ERBB2 and neoplasm: Furthermore, except for the case 2 and case 3, five cases (case 5, case 6, case 7, case 9, and case 11) showed an obvious increasing trend of plasma HER2 ratio at least 2 months before the time of tumor progression, which was approximately 1.7-2 times higher than the cut-off value (Table 2 and Figure 3).