| 特集名 | Villous Tumor | |
|---|---|---|
| 題名 | 病理の立場から (2) villous tumorの分子病理学的特徴 | |
| 発刊年月 | 2001年 01月 | |
| 著者 | 藤井 茂彦 | 京都大学医学部消化器病態学 |
| 著者 | 日下 利広 | 獨協医科大学病理学(人体分子) |
| 著者 | 甲斐原 司 | 京都大学医学部消化器病態学 |
| 著者 | 千葉 勉 | 獨協医科大学病理学(人体分子) |
| 著者 | 藤盛 孝博 | 獨協医科大学病理学(人体分子) |
| 【 要旨 】 | 要旨はありません。 | |
| Theme | Villous Tumor | |
|---|---|---|
| Title | Molecularpathological features of villous tumors | |
| Author | Shigehiko Fujii | Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kyoto University, Postgraduate School of Medicine |
| Author | Toshihiro Kusaka | Department of Surgical and Molecular Pathology, Dokkyo University School of Medicine |
| Author | Tsukasa Kaihara | Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kyoto University, Postgraduate School of Medicine |
| Author | Tsutomu Chiba | Department of Surgical and Molecular Pathology, Dokkyo University School of Medicine |
| Author | Takahiro Fujimori | Department of Surgical and Molecular Pathology, Dokkyo University School of Medicine |
| [ Summary ] | The definition of villous tumor has not been standarized. We consider villous tumors to have a shaggy pattern macroscopically whether they are benign or malignant. Histolopathologically, we classify adenomatous lesions as tubular adenomas, if a villous component is present on less than 25% of the tumor, as tubulovillous adenomas if the villous component is 25-75%, and as villous adenomas if the villous component is more than 75% of the tumor. As a rule, we consider the greater part of villous tumors to be villous adenomas. To clarify the molecularpathological features and pathogenetic pathways in villous adenoma, we evaluated K-ras codon 12 point mutation by using PCR-RFLP, overexpression of p53 gene products human gastric mucin (HGM) and MUC2, and pattern and labeling index (L.I.) of Ki-67 immunoreactivety. Several studies have indicated that K-ras mutation in villous and tubulovillous adenoma is more frequent than in tubular adenoma. In this study, K-ras mutation of villous adenoma was most frequent in adenomas of three subtypes. Overexpression of p53 gene products was not seen with villous adenoma, but was shown focally in a part of tubulovillous adenoma. HGM was overexpressed in tubulovillous adenoma with mild atypia, but HGM expression diminishes with the presence of severe atypia and where tubular architecture predominates. In villous adenoma, HGM overexpression is maintained, in spite of large adenomas. In villous adenoma, the Ki-67 staining pattern was transmural, but the L.I. was lower than for tubulovillous adenoma. We theorize that initial lesion of villous adenoma is tiny tubular and tubulovillous adenomas, because villous adenomas smaller than 1cm are uncommon. Mucinous carcinoma, with villous structures resemble villous adenomas molecular pathologically, because they have a high frequency of K-ras mutation and display a negative or sporadic expression of p53 gene products and display overexpression of HGM. The possibility exists that mucinous carcinoma, with villous structures, may derive from villous adenoma. |
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