MYB/CEP6 dual-color probe aims to detect the deletion of the MYB gene at chromosome 6q23.3. The MYB gene encodes a transcript that is expressed primarily in early lymphocytes and bone marrow cells. In different types of lymphoid tumors, 6q aberration is the most common chromosomal variation, and several major deletion regions are on the long arm of chromosome 6. One is 6q23. 3-10% of CLL (chronic lymphocytic leukemia) have chromosome structural aberrations at 6q. The absence of MYB is often accompanied by a secondary change. Because traditional cytogenetic methods are not effective in detecting changes in CLL, the use of fluorescence in situ hybridization (FISH) molecular cytogenetic research method can diagnose and prognose CLL.