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Expression of beclin‐1, an autophagy‐related protein, in gastric and colorectal cancers
Author(s) -
AHN CHANG HYEOK,
JEONG EUN GOO,
LEE JONG WOO,
KIM MIN SUNG,
KIM SUNG HEE,
KIM SUNG SOO,
YOO NAM JIN,
LEE SUG HYUNG
Publication year - 2007
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1111/j.1600-0463.2007.00858.x
Subject(s) - colorectal cancer , cancer research , carcinogenesis , tissue microarray , autophagy , cancer , immunohistochemistry , metastasis , tumor suppressor gene , biology , medicine , pathology , oncology , apoptosis , biochemistry
Autophagy plays important roles in both cell death and cell survival. Beclin‐1, a key regulator of autophagy formation, has been considered as a haploinsufficient tumor suppressor. Loss of expression or point mutation could serve as a mechanism of loss of beclin‐1 tumor suppressor function in cancers. However, our recent study revealed that point mutation of the beclin‐1 gene is a rare event in common human cancers. In this study we investigated beclin‐1 protein expression in 103 colorectal and 60 gastric carcinoma tissues by immunohistochemistry using a tissue microarray approach. In the cancers, expression of beclin‐1 was detected in 95% of the colorectal carcinomas and 83% of the gastric carcinomas. In contrast, normal mucosal cells of both stomach and colon showed no or very weak expression of beclin‐1. There was no significant association of beclin‐1 expression with clinocopathologic characteristics, including invasion, metastasis and stage. The beclin‐1 expression of colorectal and gastric cancers in the present study is quite in contrast to that of the breast cancers in the previous study, which showed a decreased beclin‐1 expression in breast cancer cells compared to normal breast cells. Our data indicate that beclin‐1 inactivation by loss of expression may not occur in colorectal and gastric cancers. Rather, increased expression of beclin‐1 in the malignant colorectal and gastric epithelial cells compared to their normal mucosal epithelial cells suggests that neo‐expression of beclin‐1 may play a role in both colorectal and gastric tumorigenesis.