PGR and cancer: In patients with triple-negative breast cancer (that is, cancers that were estrogen receptor-negative, progesterone receptor-negative and HER2-negative), the five-year OS rate (50%) was significantly lower in VEGFR-1-positive patients (n = 6) compared to that in VEGFR-1-negative patients (n = 55; 79.9%; P <0.05; Figure 4b).