The following key terms and their combinations were used: “antibody-drug conjugate,” “ADC,” “small cell lung cancer,” “SCLC,” “DLL3,” “B7-H3,” “TROP2,” “SEZ6,” “CD56,” “Rovalpituzumab Tesirine,” “DS-7300,” “Ifinatamab Deruxtecan,” “Sacituzumab Govitecan,” “clinical trial,” and “mechanism.” Inclusion criteria were: original research articles, clinical trials (any phase), meta-analyses and authoritative reviews; studies addressing ADC structure, mechanism, efficacy, safety or resistance in SCLC; and publications in English or with an English abstract. This evidence concerns the gene TACSTD2 and small cell lung carcinoma.