IL34 and neoplasm: Our study revealed the presence of interleukin-34 (IL-34), HLA class II histocompatibility antigen, DM alpha chain (HLA-DMA), and HLA class II histocompatibility antigen, DO beta chain (HLA-DOB) in serum exosomes of NSCLC patients, which, according to TIMER2.0 analysis, have a significant impact on tumor infiltration by CAFs and M2 macrophages contributing to tumor progression.