Protein profiling in hepatocellular carcinoma by label-free quantitative proteomics in two west African populations.
BACKGROUND
Hepatocellular Carcinoma is the third most common cause of cancer related death worldwide, often diagnosed by measuring serum AFP; a poor performance stand-alone biomarker. With the aim of improving on this, our study focuses on plasma proteins identified by Mass Spectrometry in order to investigate and validate differences seen in the respective proteomes of controls and subjects with LC and HCC.


METHODS
Mass Spectrometry analysis using liquid chromatography electro spray ionization quadrupole time-of-flight was conducted on 339 subjects using a pooled expression profiling approach. ELISA assays were performed on four significantly differentially expressed proteins to validate their expression profiles in subjects from the Gambia and a pilot group from Nigeria. Results from this were collated for statistical multiplexing using logistic regression analysis.


RESULTS
Twenty-six proteins were identified as differentially expressed between the three subject groups. Direct measurements of four; hemopexin, alpha-1-antitrypsin, apolipoprotein A1 and complement component 3 confirmed their change in abundance in LC and HCC versus control patients. These trends were independently replicated in the pilot validation subjects from Nigeria. The statistical multiplexing of these proteins demonstrated performance comparable to or greater than ALT in identifying liver cirrhosis or carcinogenesis. This exercise also proposed preliminary cut offs with achievable sensitivity, specificity and AUC statistics greater than reported AFP averages.


CONCLUSIONS
The validated changes of expression in these proteins have the potential for development into high-performance tests usable in the diagnosis and or monitoring of HCC and LC patients. The identification of sustained expression trends strengthens the suggestion of these four proteins as worthy candidates for further investigation in the context of liver disease. The statistical combinations also provide a novel inroad of analyses able to propose definitive cut-offs and combinations for evaluation of performance.
Nuffield Department of Medicine, Henry Wellcome Building for Molecular Physiology - University of Oxford, Oxford, Oxfordshire, United Kingdom.
Haddy K S
HK
Fye
Cynthia
C
Wright-Drakesmith
Holger B
HB
Kramer
Suzi
S
Camey
Andre
A
Nogueira da Costa
Adam
A
Jeng
Alasana
A
Bah
Gregory D
GD
Kirk
Mohamed I F
MI
Sharif
Nimzing G
NG
Ladep
Edith
E
Okeke
Pierre
P
Hainaut
Simon D
SD
Taylor-Robinson
Benedikt M
BM
Kessler
Maimuna E
ME
Mendy
D000328:Adult; D000354:Africa, Western; D016632:Apolipoprotein A-I / Q000097:blood / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000097:blood / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000378:metabolism*; D016022:Case-Control Studies; D003176:Complement C3 / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006466:Hemopexin / Q000378:metabolism; D019694:Hepatitis B, Chronic / Q000150:complications; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood / Q000150:complications / Q000378:metabolism; D008113:Liver Neoplasms / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000378:metabolism*; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D020543:Proteome; D040901:Proteomics / Q000379:methods; D012372:ROC Curve; D015203:Reproducibility of Results; D055815:Young Adult; D000515:alpha 1-Antitrypsin / Q000097:blood / Q000378:metabolism
D016632:Apolipoprotein A-I; D014408:Biomarkers, Tumor; D003176:Complement C3; D020543:Proteome; D000515:alpha 1-Antitrypsin; D006466:Hemopexin