Intratumor Heterogeneity of EGFR Activating Mutations in Advanced NSCLC Patients at Single-Cell Level
Download as PDF
Introduction: Present study is to explore the controversial problem whether the intratumoral heterogeneity of EGFR activating mutation exists at the level of single cancer cells. Materials and Methods: Single H1975 cells harbored EGFR exon 21 L858R mutation were isolated by flow cytometry to assess the feasibility of single-cell analysis for EGFR exon 21 by nested polymerase chain reaction and derect sequence. Then, six patients diagnosed with lung adenocarcinoma whose fresh frozen specimens harbored EGFR exon 21 mutation tested by direct sequencing were chosen. All of them received gefitnib treatment and the PFS of three patients was longer than 12 months (Group A) while the PFS of other three patients was shorter than 6 months (Group B). By using the established method based on single H1975 cells, EGFR exon 21 mutational status was analyzed in single tumor cells which were captured from tumor sample by Laser Capture Microdissection. Results: A total of 104 individual H1975 cells were obtained. The amplification rate and allele drop-out rate were 96.2% and 7.0%, respectively. A total of 135 tumor cells from six patients’ samples were captured. The amplification rate of nested PCR was 84.3% (59/70) in Group A and 93.8% (61/65) in Group B (P=0.077). The mutational rate was 86.4% in Group A, which was significantly higher than the total mutational rate 68.9% in Group B (P=0.021).Conclusion: The intratumoral heterogeneity of EGFR activating mutation in lung adenocarcinoma does exist based on the analysis of single cancer cells.
Egfr, Nsclc, Intratumor Heterogeneity