OBJECTIVE To study the differential expression of COP9,JAK2,HSPS and NADH genes and their relationship with taxol resistance in ovarian carcinoma.METHODS The up-regulated genes for JAK2,HSPs and NADH,and the down-regulated COP9 gene,which have been demonstrated by a micro-array from our previous study,were examined by the reverse transcription-polymerase chain reaction(RT-PCR) and real-time-PCR in 33 tissue samples from ovarian cancer patients who previously had received taxol-based chemotherapy(Group1),and from 21 ovarian cancer cases who had never received chemotherapy before operation(Group2).RESULTS The expression rate of COP9 in Group 1 was shown to be markedly lower compared to Group 2(P = 0.000).However the expression rates of JAK2,HSPs and NADH in Group 1 were significantly higher than those in Group 2(all P = 0.000).The expression of COP9,HSPs and NADH showed no significant differences related to the histological grade.However,signifi cant higher expression of JAK2 was seen in Grade 3 compared to Grade 1～2(P = 0.000).We performed real-time PCR to conf irm the above fi ndings showing that the level of COP9 gene copies of Group 1 was much lower than that of Group 2(P = 0.007).Similarly,HSPs and NADH had significantly higher copy numbers in Group 1 compared to those patients who had not undergone chemotherapy(Group 2)(P = 0.018,P = 0.024,respectively).We also found that the JAK2 gene copy concentration in a TAX group was higher than in a non-TAX group(P = 0.001).In addition,we conf irmed a higher copy concentration of the JAK2 gene in Grade 3 compared to Grade 1～2 tumors(P = 0.000),though no signifi cant difference in the expression rates and gene copy concentrations of the 4 genes were seen among variable tumor types.CONCLUSION The down-regulation of COP9 and up-regulation of JAK2,HSPs,and NADH genes are related to the mechanism of drug-resistance in ovarian cancers. OBJECTIVE To study the differential expression of COP9, JAK2, HSPS and NADH genes and their relationship with taxol resistance in ovarian carcinoma. METHODS The up-regulated genes for JAK2, HSPs and NADH, and the down-regulated COP9 gene, which have have been demonstrated by a micro-array from our previous study, were examined by the reverse transcription-polymerase chain reaction (RT-PCR) and real-time-PCR in 33 tissue samples from ovarian cancer patients who previously had received taxol-based chemotherapy (Group 1) , and from 21 ovarian cancer cases who had never received chemotherapy before operation (Group2) .RESULTS The expression rate of COP9 in Group 1 was shown to be markedly lower compared to Group 2 (P = 0.000) .Wow the expression rates of JAK2, HSPs and NADH in Group 1 were significantly higher than those in Group 2 (all P = 0.000). The expression of COP9, HSPs and NADH showed no significant differences related to the histological grade. However, signifi cant higher expression of JAK2 was seen in Grade 3 compared to Grade 1 ~ 2 (P = 0.000). We performed real-time PCR to confirm the above fi ndings that that level of COP9 gene copies of Group 1 was much lower than that of Group 2 (P = 0.007 .Similarly, HSPs and NADH had significantly higher copy numbers in Group 1 compared to those patients who had not undergone chemotherapy (Group 2) (P = 0.018, P = 0.024, respectively) .We also found that the JAK2 gene copy concentration in a TAX group was higher than in a non-TAX group (P = 0.001). In addition, we conf irmed a higher copy concentration of the JAK2 gene in Grade 3 compared to Grade 1-2 tumors (P = 0.000), though no signifi cant difference in the expression rates and gene copy concentrations of the 4 genes were seen among variable tumor types. CONCLUSION The down-regulation of COP9 and up-regulation of JAK2, HSPs, and NADH genes are related to the mechanism of drug-resistance in ovarian cancers.