CD44 and neoplasm: Furthermore, CD44, a marker for cells with tumor initiating potential, was identified as a BTNBC marker in both PDX (log2FC = 2.14, FDR = 5.91E–04) and cell line (log2FC = 2.58, p = 8.66E–03) but not in clinical (log2FC = 0.06, FDR = 0.79) datasets.