Detection of free‐circulating tumor‐associated DNA in plasma of colorectal cancer patients and its association with prognosis

作者：Thierry Lecomte, Anne Katrin Berger, Franck Zinzindohoué, Stéphanie Micard, Bruno Landi, Hélène Blons, Philippe H. Beaune, Paul‐Henri Cugnenc, Pierre Laurent‐Puig · 发表于：International Journal of Cancer · 年份：2002 · DOI：10.1002/ijc.10526 · 被引用次数：300 · 研究领域：Cancer Genomics and Diagnostics、Genetic factors in colorectal cancer、Epigenetics and DNA Methylation

Tumor cells are characterized by specific genetic alterations. When such genetic alterations are identified in body fluid including plasma, regardless of the presence of detectable tumor cells, it shows the existence of free-circulating tumor-associated DNA. The objective of our study was to assess the prognostic value of free-circulating tumor-associated DNA in colorectal cancer patients' plasma. The first step of our work was to find common genetic alterations in tumors that would subsequently be used for plasma DNA screening. We focused on KRAS2 mutations in codons 12 and 13 by the mutant allele-specific amplification (MASA) method and p16 hypermethylation by the methylation-specific polymerase chain reaction (MSP) method. Patients with a tumor presenting either alteration were selected for plasma screening; 58 tumors were analyzed for KRAS2 mutations and tested for p16 gene promoter methylation. Survival and recurrence rates were assessed in patients with and without free-circulating tumor-associated DNA alterations in plasma. Of the 58 tumors analyzed, 39 (67%) demonstrated either one or both of the studied genetic alterations. Twenty-two (38%) were mutated at KRAS2, and an identical alteration was detected in 10 (45%) of the 22 corresponding plasma samples. Thirty-one (53%) had p16 gene promoter hypermethylation that could also be detected in the plasma in 21 cases (68%). Among the 39 patients who had one or the other alteration in tumor DNA, 37 had at least one reliabl...