When considering differences in histological types of cancers, high levels of HER2 were significantly associated with a poorer DFS/PFS of unclassified ovarian cancer patients (n = 11, HR = 1.34, 95% CI = 1.08 to 1.67, H2 = 1.1; I2 = 14.3%, 95% CI = 0% to 55%), but not in serous ovarian cancer patients (n = 3, HR = 1.03, 95% CI = 0.6 to 1.75, H2 = 1.5; I2 = 56%, 95% CI = 0% to 87%) (Fig 5). This evidence concerns the gene ERBB2 and cancer.