TKT and breast cancer: To validate the identified BL2-specific TK genes, we performed a comparative analysis using RNA expression data from TGCA and two additional TNBC datasets, including The Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) (119 BL1 and 63 BL2 patients) [31] and MET500 (11 BL1 and 10 BL2 patients) [32].