fig3

Figure 3. Mechanisms of small cell transformation in the progression of ALK-targeted resistance in lung cancer. SCLC can originate from neuroendocrine cells, while adenocarcinoma typically arises from basal cells. Alveolar type II cells may serve as a potential origin for both SCLC and adenocarcinoma. During SCLC transformation, multiple genetic alterations and signaling pathway activations are involved, including RB1 and TP53 loss, mutations in genes such as NOTCH1 and PTEN, ALK-TKI resistance, and ALK rearrangements. Created in BioRender. Long, M. (2025). https://BioRender.com/ogqzb3a. SCLC: Small cell lung cancer; ALK-TKI: anaplastic lymphoma kinase tyrosine kinase inhibitor.