title: Importance of luminal membrane mesothelin expression in intraductal papillary mucinous neoplasms.
abstract: The present study demonstrated that luminal membrane mesothelin expression is a reliable prognostic factor in gastric cancer. Intraductal papillary mucinous neoplasms (IPMNs) often exhibit a spectrum of dysplasia, ranging between adenoma and carcinoma. Therefore, an immunohistochemical analysis of mesothelin expression in IPMN was performed in the present study, focusing on the localization of mesothelin. IPMNs were classified into two groups, IPMNs associated with invasive carcinoma and low-high (L-H) grade dysplasias. The tumors were classified as mesothelin-positive or -negative and in the mesothelin-positive cases, the localization of mesothelin was evaluated as luminal membrane- or cytoplasmic-positive. Among the 37 IPMNs, mesothelin expression was observed in 21 samples (56.8%), including 46.2% (12 out of 26) of the L-H dysplasia and 81.8% (9 out of 11) of the invasive carcinoma samples (P=0.071). Luminal membrane localization was observed in 10 samples (27%), including 15.4% (4/26) of the L-H dysplasia samples and 54.5% (6 out of 11) of the invasive carcinoma samples (P=0.022). Six patients experienced post-operative recurrence, with five of the recurrent tumors exhibiting mesothelin expression and all six exhibiting luminal membrane localization. It was concluded that immunohistochemical examinations for mesothelin expression and localization are clinically useful for prognostic assessments and decision making regarding further treatment subsequent to surgical procedures in patients with IPMN.
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan ; Department of Surgery, Hokkaido Social Work Association Obihiro Hospital, Obihiro, Hokkaido 080-0805, Japan ; Division of Gastroenterological and General Surgery, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan.
authors: Takahiro
authors: T
authors: Einama
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Hirofumi
authors: H
authors: Kamachi
authors: Department of Translational Pathology, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Hiroshi
authors: H
authors: Nishihara
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Shigenori
authors: S
authors: Homma
authors: Department of Pathology, Laboratory of Cancer Research, Hokkaido University School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Hiromi
authors: H
authors: Kanno
authors: Department of Pathology, Laboratory of Cancer Research, Hokkaido University School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Marin
authors: M
authors: Ishikawa
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Futoshi
authors: F
authors: Kawamata
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Yuji
authors: Y
authors: Konishi
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Masanori
authors: M
authors: Sato
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Munenori
authors: M
authors: Tahara
authors: Department of Surgery, JA Sapporo Kosei Hospital, Sapporo, Hokkaido 060-0033, Japan.
authors: Kuniaki
authors: K
authors: Okada
authors: Department of Pathology, JA Sapporo Kosei Hospital, Sapporo, Hokkaido 060-0033, Japan.
authors: Shunji
authors: S
authors: Muraoka
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Toshiya
authors: T
authors: Kamiyama
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Akinobu
authors: A
authors: Taketomi
authors: Department of Surgical Pathology, Hokkaido University Hospital, Sapporo, Hokkaido 060-8638, Japan.
authors: Yoshihiro
authors: Y
authors: Matsuno
authors: Division of Gastroenterological and General Surgery, Asahikawa Medical University, Asahikawa, Hokkaido 078-8510, Japan.
authors: Hiroyuki
authors: H
authors: Furukawa
authors: Department of General Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan.
authors: Satoru
authors: S
authors: Todo
keywords: intraductal papillary mucinous neoplasms; luminal membrane expression; mesothelin