BACKGROUND Methylated SFRP2 was previously reported as a non-invasive biomarker for colorectal cancer (CRC) detection with a relatively low sensitivity for early stage CRC. The purpose of this study was to evaluate the performance of a new plasma based CRC screening assay, SpecColon test, which tested methylated SFRP2 and SDC2 simultaneously in a single qPCR reaction, in detecting CRC and advanced adenomas (AA). METHOD One milliliter plasma of 122 CRC patients, 12 AA patients, 93 patients with benign polyps, and 91 normal individuals were collected from the Affiliated Hospital of Xuzhou Medical University, and all samples were examined by SpecColon test. RESULTS The sensitivities for detecting AA and CRC by methylated SFRP2 alone were 50.0% (95% CI: 22.2-77.7%) and 63.1% (95% CI: 53.9-71.5%) with a specificity of 90.1% (95% CI: 81.6-95.1%). The sensitivities by methylated SDC2 alone were 33.3% (95% CI: 11.3-64.6%) and 56.6% (95% CI: 47.3-65.4%) with a specificity of 95.6% (95% CI: 88.5-98.6%). However, when methylated SFRP2 and methylated SDC2 were combined, the sensitivities for AA and CRC detection improved to 58.3% (95% CI: 28.6-83.5%) and 76.2% (95% CI: 67.5-83.3%) with a specificity of 87.9% (95% CI: 79.0-93.5%). The positive detection rates of benign polyp group and normal control group showed no significant difference (p > 0.01), whereas AA and CRC groups had significantly higher positive detection rates than normal individual group (p < 0.001). CONCLUSION The sensitivities for AA and early stage CRC by combined test of methylated SFRP2 and methylated SDC2, the so called SpecColon test, improved upon those by either biomarker alone without significant impact on the specificity. It has the potential to become a powerful, convenient and highly effective screening tool for early CRC screening.

中文翻译：

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基于甲基化的SDC2和SFRP2的基于血浆的新型早期大肠癌筛查方法。

背景技术以前，甲基化的SFRP2被报道为用于大肠癌（CRC）检测的非侵入性生物标记，其对早期CRC的敏感性相对较低。这项研究的目的是评估新的基于血浆的CRC筛查测定法SpecColon测试，该测试在单个qPCR反应中同时测试甲基化的SFRP2和SDC2在检测CRC和晚期腺瘤（AA）中的性能。方法从徐州医科大学附属医院收集122例CRC患者，12例AA患者，93例良性息肉患者和91例正常人的1毫升血浆，并对所有样本进行SpecColon检测。结果仅通过甲基化的SFRP2检测AA和CRC的敏感性为50.0％（95％CI：22.2-77.7％）和63.1％（95％CI：53.9-71.5％），特异性为90.1％（95％CI：81.6） -95.1％）。甲基化的SDC2单独的敏感性为33.3％（95％CI：11.3-64.6％）和56.6％（95％CI：47.3-65.4％），特异性为95.6％（95％CI：88.5-98.6％）。但是，将甲基化的SFRP2和甲基化的SDC2结合使用时，AA和CRC检测的灵敏度分别提高到58.3％（95％CI：28.6-83.5％）和76.2％（95％CI：67.5-83.3％），特异性为87.9。 ％（95％CI：79.0-93.5％）。良性息肉组与正常对照组的阳性检出率无显着性差异（p> 0.01），而AA和CRC组的阳性检出率明显高于正常个体组（p <0.001）。结论通过甲基化SFRP2和甲基化SDC2的联合测试（即所谓的SpecColon测试）对AA和早期CRC的敏感性，单独使用任何一种生物标志物都可以改善其特异性，而对特异性没有显着影响。它有可能成为早期CRC筛查的强大，便捷和高效的筛查工具。