ERBB2 and gastric cancer: A retrospective study that included 129 patients with HER2-positive gastric cancer treated with first-line trastuzumab-based regimens, indicates that patients with loss of PTEN expression have a significantly shortened median PFS (4.5 vs. 12.4 months) and OS (12.3 vs. 28.9 months) compared with those with intact PTEN expression (15).