Abstract
BACKGROUND: Small cell lung cancer (SCLC) exhibits a pronounced tendency for metastasis and relapse, and the acquisition of resistance to chemotherapy and radiotherapy, leading to complexity in treatment outcomes. It is crucial to tackle these challenges by advancing targeted therapeutic approaches in ongoing research endeavors. Variant RET fusions have been reported in several solid tumors, but are rarely reported in SCLC. CASE SUMMARY: We present the first case of a KIF5B-RET fusion in a 65-year-old male patient with SCLC. To date, the patient has received the 4th line chemotherapy with anlotinib for one year and has shown a sustained favorable partial response. According to the results of next generation sequencing, this SCLC patient harbors the KIF5B-RET fusion, suggesting that RET fusion could serve as a promising molecular target for SCLC treatment. Next-generation sequencing (NGS) plays a critical role in comprehensively assessing the genotype and phenotype of cancer. CONCLUSION: NGS can provide SCLC patients with personalized and targeted therapy options, thereby improving their likelihood of survival.