It can be used as a control for the detection of related genes on chromosome 17, or independently for the detection of chromosome 17 count, which can detect chromosome abnormalities in general. Polymer and monomer of chromosome 17 are important factors affecting the results of FISH test of HER-2 gene. Adiploid of chromosome 17 leads to some differences in clinicopathological characteristics of breast cancer, especially polymer chromosome 17, which may have important relationship with breast cancer treatment and prognosis.