Overexpression of connexin 26 in carcinoma of the pancreas.
Contrary to the previously purported role of gap junction (GJ) associated-protein connexin 26 (Cx26) as a tumor suppressor, increased expression of Cx26 has recently been demonstrated in several human malignancies. Surprisingly, this high expression is reportedly related to poor prognosis in squamous cell lung carcinoma and breast cancer. In this study, we examined levels of Cx26 in various human gastrointestinal (GI) carcinomas, with a focus on pancreatic carcinomas, using immunohistochemistry. Many GI carcinomas displayed abundant Cx26 expression, predominantly in the cytoplasm. Cx26 was detected in 5/8 gastric cancers (62.5%), 6/8 squamous cell carcinomas of the esophagus (75.0%), 7/8 pancreatic cancers (87.5%) and 7/8 colon cancer cases (87.5%). However, Cx26 expression was not present in hepatocellular carcinoma (HCC, 0/8). Extensive immunohistochemical examination was performed on pancreatic carcinomas, revealing strong expression of Cx26 protein in 30/43 cases (70%), weak expression in 6/43 (14%) and no expression in 7/43 (16%). The present study demonstrated up-regulated Cx26 expression in a considerable percentage of GI carcinomas, with the exception of HCC. Our findings suggest that Cx26 may be involved in some of the malignant processes of GI cancers, and especially in pancreatic carcinomas.
Kyo
Naganori
N
Department of Surgery, Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.
Yamamoto
Hirofumi
H
Takeda
Yutaka
Y
Ezumi
Koji
K
Ngan
Chew Yee
CY
Terayama
Motokazu
M
Miyake
Masakazu
M
Takemasa
Ichiro
I
Ikeda
Masataka
M
Doki
Yuichiro
Y
Dono
Keizo
K
Sekimoto
Mitsugu
M
Nojima
Hiroshi
H
Monden
Morito
M
D002277:Carcinoma / Q000378:metabolism*; D000072259:Connexin 26; D017630:Connexins / Q000378:metabolism*; D005770:Gastrointestinal Neoplasms / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D010190:Pancreatic Neoplasms / Q000378:metabolism*; D015854:Up-Regulation
D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26