Transcriptomic heterogeneity of EGFR-mutant non-small cell lung cancer evolution towards small cell lung cancer

Histological transformation from epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) to small cell lung cancer (SCLC) is the major resistance mechanism of EGFR tyrosine kinase inhibitors (TKIs). In our analysis of 59 regions of interest from EGFR-mutant NSCLC or combined SCLC/NSCLC tumors, we compared the transcriptomic profiles before and after transformation. In this study, clinical specimens from 10 patients were selected for spatial and whole transcriptome analysis. To decipher the molecular changes that occur during transformation, we conducted DEG analysis by categorizing the patients into NSCLC and SCLC groups, irrespective of their EGFR-TKI treatment state. This study was approved by the Institutional Review Board of the Seoul National University Hospita and performed in accordance with the Declaration of Helsinki.