AIM:To study the difference in gene expression betweensolitary large hepatocellular carcinoma(SLHCC)and nodularhepatocellular carcinoma(NHCC).METHODS:Polymerase chain reaction(PCR)products of8464 human genes were spotted on a chip in array.DNAswere then fixed on a glass plate.Total RNA was isolated fromfreshly excised human SLHCC(n=7)and NHCC(n=15)tissues,and was reversely transcribed to cDNAs with theincorporation of fluorescent dUTP for preparation ofhybridization probes.The mixed probes were then hybridizedto the cDNA microarray.After highly stringent washing,cDNA microarray was scanned for the fluorescent signalsto display the difference between the two kinds of HCC.Inaddition,the expression of RhoCand protocadherin LKCwas also detected with the reverse transcriptase polymerasechain reaction(RT-PCR)method.RESULTS:Among the 8 464 human genes,668(7.89%)genes were expressed differentially at the mRNA levelsbetween SLHCC and NHCC.Three hundred and fifty five(4.19%)genes,including protocadherin LKC,were up-regulated,whereas 313(3.70%)genes,including RhoC,were down-regulated.The mRNA expression levels of RhoCand protocadherin LKCwere confirmed by RT-PCR.Analysisof differentially expressed genes confirmed that ourmolecular data obtained by cDNA microarray were consistentwith the published biochemical and clinical observations ofSLHCC and NHCC.CONCLUSION:cDNA microarray is an effective techniquein screening the difference in gene expression betweenSLHCC and NHCC. Many of these differentially expressedgenes are involved in the invasion and metastasis of HCC.Further analysis of these genes will help to understand thedifferent molecular mechanisms of SLHCC and NHCC. AIM: To study the difference in gene expression between solid large hepatocellular carcinoma (SLHCC) and nodularhepatocellular carcinoma (NHCC) .METHODS: Polymerase chain reaction (PCR) products of8464 human genes were spotted on a chip in array. DNAswere then fixed on a glass plate . Total RNA was isolated from freshly excised human SLHCC (n = 7) and NHCC (n = 15) tissues, and was reversely transcribed to cDNAs with theincorporation of fluorescent dUTP for preparation of hybridization probes. The mixed probes were then hybridized to the cDNA microarray. After highly stringent washing, cDNA microarray was scanned for the fluorescent signal display the difference between the two kinds of HCC. addition, the expression of RhoCand protocadherin LKCwas also detected with the reverse transcriptase polymerase chain reaction (RT-PCR) method. 464 human genes, 668 (7.89%) genes were expressed differentially at the mRNA levels between SLHCC and NHCC.Three hundred and fifty five (4.19%) genes, including proto The expression level of RhoCand protocadherin LKCwere confirmed by RT-PCR. Analysis of differentially expressed genes confirmed that our molecular data obtained by cDNA microarray were consistentwith the published biochemical and clinical observations of SLHCC and NHCC.CONCLUSION: cDNA microarray is an effective technique in screening the difference in gene expression betweenSLHCC and NHCC. Many of these differentially expressed genes are involved in the invasion and metastasis of HCC. Further analysis of these genes will help to understand thedifferent molecular mechanisms of SLHCC and NHCC.