Puetkasichonpasutha Janpen, Namwat Nisana, Sa-Ngiamwibool Prakasit, Titapun Attapol, Suthiphongchai Tuangporn
Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand.
Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
Asian Pac J Cancer Prev. 2020 Mar 1;21(3):791-798. doi: 10.31557/APJCP.2020.21.3.791.
Cholangiocarcinoma (CCA), a common cancer in northeastern Thailand, is a severe disease with poor prognosis and short survival time following diagnosis. DNA damage in CCA is believed to be caused by liver fluke infection in combination with exposure to carcinogens. p53, a tumor suppressor, is the most mutated gene in human cancers including liver fluke-associated CCA. Hence, expression patterns of p53 and its target genes may be useful for diagnosis and/or prognosis of CCA patients.
Differential mRNA expression of p53 and its target genes, namely, FUCA1, ICAM2 MDM2, p21, PAI-1, S100A9, and WIP1 in CCA tissue samples (n = 30) relative to matched adjacent non-tumor tissues was determined by quantitative RT-PCR and compared to clinicopathological features. Level of p53 protein was determined by immunohistochemistry and correlated with the expression of its target genes.
Immunohistochemistry showed elevation of p53 protein level in 77% of the cases, while RT-PCR showed downregulation of p53 mRNA and its seven target genes in 23% and 47-97% of the samples. PAI-1 was down-regulated in almost all CCA samples, thus highlighting it as a potential diagnostic marker for CCA. However, no significant clinical associations were found except for down-regulation of WIP1 that was significantly correlated with non-papillary type tissue (p-value = 0.001) and with high p53 protein level (p-value = 0.007).
Our results demonstrated statistically significant association between down-regulation of WIP1 with non-papillary type and with high p53 protein level, and PAI-1 was down-regulated in almost all CCA. Therefore, expression level of WIP1 and PAI-1 may be useful for predicting p53 functional status and as a potential diagnostic marker of CCA, respectively.
胆管癌（CCA）是泰国东北部常见的一种癌症，是一种严重疾病，预后较差，诊断后生存时间短。CCA中的DNA损伤被认为是由肝吸虫感染以及接触致癌物共同导致的。p53作为一种肿瘤抑制因子，是包括与肝吸虫相关的CCA在内的人类癌症中突变最多的基因。因此，p53及其靶基因的表达模式可能有助于CCA患者的诊断和/或预后评估。
通过定量逆转录聚合酶链反应（RT-PCR）测定CCA组织样本（n = 30）中p53及其靶基因（即FUCA1、ICAM2、MDM2、p21、PAI-1、S100A9和WIP1）相对于匹配的相邻非肿瘤组织的差异mRNA表达，并与临床病理特征进行比较。通过免疫组织化学测定p53蛋白水平，并将其与靶基因的表达相关联。
免疫组织化学显示77%的病例中p53蛋白水平升高，而RT-PCR显示23%的样本中p53 mRNA及其七个靶基因下调，47%-97%的样本中出现下调。几乎所有CCA样本中PAI-1均下调，因此突出了其作为CCA潜在诊断标志物的地位。然而，除了WIP1下调与非乳头状类型组织显著相关（p值 = 0.001）以及与高p53蛋白水平显著相关（p值 = 0.007）外，未发现其他显著的临床关联。
我们的结果表明，WIP1下调与非乳头状类型以及高p53蛋白水平之间存在统计学上的显著关联，并且几乎所有CCA中PAI-1均下调。因此，WIP1和PAI-1的表达水平可能分别有助于预测p53功能状态以及作为CCA的潜在诊断标志物。
