Aptamers-based Molecular Classiifcation Of Primary Hepatic Carcinoma

Background and objectives: Aptamers are oligonucleotides capable of bindingto targets with high specificity and affinity, which are selected from a syntheticsingle-strand random oligonucleotide library by SELEX (systematic evolution ofligands by exponential enrichment) and are promising in diagnosis and therapy ofdiseases. Molecular classification is a new classification system based on molecularcharacteristics of a disease, which is of great significance in the individual diagnosisand treatment. In our previous work, a group of aptamers against the sera of primaryhepatic carcinoma (PHC) were evolved and valuable in the diagnosis of PHC. In thepresent study, we will analyze the feasibility and value of the aptamer assay resultsin the molecular classification of PHC.Methods: Thirteen aptamers against liver cancer sera were used to detect325serum specimens of PHC in our previous work, and the integrated grey-index of thefree aptamer band of each specimen was obtained. Clinical data includingdemography, etiology, and laboratory results and imaging findings were collected byreviewing the medical documents of the PHC patients. The correlations betweenaptamers were analyzed by Pearson correlation analysis. The aptamers wereclustered by Ward minimum variance method and the Euclidean distance square. Thecorrelations between aptamers and clinical data were analyzed by Spearmancorrelation analysis. The PHC clustering was performed by two step clustering withthe detection results of aptamers as a variable. The different significances of clinicaldata between subtypes determined by clustering were tested with the chi-square test,t test and/or variance analysis. All the statistical analyses were finished by softwareSPSS13.0.Results:(1) The correlations were weak among most of13aptamers withcorrelation coefficients from0.2to0.5, but several aptamers had no or obviouscorrelations with others. Thirteen aptamers could be clustered into4groups.(2) Theaptamers were correlated with partial clinical and laboratory data of PHC patients,but which were different among aptamers:8aptamers relating to liver cirrhosisbackground,7aptamers to liver function,7aptamers to INR,6aptamers to tumorsize,6aptamers to PLT,4aptamers to TBIL,4aptamers to Cl-,3aptamers to WBC,3aptamers to BUN, and some aptamers relating to AST, GGT, AKP, ALB, TG, HDL, APTT, MELD grade and age.(3) Liver cancer could be clustered into2～4subgroups by sample clustering with aptamers. Partial clinical and laboratoryparameters of PHC patients were significantly different between or amongsubgroups, and there were different in significantly different parameters among theaptamers: significant difference of liver cirrhosis background existing in8aptamers,tumor size in7aptamers, liver functional status in7aptamers, PLT count in7aptamers, INR in6aptamers, Cl-in5aptamers, AKP in3aptamers, ALB in3aptamers, K+in3aptamers, RBC in3aptamers, TBIL in2aptamers, GGT in2aptamers, grade of MELD in2aptamers, age in2aptamers, TP in2aptamers, HDLin2aptamers, Ca2+in2aptamers, WBC in2aptamers, PT in2aptamers, and sex,CA19-9, ALT, AST, BUN, TG, Na+, Hb and APTT in some individual aptamers.Conclusions:(1) The correlations are generally weak among13nucleic acidaptamers which could be clustered into4groups, suggesting that13aptamers mightbe against different targets in PHC serum.(2) Thirteen aptamers are correlated withpartial clinical and laboratory parameters of PHC patients, indicating that they couldreflect clinical features of liver cancer to some extent.(3) Liver cancer cases can beclustered into2~4subgroups by sample clustering with aptamers and parts ofclinical and laboratory data between or among subgroups are different significantly,suggesting that aptamer-based molecular classification of PHC is of clinical value.(4)The correlations between13aptamers and clinical and laboratory parameters and thedifferences of clinical and laboratory data between or among subgroups are differentamong individual aptamers, suggesting that this group of aptamers could reflectclinical characteristics of PHC in different aspects.