SDC1 and breast cancer: Conversely, in HER2 + breast cancer, SDC1 expression in stromal cells was significantly associated with improved OS [HR: 0.14 (0.02, 0.85), P = 0.0326], but not found in Luminal or triple-negative subtypes [HR: 1.00 (0.57, 1.73), P = 0.9861 and HR: 0.46 (0.17, 1.30), P = 0.1449, respectively], as detailed in Table 4.