TRIM24 and carcinosarcoma: We used RNA-Seq analysis of MpBC patient tumor biopsies, acquired at the time of enrollment in the clinical trial, to generate a human TRIM24 metaplastic breast cancer signature using the SIGNATURE system, as previously described41, and developed a heatmap representation of the TRIM24 metaplastic signature expressed by murine metaplastic carcinosarcoma (M) versus carcinoma tumors (C) (Fig. 6a and Supplementary Data 8).