Expression of EGFR -mutant proteins and genomic evolution in EGFR -mutant transformed small cell lung cancer.

19del or L858R-mutant proteins could be constantly expressed, and EGFR pathway still existed in -mutant transformed SCLC/NEC with a common clonal origin from the baseline LUAD. Taking together, these molecular characteristics potentially favored clinical efficacy in transformed SCLC/NEC treated with the combo regimen.