Department of Breast and Endocrine Surgery, Graduate School of Medical Science, Kumamoto University, Kumamoto 860-8556, Japan.
Department of Molecular-Targeting Therapy for Breast Cancer, Kumamoto University Hospital, Kumamoto 860-8556, Japan.
Cancer Biomark. 2018;22(2):345-350. doi: 10.3233/CBM-171161.
Plasma and serum cell-free DNA (cfDNA) are useful sources of tumor DNA, but comparative investigations of the tumor mutational status between them are rare.
we performed droplet digital PCR assay for representative hotspot mutations in metastatic breast cancer (MBC) (ESR1 and PIK3CA) in serum and plasma cfDNA concurrently extracted from the blood of 33 estrogen receptor-positive MBC patients.
ESR1 mutations in plasma cfDNA were found in 7 of the 33 patients; ESR1 mutations in serum cfDNA were detected in only one out of 7 patients with ESR1 mutations in plasma cfDNA. PIK3CA exon 9 and exon 20 mutations in plasma cfDNA were found in 3 and 7 out of the 33 patients, respectively; PIK3CA exon 9 mutations in serum cfDNA were detected in 2 out of 3 patients with PIK3CA exon 9 mutations in plasma cfDNA; PIK3CA exon 20 mutations in serum cfDNA were detected in 2 out of 7 patients with PIK3CA exon 20 mutations in plasma cfDNA.
Here we show the higher frequency of ESR1 and PIK3CA mutations in the plasma than in the serum in 33 MBC patients; therefore, serum samples should not be considered the preferred source of cfDNA.
血浆和血清无细胞 DNA（cfDNA）是肿瘤 DNA 的有用来源，但它们之间肿瘤突变状态的比较研究很少。
我们同时对 33 例雌激素受体阳性转移性乳腺癌（MBC）患者的血液中同时提取的血清和血浆 cfDNA 中的代表性热点突变（ESR1 和 PIK3CA）进行了液滴数字 PCR 检测。
在 33 例患者中，有 7 例患者的血浆 cfDNA 中存在 ESR1 突变；在 7 例血浆 cfDNA 中存在 ESR1 突变的患者中，仅 1 例患者的血清 cfDNA 中存在 ESR1 突变。33 例患者中，有 3 例和 7 例分别在血浆 cfDNA 中发现 PIK3CA 外显子 9 和外显子 20 突变；在 3 例血浆 cfDNA 中存在 PIK3CA 外显子 9 突变的患者中，有 2 例患者的血清 cfDNA 中检测到 PIK3CA 外显子 9 突变；在 7 例血浆 cfDNA 中存在 PIK3CA 外显子 20 突变的患者中，有 2 例患者的血清 cfDNA 中检测到 PIK3CA 外显子 20 突变。
我们在此展示了 33 例 MBC 患者中血浆中 ESR1 和 PIK3CA 突变的频率高于血清，因此，血清样本不应被视为 cfDNA 的首选来源。
