Chen M, et al. – This paper entailed the formulation and validation of fluorescence in situ hybridization assay for JAK2 and PD–L1 amplification in triple negative breast cancer tumor patients. It was observed that the novel array–based comparative genomic hybridization assay for detection of chromosome 9p24.1 exhibited a strong association with the detection of copy–number gain by array–based comparative genomic hybridization. In triple negative breast cancer, this biomarker could detect a relevant subset of patients for targeted molecular therapies.