OBJECTIVE: Several recent studies have focused on human endogenous retroviruses (HERVs). HERVs entered the human genome millions of years ago and are associated with various diseases including cancer and immune regulation. Among these, the HERV-K family exhibits the highest transcriptional activity. However, little is known about the expression of HERVs in acute myeloid leukemia (AML) and their potential as biomarkers or therapeutic targets. This study primarily investigated the role of HERV-K102 in AML development and explored the underlying mechanisms. METHODS: The expression profiles of HERV K102 in AML and normal samples were analyzed using The Cancer Genome Atlas (TCGA) database and AML cell lines. Knockout models were generated using CRISPR-Cas9-mediated deletion of the HERV-K102 envelope (K-Env). Cell viability and pyroptosis rates were measured using the MTT assay and flow cytometry, respectively. Transcriptome analysis was performed to identify differentially expressed genes and related pathways. Pyroptosis markers were detected using qRT-PCR and western blotting. The role of HERV-K102 in AML was validated using an inducible knockout xenograft tumor model. RESULTS: HERV-K102 was aberrantly activated and highly expressed in AML cells. K-Env depletion inhibited AML cell proliferation and promoted apoptosis. Furthermore, K-Env knockout induced pyroptosis, as indicated by increased lactate dehydrogenase (LDH) release and enhanced cleavage of caspase-1 and gasdermin D (GSDMD). Transcriptomic and functional analyses demonstrated that this process is mediated by S100A9 upregulation and activation of the NOD-like receptor protein 3 (NLRP3) inflammasome pathway. CONCLUSION: Our findings suggest that HERV-K102 Env may play an important role in AML pathogenesis and represents a novel diagnostic and therapeutic target.