The DEGs mainly included those that respond to immune stimulates, such as MHC class molecules, CD74, IDO1, and ISG15, suggesting a close interaction between malignant and immune cells in the TME in this patient (SCLC-P2) (Fig. 3b, Supplementary Fig. S3b and Supplementary Table S3). Here, HLA-C is linked to small cell lung carcinoma.