STUB1 and myeloid neoplasm: Accordingly, a diagnosis of CHIP requires detection of ≥1 somatic mutation with a VAF ≥ 2% in blood or BM cells (≥4% for X-linked gene mutations in men) based on a specific list of mostly myeloid neoplasm-associated driver genes, as well as the absence of unexplained cytopenias or any defined myeloid neoplasm.