Division of Experimental Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota 55906, USA.
Clin Cancer Res. 2011 Nov 15;17(22):7183-93. doi: 10.1158/1078-0432.CCR-11-0981. Epub 2011 Oct 5.
To investigate the associations between baseline and posttreatment circulating tumor cell (CTC) gene expression and outcome of patients enrolled in four North Central Cancer Treatment Group metastatic breast cancer (MBC) trials in which specimens were shipped (at 4°C) from community-based sites to a reference laboratory (Mayo Clinic, Rochester, MN).
Blood was collected at treating sites from MBC patients before (baseline), during, and at the end of treatment with erlotinib + gemcitabine (N0234), sorafenib (N0336), irinotecan + cetuximab (N0436), or paclitaxel-poliglumex + capecitabine (N0437). CTCs from 10 mL of EDTA blood were enriched with CD45 depletion, 24 to 30 hours postblood collection. Reverse transcription/quantitative PCR was used to determine cytokeratin-19 (CK19) and mammaglobin (MGB1) mRNA levels in CTCs from up to 13 (N0234), 16 (N0336), 18 (N0436), and 39 (N0437) patients. The gene expressions were normalized to β(2)-microglobulin and calibrated to healthy blood using the 2(-ΔΔCq) algorithm; positivity was defined as 2 or more.
CK19+mRNA cells were detected in 56% to 75% and MGB1+mRNA cells in 23% to 38% of 86 patients at baseline. CK19+mRNA cells were detected in 30% to 67% and MGB1+mRNA cells in 14% to 64% of 110 postbaseline serial samples. The presence of baseline CK19+mRNA cells (P = 0.01) but not MGB1+mRNA cells (P = 0.14) was significantly associated with shorter overall survival. A decrease in MGB1+mRNA levels (baseline-week 8) seemed to be associated with clinical response (P = 0.05).
CTC gene expression analysis conducted by a reference laboratory is feasible when blood is collected from treating sites and processed 24 to 30 hours postcollection. The presence of baseline CK19+mRNA CTCs was associated with poor prognosis; a decrease in MGB1+mRNA CTCs may help predict response to therapy of MBC patients.
研究四项北中央癌症治疗组转移性乳腺癌（MBC）试验中基线和治疗后循环肿瘤细胞（CTC）基因表达与患者结局的相关性，这些试验的标本是从社区站点运送到参考实验室（明尼苏达州罗切斯特市的梅奥诊所）。
在接受厄洛替尼+吉西他滨（N0234）、索拉非尼（N0336）、伊立替康+西妥昔单抗（N0436）或紫杉醇聚谷氨酸+卡培他滨（N0437）治疗的 MBC 患者治疗前（基线）、治疗期间和治疗结束时，从治疗部位采集 MBC 患者的血液。在血液采集后 24 至 30 小时，使用 CD45 耗尽法从 10 毫升 EDTA 血液中富集 CTC。采用逆转录/定量 PCR 检测多达 13 例（N0234）、16 例（N0336）、18 例（N0436）和 39 例（N0437）患者 CTC 中的细胞角蛋白 19（CK19）和乳球蛋白（MGB1）mRNA 水平。使用 2(-ΔΔCq)算法将基因表达标准化为β(2)-微球蛋白，并使用健康血液进行校准；阳性定义为 2 个或更多。
86 例患者中有 56%至 75%在基线时检测到 CK19+mRNA 细胞，23%至 38%检测到 MGB1+mRNA 细胞。110 例基线后系列样本中有 30%至 67%检测到 CK19+mRNA 细胞，14%至 64%检测到 MGB1+mRNA 细胞。基线时存在 CK19+mRNA 细胞（P = 0.01）但不存在 MGB1+mRNA 细胞（P = 0.14）与总生存期较短显著相关。MGB1+mRNA 水平的降低（基线-第 8 周）似乎与临床反应相关（P = 0.05）。
当从治疗部位采集血液并在采集后 24 至 30 小时进行处理时，由参考实验室进行 CTC 基因表达分析是可行的。基线时存在 CK19+mRNA CTC 与预后不良相关；MGB1+mRNA CTC 的减少可能有助于预测 MBC 患者对治疗的反应。
