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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Histopathology 30 (1997), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Aberrant crypt foci (ACF) have been identified in the methylene-blue stained mucosa of the human colon. Some lines of evidence suggest that ACF may be precursors of colon cancer. The objective of the present study was to establish morphological criteria able to define and classify ACF in histological sections. Twenty-four colectomy specimens were collected after operation for colorectal cancer and fixed in 10% formalin. Strips of grossly normal mucosa were stained in a 0.2% solution of methylene blue in saline for 5–10 min. The strips were measured, put on a glass slide and observed under a light microscope at ×25. One hundred and fourteen ACF identified by topology were sectioned parallel to the muscularis mucosae. Eighty-four ACF were evident at histological examination and could be classified into three main groups: group A (61 ACF, 72.6%) including foci whose epithelial cells had regular nuclei, with only mild or focal crowding but no stratification, no mucin depletion and no dysplasia; group B (16 ACF, 19.1%), in which features of hyperplasia were evident; and group C (seven ACF, 8.3%) including foci with enlarged, crowded and stratified nuclei, mucin depletion, frequent mitoses, and evident dysplasia, diffuse or focal (mild in five cases, moderate in two) representing microadenomas. Finally, hyperplastic foci were significantly larger than foci of group A and C. Group B ACF were also more frequent in the rectum than in the colon. In conclusion, selected histological features allow the definition of groups of ACF, which may represent sequential steps in the development of human colorectal tumours.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The Muir–Torre syndrome (MTS) is an autosomal dominant genodermatosis characterized by the presence of sebaceous gland tumours, with or without keratoacanthomas, associated with visceral malignancies. We describe and characterize two families in which the ample phenotypic variability of MTS was evident. After clinical evaluation, the skin and visceral tumours of one member of a family with ‘classic’ MTS and one member of a family with a ‘peculiar’ MTS phenotype without sebaceous lesions, but with only multiple keratoacanthomas, were analysed for microsatellite instability (MSI) and by immunohistochemistry. Tumours of both individuals showed MSI, with a concomitant lack of MSH2 immunostaining in all evaluated skin and visceral lesions; moreover, in the proband of family 2 a constitutional mutation (C→T substitution leading to a stop codon) in the MSH2 gene was identified. We conclude that the diagnosis of MTS, which is mainly clinical, should take into account an ample phenotypic variability, which includes both cases with typical cancer aggregation in families and cases characterized by the association of visceral malignancies with multiple keratoacanthomas (without sebaceous lesions), without an apparent family history of cancer.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-2307
    Keywords: Colorectal cancer ; Hereditary nonpolyposis colorectal cancer ; Carbohydrate antigens ; Lectin histochemistry ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The simple mucin-type carbohydrate antigens Tn, sialosyl-Tn, T and the ‘cryptic’ sialylated variant of the last represent the mucin core oligosaccharide structures that are produced in the initial steps of the mucin biosynthetic pathway. Utilizing monoclonal antibodies anti-Tn antigen (HB-Tn1), anti-sialosyl-Tn antigen (HB-STn1), anti-T antigen (HB-T1) and the biotinylated Amaranthus caudatus agglutinin (ACA), we have investigated the expression of the simple mucin-type carbohydrate antigens in hereditary nonpolyposis colorectal cancer (HNPCC; 15 cases) compared with sporadic colorectal cancer (CRC; 60 cases) and normal colonic mucosa (30 cases). A variable positivity of Tn, sialosyl-Tn, T and the cryptic sialylated form of this latter antigen was encountered in both HNPCC and sporadic CRC cases; in addition, in normal colonic mucosa a constant reactivity was encountered only for Tn and the cryptic sialylated form of T, while negative results were always obtained for sialosyl-Tn and T antigens. Statistical analysis, performed using a Chi-square test, showed significantly lower (P=0.037) expression of sialosyl-Tn and higher (P=0.022) expression of T in HNPCC than in sporadic CRC, suggesting a greater presence of β1,3 galactosyl-transferase activity in HNPCC than in sporadic CRC. We were unable to identify a peculiar phenotype for HNPCC with simultaneous evaluation of reactivity for HB-Tn1, HB-STn1, HB-T1 and ACA; the biological significance of the preferential expression of T antigen in HNPCC remains to be investigated.
    Type of Medium: Electronic Resource
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