Increased expression of Gab2, a scaffolding adaptor of the tyrosine kinase signalling, in gastric carcinomas.
OBJECTIVE
Mounting evidence indicates that alterations of protein kinase signalling pathways play crucial roles in the pathogenesis of cancers. Gab2 (Grb2-associated binding protein 2), a member of the family of Gab scaffolding adaptors, transmits and amplifies the signals from receptor tyrosine kinases. A recent study demonstrated that Gab protein was over-expressed in breast cancers, and the over-expressed Gab2 increased proliferation and invasion of the cells, indicating that Gab2 is an oncogenic protein. However, the roles of Gab in other cancers are largely unknown.


METHODS
In this study, to see whether Gab2 expression could be a characteristic of gastric cancers, we analysed the expression of Gab2 in 60 gastric adenocarcinomas by immunohistochemistry using a tissue microarray.


RESULTS
In the normal gastric mucosal epithelial cells, Gab2 protein was expressed in parietal and zymogen cells, but not in other mucosal epithelial cells. In the cancer cells, Gab2 expression was detected in 40 (67%) of the 60 gastric adenocarcinomas. The Gab2 expression was observed in 12 (60%) of the 20 early gastric carcinomas and 28 (70%) of the 40 advanced gastric carcinomas. There was no significant association of Gab2 expression with clinocopathological characteristics, including invasion, metastasis and stage.


CONCLUSIONS
Our data indicate that Gab2 over-expression is a feature not only of breast cancers, but also of gastric cancers. Increased expression of Gab2 in malignant gastric cells compared with normal epithelial cells suggests that Gab2 expression may play a role in gastric cancer development.
Lee
Sung Hak
SH
Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Jeong
Eun Goo
EG
Nam
Suk Woo
SW
Lee
Jung Young
JY
Yoo
Nam Jin
NJ
Lee
Sug Hyung
SH
D048868:Adaptor Proteins, Signal Transducing / Q000096:biosynthesis*; D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D046888:Tissue Array Analysis
D048868:Adaptor Proteins, Signal Transducing; C490895:GAB2 protein, human; D011505:Protein-Tyrosine Kinases