AIM:To study the expression of a disintegrin andmetalloproteinase 17 (ADAM17) mRNA in hepatocellularcarcinoma (HCC) and to evaluate the relationship betweenADAM17 mRNA expression and clinicopathological featuresof HCC.METHODS:Hepatocellular carcinomas (HCC) from 31 caseswere divided into small HCC (SHCC),nodular HCC (NHCC)and solitary large HCC (SLHCC) according to tumor diameterand the number of nodes.ADAN17 mRNA expressions werecompared among those groups by means of semi-quantitativereverse transcription polymerase chain reaction (RT-PCR).The relationship between ADAM17 mRNA expression leveland clinicopathological features of HCC was evaluated.RESULTS:NHCC had lower differentiation and was morefrequently of microvascular invasion (10/12) than SHCC(3/11) and SLHCC (3/8) (P<0.05),but no statistical differencewas observed between SHCC and SLHCC comparing theirclinicopathological features.ADAM17 mRNA expression wasdetected in 77.4% (24/31) of HCC tissues and was significantlyhigher than that in paired non-cancerous liver tissues inwhich only 35.5% (11/31) of the samples were detectedof the expression (P<0.05).The expression of ADAM17mRNA was much higher in NHCC than in SHCC and SLHCC(P<0.05),while no significant difference was discoveredbetween SHCC and SLHCC.The quantities of ADAM17mRNA were significantly higher in poorly differentiated HCCthan in well or moderately differentiated HCC,but nostatistical difference was found concerning liver cirrhosis,tumor capsule formation or microvascular invasion of thecancer.CONCLUSION:The increased expression of ADAM17 mayplay a key role in the development of HCC.The expressionlevels of ADAM17 mRNA varied among different pathologicaltypes of HCC.Lower mRNA expression of ADAM17 mRNAin SLHCC may be associated with the better molecularpathological features of SLHCC. AIM: To study the expression of a disintegrin and metalloproteinase 17 (ADAM17) mRNA in hepatocellular carcinoma (HCC) and to evaluate the relationship betweenADAM17 mRNA expression and clinicopathological featuresof HCC. METHODS: Hepatocellular carcinomas (HCC) from 31 caseswere divided into small HCC , nodular HCC (NHCC) and solitary large HCC (SLHCC) according to tumor diameterand the number of nodes. ADAN17 mRNA expressions werecompared among those groups by means of semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). The relationship between ADAM17 mRNA expression leveland clinicopathological features of HCC was evaluated .RESULTS: NHCC had lower differentiation and was more frequently scarlet lesions (10/12) than SHCC (3/11) and SLHCC (3/8) (p <0.05), but no statistical differencewas observed between SHCC and SLHCC comparing their clinicopathological features. ADAM17 mRNA expression wasdetected in 77.4% (24/31) of HCC tissues and was significantlyhigher than that in paired non-cancerous liver tissues in only 35.5% (11/31) of the samples were detected of the expression (P <0.05). The expression of ADAM17 mRNA was much higher in NHCC than in SHCC and SLHCC (P <0.05) while no significant difference was discovered in SHCC and SLHCC.The quantities of ADAM17 mRNA were significantly higher in poorly differentiated HCC, but nostatistical difference was found relative to liver cirrhosis, tumor capsule formation or microvascular invasion of the cancer. expression of ADAM17 mayplay a key role in the development of HCC.The expression levels of the ADAM17 mRNA of among pathologicaltypes of HCC.Lower mRNA expression of ADAM17 mRNA in SLHCC may be associated with the better molecularpathological features of SLHCC.