G protein gamma 7 expression as a new clinicopathological marker in patients with intrahepatic cholangiocarcinoma.
OBJECTIVE
The signal alterations mediated by small G proteins such as Ras, Rho, and Rac have been reported in several cancers. The human G protein gamma 7 (G-gamma 7) gene, which is down-regulated in various digestive organ cancers, was recently identified and cloned. Thus, the G-gamma 7-coupled heterotrimeric G proteins may also contribute to carcinogenesis in human cancers.


METHODS
University hospital and medical institute of bioregulation.


METHODS
The clinicopathological significance of G-gamma 7 expression in 18 patients with intrahepatic cholangiocarcinoma (IHCC) was examined. The tumor-nontumor ratio of G-gamma 7 expression was determined using reverse transcription polymerase chain reaction analysis. To visualize the localization of G-gamma 7, an immunohistochemical study was performed.


METHODS
Clinicopathological significance of G-gamma 7 expression in human IHCC.


RESULTS
Expression of G-gamma 7 messenger RNA was lower in tumor tissue than in the corresponding nontumor tissue in 17 (94%) of 18 patients with IHCC. The mean tumor-nontumor ratio was 0.54. Eleven patients with tumor-nontumor ratios less than 0.5 showed significantly poorer differentiated IHCC than 7 with tumor-nontumor ratios of 0.5 and greater (P<.01). Decreased expression of G-gamma 7 protein in the carcinoma tissue, especially in the poorly differentiated IHCC tissue, was confirmed using immunohistochemical staining.


CONCLUSIONS
Reduced expression of G-gamma 7 is associated with the histological grade of IHCC and may therefore prove to be a useful marker for predicting the biological aggressiveness of human IHCC.
Utsunomiya
Tohru
T
Department of Surgery, Medical Institute of Bioregulation, Kyushu University, 4546 Tsurumibaru, Beppu 874-0838, Japan.
Inoue
Hiroshi
H
Taguchi
Ken-Ichi
K
Shimada
Mitsuo
M
Sugimachi
Keizo
K
Mori
Masaki
M
D000328:Adult; D000368:Aged; D001650:Bile Duct Neoplasms / Q000378:metabolism* / Q000473:pathology; D001653:Bile Ducts, Intrahepatic; D016009:Chi-Square Distribution; D018281:Cholangiocarcinoma / Q000378:metabolism* / Q000473:pathology; D015536:Down-Regulation; D005260:Female; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D020962:Heterotrimeric GTP-Binding Proteins