在7月出版的爱思唯尔期刊《美国外科医师学会杂志》（Journal of The American College of Surgeons）上，一项新研究的结果证实血浆DNA浓度的上升是食道癌复发的可靠标志。研究同时还指出，对于大多数患者而言，其血浆中DNA浓度的增加先于其它临床证据发生。
食道癌是引起世界范围内患者死亡的主要癌症之一，它一般在晚期阶段才能得到诊断。因此，一种准确的检测食道癌转移的标志物能帮助医生更好的选择接受治疗的患者，预测患者接受治疗之后的反应，以及在癌症复发时采取必要的措施。尽管科学家已经知道癌胚抗原（carcinoembryonic antigen CEA）和血浆DNA浓度会在食道癌患者体内增加，并且浓度在发生转移情况下变得更高，但是这些标志物在复发诊断过程中的灵敏性和特异性并未得到确定。
加州大学洛杉矶分校医学院外科系助理教授Farzaneh Banki表示：“不通过手术诊断食道癌转移以及在术后诊断癌症的复发一直是我们面临的一个挑战，这是由于食道癌的临床分期很困难，而目前的扫描技术有限。我们的研究结果表明，测量DNA含量能有助于诊断和预测食道癌的复发。”
研究分析了血浆DNA作为食道癌术前转移和术后残留/复发的标志物的灵敏性和特异性。科学家测量了45位食道癌病人和44位健康志愿者体内血浆DNA的含量，此外，研究小组还测量了31位患者的血清CEA浓度。
结果发现，相比CEA，血浆DNA在检测那些无法被外科手术去除的癌症方面灵敏度更好，血浆DNA的灵敏度为100%，CEA为40%。并且血浆DNA在检测食道癌复发方面也比CEA灵敏度高（分别为100%和33%）。所有癌症复发的患者血浆DNA浓度都有所上升，而且血浆DNA正常的患者全都没有复发。对于67%的复发患者而言，其血浆DNA浓度上升早于临床证据出现，而对于CEA而言，这一数字仅有17%。
科学家因此建议，血浆DNA对于诊断复发病人有重要价值，而正常的CEA值则需要小心对待，因为它并未完全排除疾病复发的可能。最后研究人员表示，还需要更多患者和更长的追踪研究来确认以上发现。（生物谷Bioon.com）
生物谷推荐原始出处：
Journal of The American College of Surgeons，doi:10.1016/j.jamcollsurg.2008.01.004，Farzaneh Banki, Tom R. DeMeester
Plasma DNA Is More Reliable than Carcinoembryonic Antigen for Diagnosis of Recurrent Esophageal Cancer
Farzaneh Banki MDa, , Wael N. Yacoub MDa, Jeffrey A. Hagen MD, FACSa, Rodney J. Mason MD, PhD, FACSa, Shahin Ayazi MDa, Steven R. DeMeester MD, FACSa, John C. Lipham MD, FACSa, Kathleen Danenberg BScb, Peter Danenberg PhDb and Tom R. DeMeester MD, FACSa
Background
Carcinoembryonic antigen (CEA) and plasma DNA are known to be elevated in patients with esophageal cancer and are higher in patients with disseminated disease. The sensitivity and specificity of these markers in the diagnosis of recurrent esophageal cancer have not been compared.
Study Design
Plasma DNA was measured using polymerase chain reaction in 45 patients with esophageal cancer and 44 asymptomatic volunteers. The 95th percentile (19 ng /mL) in the volunteers was used to define normal. Thirty-nine patients had localized cancer and underwent resection, and six had disseminated disease at operation. Plasma DNA was measured preoperatively in all patients, with serum CEA measured in 31. Plasma DNA was measured sequentially during followup in 21 patients, including 7 who developed recurrence. CEA was measured in 14 of 21 patients who had sequential plasma DNA measured and in 6 of 7 patients with recurrence. CEA levels greater than 5.0 ng/mL were used as cut-off.
Results
Plasma DNA was more sensitive than CEA for detecting unresectable esophageal cancer (100% versus 40%), but it had a lower specificity (22% versus 89%).The positive predictive value (19% versus 40%) and negative predictive value (100% versus 89%) were similar for plasma DNA and serum CEA, respectively.
Plasma DNA was also more sensitive than CEA in detecting recurrent esophageal cancer (100% versus 33%). The specificity and positive predictive values were 100% for both tests, but the negative predictive values were higher for plasma DNA. Plasma DNA rose before there was clinical evidence of recurrence in 67% compared with only 17% for CEA.
Conclusions
Elevated plasma DNA is an extremely reliable indicator of the presence of recurrent disease, and, in the majority of patients, it rises before clinical evidence of recurrence. In contrast, a normal CEA should be interpreted cautiously, because it does not exclude recurrent disease.
