Transformation to large cell neuroendocrine carcinoma as acquired resistance mechanism of EGFR tyrosine kinase inhibitor

This case highlights acquisition of EGFR-TKI resistance by transformation to LCNEC, not SCLC. Loss of EGFR and Rb expression in the LCNEC suggests the same mechanism as transformation to SCLC. Further study is needed to elucidate this mechanism, especially regarding the similarities and differences to SCLC.