A new isolation method for peripheral blood circulating solid tumor cells with EpCAM antibody linked nanobeads / 中华检验医学杂志

ABSTRACT

Objective To establish an isolation method for solid GTC in peripheral blood using EpCAM antibody-linked nanobeads and evaluate the sensitivity of the method and its application significance. Methods Five, ten, twenty, fifty and one hundred MCF7 (breast cancer), KYSE70 (esophageal cancer), BxPC-3 (pancreatic cancer) and 9811P (stomach cancer) cells were added into 7. 5 ml erythrocyte lysed peripheral blood obtained from healthy volunteers respectively. EpCAM antibodylinked nanobeads were used to enrich cancer cells. The recovery rates of the in vitro added cancer cells were evaluated by fluorescence microscopy. Then, the untreated thirty cases of esophageal cancer (six cases at stage Ⅰ and Ⅱ, twenty-four cases at stage Ⅲ and Ⅳ), thirty-five cases of breast cancer (fifteen cases at stage Ⅰ and Ⅱ , twenty cases at stage Ⅲ and Ⅳ), thirty cases of pancreatic cancer (five cases at stage Ⅰ and Ⅱ , twenty-five cases at stage Ⅲ and Ⅳ), thirty-three gastric cancer (thirteen cases for stage Ⅰ and Ⅱ ,twenty cases at stage Ⅲ and Ⅳ) were enrolled to enrich the peripheral blood CTC. Thirty healthy volunteers and thirty gastritis patients served as two groups of control. Meanwhile the enriched CTC was identified by IF and HE staining. FISH was used to analyze the copy number of chromosome 8 and chromosome 20 in two hundred esophageal cancer, breast cancer, pancreatic caner and gastric cancer CTC. Results After DAPI staining and mixing with 7.5 ml peripheral blood from healthy donors, the average cell recovery rates of KYSE70, MCF7, BxPC-3 and 9811P cells evaluated under fluorescence microscope were 87%, 87%, 86% and 88% (within group), and the recovery rates of 5 gradient dilution levels were 88%, 85%, 87%, 88% and 87% (intergroup). With a high sensitivity, this method was able to isolate one cancer cell in 107 white blood cells of peripheral blood. The positive rates of more than 2 CTC in the peripheral blood detected by this method were 50% (15/30) of esophageal cancer, 63% (22/35) of breast cancer, 70% (21/30) of pancreatic cancer and 61% (20/33) gastric cancer patients respectively,but no CTC was detected in the peripheral blood of healthy volunteers and gastritis patients (P = 0. 000).The aneusomy of chromosome 8 and chromosome 20 were found in 80% esophageal cancer, 75% breast cancer, 65% pancreatic cancer and 59% gastric cancer. Conclusions The CTC isolation technique with EpCAM antibody-linked nanobeads is sensitive and accurate. The aneusomy of chromosome 8 and 20 is frequent in CTC from esophageal cancer, breast cancer, pancreatic cancer and gastric cancer.