An RNA-based signature enables high specificity detection of circulating tumor cells in hepatocellular carcinoma
An RNA-based signature enables high specificity detection of circulating tumor cells in hepatocellular carcinoma
复制标题
DOI：
10.1073/pnas.1617032114
复制
发表时间：
2017-01-31
影响因子：
11.1
通讯作者：
Haber, Daniel A.
中科院分区：
文献类型：
--
作者：
Kalinich, Mark;Bhan, Irun;Haber, Daniel A.
循环肿瘤细胞（CTCs）由侵袭性癌症脱落进入血流，但通过显微镜识别这些罕见细胞所固有的困难阻碍了它们在癌症监测或筛查中的常规应用。我们最近描述了一种高通量微流控CTC - iChip，它能有效地从血液样本中去除造血细胞，并富集具有保存完好的RNA的CTCs。应用基于RNA的数字PCR来检测源自CTCs的特征，或许因此能够在血液样本中实现基于组织谱系的高度准确的癌症检测。作为原理验证，我们研究了肝细胞癌（HCC），这是一种源自具有独特基因表达谱的肝细胞的癌症。在确定了10种肝脏特异性转录本的数字特征后，我们使用交叉验证的逻辑回归模型来识别16名未经治疗的肝细胞癌患者中的9名（56%）存在源自肝细胞癌的CTCs，而在31名有发展为肝细胞癌风险的非恶性肝病患者中只有1名（3%）存在（P < 0.0001）。接受治疗的患者的CTCs阳性评分下降：32名接受治疗的患者中有9名（28%）为阳性，而在15名接受根治性消融、手术或肝移植的患者中只有1名（7%）为阳性。基于RNA的数字CTCs评分与肝细胞癌的标准血清蛋白标志物甲胎蛋白无关（P = 0.57）。对在高危肝硬化患者中依次使用这两种正交标志物进行肝癌筛查进行建模，得出的阳性预测值和阴性预测值分别为80%和86%。因此，数字RNA定量是一种灵敏且特异的CTCs检测结果，能够实现高通量临床应用，例如在病毒性肝炎和肝硬化流行的人群中对肝细胞癌进行无创筛查。
Circulating tumor cells (CTCs) are shed into the bloodstream by invasive cancers, but the difficulty inherent in identifying these rare cells by microscopy has precluded their routine use in monitoring or screening for cancer. We recently described a high-throughput microfluidic CTC-iChip, which efficiently depletes hematopoietic cells from blood specimens and enriches for CTCs with well-preserved RNA. Application of RNA-based digital PCR to detect CTC-derived signatures may thus enable highly accurate tissue lineage-based cancer detection in blood specimens. As proof of principle, we examined hepatocellular carcinoma (HCC), a cancer that is derived from liver cells bearing a unique gene expression profile. After identifying a digital signature of 10 liver-specific transcripts, we used a cross-validated logistic regression model to identify the presence of HCC-derived CTCs in nine of 16 (56%) untreated patients with HCC versus one of 31 (3%) patients with nonmalignant liver disease at risk for developing HCC (P < 0.0001). Positive CTC scores declined in treated patients: Nine of 32 (28%) patients receiving therapy and only one of 15 (7%) patients who had undergone curative-intent ablation, surgery, or liver transplantation were positive. RNA-based digital CTC scoring was not correlated with the standard HCC serum protein marker alpha fetoprotein (P = 0.57). Modeling the sequential use of these two orthogonal markers for liver cancer screening in patients with high-risk cirrhosis generates positive and negative predictive values of 80% and 86%, respectively. Thus, digital RNA quantitation constitutes a sensitive and specific CTC readout, enabling high-throughput clinical applications, such as noninvasive screening for HCC in populations where viral hepatitis and cirrhosis are prevalent.