評估血漿Dickkopf-1做為肝癌診斷與篩檢之蛋白質標記

Abstract

背景與目的：Alpha胎兒蛋白（AFP）為目前最廣泛用於肝癌監測的生物標記，但其敏感度有限，因此需要找敏感度更好的生物標誌物來增強肝癌的篩檢。Dickkopf-1（DKK1）是Wingless(WNT)致癌途徑的抑制蛋白。先前研究發現血清DKK1在肝癌的診斷上效果比AFP更佳。我們的研究有兩個目的: 第一，使用病例對照研究重新評估血漿DKK1是否能成為B型肝炎(HBV)帶原者的肝癌診斷生物標記；第二，使用重疊病例對照研究評估血漿DKK1是否能用於B型肝炎帶原者之肝癌早期檢測生物標記。 材料與方法：重疊病例對照研究包括151個肝癌患者與361個經過配對的對照，他們是來自於1988年起徵募共4841名年齡大於30歲的男性HBV帶原者世代中之個案。病例對照研究包括303個徵募於多醫學中心臨床研究的肝癌臨床個案，並以重疊病例對照研究中的361個非肝癌個案作為對照組。血漿DKK1濃度利用酵素免疫分析法方法測定，而DKK1對於肝癌的診斷和早期檢測準確度則利用接收器運作指標曲線的曲線下面積(AUC-ROC)來計算。 結果：在病例對照研究中，血漿DKK1對肝癌診斷的總AUC值為0.5146 (P=0.218)。當患者依照肝癌期別分為早期肝癌與晚期肝癌之後，診斷肝癌的AUC值分別為0.4882 (P=0.5288)和0.5654 (P=0.0026)。在重疊病例對照研究中，血漿DKK1與肝癌有負向相關，調整年齡、ALT、HBV DNA之後，DKK1濃度第三分位數與第四分位數的odds ratio (OR)分別為0.40 (95%信賴區間：0.21~0.77)與0.46 (95%信賴區間：0.24~0.86)。在肝癌早期檢測方面，DKK1對於全部肝癌的AUC值為0.6107 (P=0.0064)，而當診斷出肝癌與血液抽取時間間隔區分成四組(即3年內、4-6年、7-9年、10-12年)之後，DKK1檢測肝癌之AUC值分別為0.5434 (P=0.9489)、0.6506 (P=0.0033)、0.6504 (P=0.0208)及0.5853 (P=0.2988)。 結論：血漿DKK1對於肝癌的診斷與早期檢測的準確性不佳，但它可能可以作為肝癌風險評估之生物標記。

Background and aims: α-fetoprotein (AFP) has been widely used as a biomarker for hepatocellular carcinoma (HCC) surveillance, but it has limited sensitivity. Finding more sensitive biomarkers for HCC surveillance is needed. Dickkopf-1 (DKK1) is an inhibitory protein involved in Wingless oncogenic pathways. A previous study has shown that serum DKK1 is a better biomarker than AFP for the diagnosis of HCC. Our specific aims of this study were twofold: 1) Using the case-control study design to reevaluate whether plasma DKK1 could be used as a biomarker for diagnosis of HCC in hepatitis B virus (HBV) carriers; and 2) Using the nested case-control study design to assess whether plasma DKK1 could be used for early detection of HCC in HBV carriers. Materials and Methods: The nested case-control study included a total of 151 HCC cases and 361 matched controls recruited from a cohort study of 4841 male HBV carriers initiated since 1988. For conducting case-control study, a case series of 303 clinical patients with HCC was recruited from a published multicenter study compared with the 361 HCC-free controls in the nested case-control study. Plasma DKK1 levels were measured by using Enzyme-Linked Immunosorbent Assay (ELISA). We need area under the curve of receiver operating characteristic (AUC-ROC) analysis to calculate the accuracy of DKK1 for diagnosis and screening of HCC. Results: In the case-control study, the overall AUC of DKK1 for the diagnosis of HCC was 0.5146 (P=0.218). When patients were classified as early and late–stage HCC, the AUC was 0.4882 (P=0.5288) for early stage and 0.5654 (P=0.0026) for late stage. In the nested case-control study, there was a negative association between plasma DKK1 and HCC, showing the odds ratios of 0.40 (95% confidence interval: 0.21 to 0.77) and 0.46 (95% confidence interval: 0.24 to 0.86), respectively, for the third and fourth quartile level of DKK1 relative to the first quartile level after adjustment for age, alanine aminotransferase and HBV DNA. The overall AUC of DKK1 for early detection of HCC was 0.6107 (P=0.0064). When the subjects who subsequently developed HCC were stratified into four groups (i.e., 0-3, 4-6, 7-9, and 10-12 years) according to the interval between blood draw and HCC diagnosis, the AUCs for the four groups of cases vs. controls were 0.5434 (P=0.9489), 0.6506 (P=0.0033), 0.6504 (P=0.0208) and 0.5853 (P=0.2988), respectively. Conclusion: The accuracy of plasma DKK1 was poor for either diagnosis or screening of HCC. However, plasma DKK1 may be used as a marker for the risk assessment of HCC.