Some studies have shown that patients with EGFR mutations had a clinical effective rate of 54% to platinum-etoposide after SCLC transformation, and the median estimated PFS was 3.4 months, but there was no response to checkpoint inhibitors, and the longest progression time was only 9 weeks (8); At the same time, some studies have shown that for the NSCLC patients with RET rearrangement, the effect of RET TKI treatment after transformation to SCLC may be poor (27, 28). The gene discussed is RET; the disease is non-small cell lung carcinoma.