Chronic neutrophilic leukemia CSF3R mutation The CSF3R gene (granulocyte colony-stimulating factor receptor, also known as G-CSFR) is a member of the hematopoietic cell receptor superfamily, and is located on chromosome 1p34.3. Although it has no endogenous tyrosine kinase activity, it can change its conformation through ligand binding to stimulate a variety of tyrosine kinases related to its cellular activity range, including JAKs, SRC kinase family, SYK, TNK, etc. Important channel systems include signal transduction transcription STAT, phosphatidylinositol kinase PI3-K-AKT, and RAS-MAPK. RAS-MAPK and so on [18, 19], which shows that its mechanism of action is very complex. As recent findings, mutations in CSF3R are associated with many diseases, the vast majority of which are associated with myeloid systemic diseases, such as hereditary neutropenia (SCN), MDS, AML, and CNL. There are multiple mutations in the genetically encoded G-CSFR, and at least 18 mutations in CSF3R are known to be involved, and different mutation patterns are associated with different diseases, such as mutations in p.Thr595Ile (p.Thr618Ile) are associated with CNL [18], and Maxson et al [20] studied the expression of CSF3R in malignant hematological tumors and found that CSF3R mutations were present in 16 (59%) of 27 patients with CNL or aCML; 3 (1%) of 292 AML and 8 T-cell and 41 B-cell ALL were negative. a study by Gotlib et al [4] showed that 8/9 (89%) of CNL and 8/20 (40%) of aCML patients were detected with CSF3R mutated genes. pardanani et al [19] tested 35 cases of clinically diagnosed CNL, 19 cases of aCML, 94 cases of CMML and 76 cases of PMF for CSF3R mutated genes, resulting in the detection of 14 CSF3R mutated genes in 13 cases. The diagnosis of these cases was then determined according to WHO criteria, resulting in 12 cases of CNL meeting WHO diagnostic criteria (unrelated to monoclonal globulin and lymphoma), 6 cases of monoclonal globulin (MG)-associated CNL, 17 cases of suspected CNL but not meeting WHO criteria; 9 cases of aCML meeting WHO criteria and 10 cases of aCML not meeting WHO criteria (of which identified as BCR/ABL1-positive CML in 2 cases, CMML in 3 cases, MDS/MPN-U in 2 cases, PMF in 1 case, MPN-U in 1 case, and systemic histiocyte-associated MDS/MPN-U in 1 case); a total of 170 other cases of CMML and PMF met WHO diagnostic criteria. 14 cases of CSF3R mutation in 13 cases were 12 cases of WHO diagnostic criteria for The positive rate of CSF3R mutations in CNL was 100%, with CSF3RT618I being the most common in 10 cases, all of which met the WHO diagnostic criteria for CNL (83% of CNL meeting WHO criteria), and the other 3 cases showed CSF3RI598I or CSF3RM696T mutations. These results suggest that the CSF3RT618I gene is a highly specific and sensitive molecular marker for CNL.