Mutational Analysis of OCT4+ and OCT4− Circulating Tumour Cells by Single Cell Whole Exome Sequencing in Stage I Non-Small Cell Lung Cancer Patients

Circulating tumour cells (CTCs) were enriched in the peripheral blood of four patients with Stage I non-small cell lung cancer (NSCLC). Octamer-binding transcription factor-4 positive (OCT4+) and negative (OCT4−) CTCs were identified and captured by interphase fluorescence in situ hybridisation (iFISH). Single cell whole exome sequencing (WES) was performed and the corresponding bioinformatics data were analysed. OCT4+ cells were successfully detected in peripheral blood collected from all four Stage I lung cancer patients. Moreover, the tumour mutational burden (TMB) values observed for OCT4+ samples from the same patients were slightly smaller than those of the OCT4− samples; the difference was not statistically significant (P> 0.05). Thirteen and six characteristic mutations were found in negative samples and positive samples, respectively. The findings indicate that this methodology provides a potential diagnostic index for the early detection of NSCLC.