Background: The purpose of this study was to identify the expression of phosphatase and tensin homolog (PTEN) and its diagnostic value in colorectal cancer (CRC).Methods: The expression level of serum PTEN at mRNA and protein level were determined using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses, respectively. Chi-square test was employed to explore the relationship between PTEN expression and clinical features of CRC patients. The receiver operating characteristics (ROC) curve was established to evaluate the diagnostic performance of PTEN in CRC.Results: The expression of serum PTEN was significantly lower in patients with CRC than that in healthy controls both at mRNA and protein level (p < .05). Also, the low PTEN expression was significantly related to serosal invasion, lymph node metastasis and Ki-67, but had no relation with age, sex, tumor depth and tumor site. The area under ROC curve of 0.810 corresponding with a sensitivity of 97.79% and a specificity of 70.31% were obtained, which suggested PTEN could act as a diagnostic marker for CRC.Conclusion: Altogether, serum PTEN expression was down-regulated and it participated in the development of CRC. Besides, it could act as an efficient and independent diagnostic marker for CRC patients.

中文翻译：

---

大肠癌患者血清中PTEN mRNA的水平：病例对照研究。

背景：本研究的目的是鉴定磷酸酶和张力蛋白同源物（PTEN）的表达及其在大肠癌（CRC）中的诊断价值。方法：采用定量real-time方法检测血清中PTEN在mRNA和蛋白质水平上的表达水平。时间聚合酶链反应（qRT-PCR）和蛋白质印迹分析。卡方检验用于探讨PTEN表达与CRC患者临床特征之间的关系。建立了接受者操作特征（ROC）曲线以评估PTEN在CRC中的诊断性能。结果：CRC患者的血清PTEN表达在mRNA和蛋白质水平上均显着低于健康对照组（p <.05 ）。此外，PTEN的低表达与浆膜浸润显着相关，淋巴结转移和Ki-67，但与年龄，性别，肿瘤深度和肿瘤部位无关。ROC曲线下面积为0.810，灵敏度为97.79％，特异度为70.31％，提示PTEN可作为CRC的诊断指标。结论：血清PTEN表达下调，参与了CRC的诊断。 CRC的发展。此外，它可以作为CRC患者的有效且独立的诊断标记。