Upregulation of plasma C9 protein in gastric cancer patients.
Gastric cancer is one of the leading causes of cancer-related deaths worldwide. Current biomarkers used in the clinic do not have sufficient sensitivity for gastric cancer detection. To discover new and better biomarkers, protein profiling on plasma samples from 25 normal, 15 early-stage and 21 late-stage cancer was performed using an iTRAQ-LC-MS/MS approach. The level of C9 protein was found to be significantly higher in gastric cancer compared with normal subjects. Immunoblotting data revealed a congruent trend with iTRAQ results. The discriminatory power of C9 between normal and cancer states was not due to inter-patient variations and was independent from gastritis and Helicobacter pylori status of the patients. C9 overexpression could also be detected in a panel of gastric cancer cell lines and their conditioned media compared with normal cells, implying that higher C9 levels in plasma of cancer patients could be attributed to the presence of gastric tumor. A subsequent blind test study on a total of 119 plasma samples showed that the sensitivity of C9 could be as high as 90% at a specificity of 74%. Hence, C9 is a potentially useful biomarker for gastric cancer detection.
Chong
Poh-Kuan
PK
Cancer Science Institute of Singapore, Singapore, Singapore.
Lee
Huiyin
H
Loh
Marie Chiew Shia
MC
Choong
Lee-Yee
LY
Lin
Qingsong
Q
So
Jimmy Bok Yan
JB
Lim
Khong Hee
KH
Soo
Ross Andrew
RA
Yong
Wei Peng
WP
Chan
Siew Pang
SP
Smoot
Duane T
DT
Ashktorab
Hassan
H
Yeoh
Khay Guan
KG
Lim
Yoon Pin
YP
D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D045744:Cell Line, Tumor; D003186:Complement C9 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000097:blood*; D015854:Up-Regulation
D014408:Biomarkers, Tumor; D003186:Complement C9