprotein. Immunohistochemical staining of formalin-fixed, paraffin-embedded tissue sections of primary tumor and lymph nodes was performed. Immunoprecipitation followed by Western blotting of freshly frozen samples of the same tumors were also performed.

RESULTS

Normal colon mucosa, benign lesions, and adenocarcinomas clearly differed in the expression levels and histological distribution of p185(HER-2/neu). Normal mucosa was mostly negative, but significant number of benign lesions and adenocarcinomas overexpressed HER-2/neu protein. Adenocarcinomas were significantly more positive than benign lesions. The results show significant correlation with the epithelial abnormality degree and clinical parameters including Dukes' classification and relapse-free and postoperative survival period.

CONCLUSIONS

The p185(HER-2/neu) rate expression could serve as an independent prognostic factor in patients with p185(HER-2/neu)-positive colorectal malignancies.

p53 protein expression in benign lesions of the upper respiratory tract

OBJECTIVE

p53 is a tumor suppressor gene that is lost or mutated in most forms of human malignancy. There are, however, very few studies evaluating p53 expression in normal epithelium or benign lesions.

DESIGN

We screened for p53 protein expression in a variety of benign epithelial lesions of upper respiratory tract using monoclonal antibody DO-1 on paraffin-embedded material.

SUBJECTS

We studied a total of 109 cases: 16 cases of juvenile and 36 cases of adult laryngeal papillomatosis, 10 cases each of laryngeal nodules and laryngeal polyps, 17 cases of inverted papilloma, and 20 cases of nasal polyps.

RESULTS

Nuclear immunoreactivity for p53 protein was demonstrated in 14 (88%) of 16 cases of juvenile laryngeal papillomatosis, 33 (92%) of 36 cases of adult laryngeal papillomatosis, 4 (40%) of 10 cases of laryngeal nodules, 8 (80%) of 10 cases of laryngeal polyps, 7 (41%) of 17 cases of inverted papilloma, and 2 (10%) of 20 cases of nasal polyps. These results pertained only to the basal epithelial layer in all cases of laryngeal nodules, laryngeal polyps, and nasal polyps. Intermediate layer cells were also positive for p53 in the majority of the cases of both juvenile (69%) and adult (75%) laryngeal papillomatosis and in a minority of the cases of inverted papilloma (18%).

CONCLUSIONS

Overexpression of p53 protein is commonly demonstrable in benign epithelial lesions of the upper respiratory tract. This observation suggests that p53 protein accumulation may occur in the absence of mutation of the p53 gene and may correlate with epithelial proliferative activity.

Multiple hyperplastic polyps in the stomach: evidence for clonality and neoplastic potential

The origin and neoplastic potential of gastric epithelial polyps remains an area of great interest, and treatment choices are a topic of controversy. This report describes a patient diagnosed with three concurrent hyperplastic gastric polyps that were studied for genetic alterations. The polyps were investigated for alterations in the K-ras oncogene and the p53 tumor suppressor gene and for p21WAF1/Cip1 and MDM2 protein overexpression. In addition, loss of heterozygosity at several loci that are frequently involved in human cancer was analyzed, microsatellite instability, a hallmark of the "mutator" phenotype, was determined, and Epstein-Barr virus infection was investigated. All separate areas from the three independent polyps harbored the same activating point mutation in codon 12 of the K-ras oncogene, indicating a clonal origin. DNA sequence alterations in p53 were not found, although high p53 protein levels could be shown by immunohistochemistry in areas of carcinoma within the largest polyp. No alterations in any of the other molecular markers were observed. The results strongly favor a clonal origin of the three independent gastric polyps and support the notion that these hyperplastic polyps may carry a risk for malignancy.

A novel deletion within exon 6 of TP53 in a family with Li-Fraumeni-like syndrome, and LOH in a benign lesion from a mutation carrier

We report here a family with some of the characteristics of Li-Fraumeni syndrome (Li-Fraumeni-like) in which there is a 2 base pair deletion within exon 6 of TP53 in two affected individuals. Of particular interest in this family is a study of loss of heterozygosity (LOH) of the TP53 gene, and the finding that there is LOH in all cancers available for study from mutation carriers, and additionally from a benign endometrial polyp from one of those patients. Two other family members, one with a rectal carcinoma aged 55, the other with two separate benign lesions under the age of 45, were both wild-type for the TP53 mutation.

An endometrial polyp with a rearrangement of HMGI-C underlying a complex cytogenetic rearrangement involving chromosomes 2 and 12

Cytogenetic studies of an endometrial polyp of an 82-year-old patient revealed a karyotype 46,XX,der(2)inv(2)(p25q21)ins(2;12)(p25;q13q14)t(2;12)(q21; q15),der(12)del(12)(q13q14)del(12)(q15). By fluorescence in situ hybridization (FISH) we found the chromosome 12 translocation breakpoint to be mapping within the third intron of the HMGI-C gene also harboring the breakpoints of translocations involving 12q15 seen in uterine leiomyomas, lipomas, pleomorphic adenomas, and pulmonary chondroid hamartomas.

Positive identification in situ of mRNA expression of IL-6, and IL-12, and the chemotactic cytokine RANTES in patients with chronic sinusitis and polypoid disease. Clinical relevance and relation to allergy

Interleukins 6 (IL-6) and 12 (IL-12), and the chemoattractant chemokine RANTES were studied in ethmoidal mucosa, using reverse transcriptase polymerase chain reaction. The 49 patients had chronic sinusitis or nasal/paranasal polyposis, and some also allergy. To the best of our knowledge, this is the first study that demonstrates RANTES and IL-12 on mRNA level in human sinonasal mucosa in situ. mRNA for IL-6, IL-12 and RANTES were detected in 2, 8 and 6 patients with chronic sinusitis, respectively, and in mucosa from patients with polyposis a positive expression was observed in 4, 14 and 10 cases. There were no statistically significant differences. Analysing the entire group of 49 patients, disregarding type of mucosal disease, the number of patients with positive RANTES was significantly higher than that for IL-6. Similarly, IL-12 positivity was more frequently expressed than IL-6. mRNA for IL-6 was expressed in only 2 of the allergic patients. The cytokine production studied thus seems to be unrelated to the clinically defined entities. There is thus a local production in human diseased sinonasal mucosa of RANTES, as well as of IL-6 and IL-12. The local production of RANTES is an important prerequisite for recruitment and migration of inflammatory cells into the tissue. IL-12 is a co-stimulator of antigen-specific responses of established T helper 1 (Th1) clones, and regulates the responsiveness of the clones to a number of T cell growth factors. The study supports a shift towards Th1 cells in these disease entities.

Rearrangements of the high mobility group protein family genes and the molecular genetic origin of uterine leiomyomas and endometrial polyps

The results of cytogenetic studies of uterine leiomyomas have revealed that approximately 50% of these tumours are characterized by clonal chromosomal alterations. These karyotypic deviations are dominated by rearrangements involving a particular part of chromosome 12, i.e. region 12q13-15. We recently showed that the multiple aberration region on chromosome 12q15 harbours recurrent breakpoints frequently found in a variety of benign solid tumours. Within this region a gene encoding for a member of the so called high mobility group family proteins (HMG) was mapped. Further investigation revealed that this gene i.e. HMGI-C is often truncated by the chromosomal aberrations and fused to ectopic DNA sequences leading to fusion genes. Therefore, the results suggest a causal relationship between mutations of the HMGI-C gene and the development of uterine leiomyomas. Apparently identical mutations have been found also in endometrial polyps. Furthermore, there is an obvious coincidence between the chromosomal assignment of other members of the HMG family and the breakpoints of other non-random chromosome abnormalities seen in uterine leiomyomas.

Molecular evidence links lymphomatous polyposis of the gastrointestinal tract with mantle cell lymphoma

Lymphomatous polyposis (LP) is a subtype of non-Hodgkin's lymphoma manifested by numerous polyps affecting long segments of the gastrointestinal tract. The malignant cells of LP often share morphological and immunophenotypic similarity with cells of nodal-based mantle cell lymphoma. Recent genetic studies have shown that mantle cell lymphomas frequently possess a characteristic translocation of the JH/bcl-1 loci. In this study, polymerase chain reaction (PCR) and Southern blot analysis were used to show the presence of JH/bcl-1 translocation in a typical case of LP of the gastrointestinal tract. This provides strong molecular evidence for a biologic link between LP and mantle cell lymphoma. The findings also imply that detection of this translocation may be useful in the diagnosis of morphologically equivocal gastrointestinal biopsy specimens.

Four cytogenetic subgroups can be identified in endometrial polyps

We have cytogenetically investigated a total of 33 simple benign endometrial polyps, 7 of which have been reported previously. Clonal chromosome rearrangements are found in 19 of 33 lesions (57%). Three major cytogenetically abnormal subgroups can be distinguished: (a) those with rearrangements in the 6p21-p22 region; (b) those with rearrangements of the 12q13-15 region; (c) those with rearrangements of the 7q22 region. A normal karyotype is found in a fourth subgroup. Recombinations of the 6p21-22 region with 2q35 and 10q22, as well as rearrangements of 7q22, have not been described before. It can be concluded that endometrial polyps, like several other types of benign mesenchymal tumors, present several cytogenetically different subgroups despite a seemingly identical clinical and morphological appearance. It is mandatory, therefore, to look for a common denominator of these tumors at the molecular level.

Juvenile polyposis

Juvenile polyposis is an uncommon condition characterized by the development of multiple juvenile polyps, predominantly in the colon but also in the rest of the gastrointestinal tract. The condition usually presents in childhood; only 15 per cent of patients present as adults. The rarer and often fatal form, namely, juvenile polyposis of infancy, is typified by diarrhoea, protein-losing enteropathy, bleeding and rectal prolapse. The more common form of juvenile polyposis (affecting the colon, stomach and small bowel) occurs in the first or second decade with rectal bleeding and anaemia. A family history of the condition is found in 20-50 per cent of patients with apparently an autosomal dominant trait. The gene for juvenile polyposis has not yet been identified. Epithelial dysplasia is common and the cumulative risk of colorectal cancer is > 50 per cent. Various extracolonic abnormalities may also occur. Most patients are treated surgically for colonic polyps, although endoscopic polypectomy is also an option. The rest of the gastrointestinal tract should be screened as should asymptomatic first-degree relatives.

Endometrial polyps with predominant stromal component are characterized by a t(6;14)(p21;q24) translocation

Cytogenetic investigation of endometrial polyps revealed the presence of a t(6;14)(p21;q24) as the sole abnormality in three cases. All tumors showed a histopathological pattern of predominant stromal hyperplasia with scarce representation of glandular elements, suggesting that a cytogenetic subgroup characterized by the t(6;14) translocation can be associated with endometrial polyps with a preponderant component of mesenchymal origin.

Nonrandom chromosomal abnormalities in lymphocyte cultures of individuals with colorectal polyps and of asymptomatic relatives of patients with colorectal cancer or polyps

We studied chromosomal alterations in the peripheral blood lymphocytes of 10 individuals with colorectal polyps and 10 asymptomatic first-degree relatives of patients with colon cancer or colorectal polyps. The analysis was performed on T-lymphocytes using short term blood cultures and on B-lymphocytes by establishing lymphoblastoid cell lines by Epstein-Barr virus transformation. Chromosomal changes were not common in T- and B-lymphocytes. Chromosomes 1 and 5 were most frequently involved in numerical or structural changes in the patients with polyps as well as in the asymptomatic relatives. These alterations were observed in either the T-lymphocytes or the B-lymphocytes but rarely in both, thus accentuating the importance of studying both the cultures concurrently. Chromosome 5, which is known to play an important role in the development of adenomatous polyps, was found to be involved in 6 (60%) of 10 patients with polyps and 4 (40%) of 10 asymptomatic relatives. These findings show that lymphocytic chromosomal analysis can aid in identifying individuals who are genetically susceptible and are at a higher risk of developing colorectal cancer. Because lymphocytic chromosomal analysis is relatively simple and inexpensive, we expect that it will be very useful in screening asymptomatic individuals who are at a higher risk due to inherited or environmental factors.

Hyperplastic polyposis and diffuse carcinoma of the stomach. A study of a family

BACKGROUND

The authors previously described a large pedigree with familial gastric polyposis and a high incidence of gastric cancer and demonstrated the autosomal dominant pattern of inheritance. The current study described the histologic and immunohistologic features of the lesions in an attempt to clarify the mechanisms underlying gastric carcinogenesis in this family.

METHODS

The authors studied the histopathologic and histochemical features of several gastric specimens of nine members of this family and searched for the expression of carcinoembryonic antigen (CEA), p21 protein (ras oncogene), p53 protein (p53 suppressor gene), and simple mucin-type carbohydrate antigens (Tn, sialosyl-Tn, and T antigen before and after neuraminidase) and for the presence of Helicobacter pylori.

RESULTS

The two carcinomas available for histologic revision were of the diffuse type. One of them apparently originated from a hyperplastic polyp. Hyperplastic polyps were diagnosed in five of seven patients without carcinoma. The remaining two patients had marked foveolar hyperplasia. Chronic atrophic gastritis with complete intestinal metaplasia (IM) was seen in three patients. p53 protein was not expressed in any of the cases. CEA and ras p21 oncoprotein were found in six and eight cases, respectively (mainly in hyperplastic foveolar epithelium). Tn, sialosyl-Tn, and T antigen were expressed in every case. H. pylori colonization was detected in all but the two patients with carcinoma.

CONCLUSIONS

The authors concluded that foveolar hyperplasia/hyperplastic polyps play a key role in the development of diffuse carcinoma in this inherited polyposis, confined to the stomach, with hyperplastic phenotype. The genetic and environmental mechanisms underlying this particular situation remain to be clarified.

Endometrial polyp: another benign tumor characterized by 12q13-q15 changes

Clustering of aberrations to specific chromosome regions of benign tumors may indicate the location of genes related to the proliferative process. Although few endometrial polyps have been cytogenetically investigated, 6p21 band appears to be involved consistently in the chromosome changes. We report two cases of this type of benign tumor with chromosome rearrangements in 12q14-15, allowing identification of a second cytogenetic subgroup in endometrial polyps.