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Up‐regulation of lysozyme production in colonic adenomas and adenocarcinomas
Author(s) -
Siu Tsan Yuen,
Maria Pik Wong,
Lap Ping Chung,
Sandy Chan,
N. Wah Cheung,
J.C.M. Ho,
Suet Yi Leung
Publication year - 1998
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1046/j.1365-2559.1998.00339.x
Subject(s) - lysozyme , immunohistochemistry , epithelium , biology , pathology , crypt , adenoma , adenocarcinoma , cancer , medicine , endocrinology , biochemistry , genetics
Aims: The presence of lysozyme protein in some gastric adenomas and adenocarcinomas has been well documented. There have been relatively few studies investigating the presence of lysozyme in tumours of the large intestine and they show contrasting results. We aim to investigate the cellular source and expression of lysozyme in colonic adenomas and adenocarcinomas. Methods and results: We randomly selected 29 and 27 colonic adenomas and adenocarcinomas, respectively. Using in‐situ hybridization (ISH) and immunohistochemistry (IHC), we found an up‐regulation of lysozyme in the dysplastic epithelium of all the adenomas studied, with more than 80% of cases expressing moderate to strong signals. Although the up‐regulation of lysozyme was also observed in adenocarcinomas, only 30% of the cases showed moderate to strong signals, mostly with an uneven distribution. Down‐regulation of lysozyme in the severely dysplastic and invasive foci were noted in some cases of adenoma with malignant transformation. Normal colonic glands were consistently negative for lysozyme at both the mRNA and the protein level, but inflamed and immature regenerative colonic epithelium at the crypt base showed positive signals in a similar pattern to those observed in the dysplastic epithelium of the adenomas. Conclusions: Our results confirm that colonic epithelium can produce lysozyme and its expression is up‐regulated in the dysplastic epithelium in adenomas and in invasive cancer cells. It is interesting that regenerative colonic epithelium showed a similar pattern of lysozyme expression as in adenomas. The loss of lysozyme secreting phenotype in most of the invasive tumours suggests that lysozyme may not confer an advantage to tumour progression.