Venetis Venetis K K Crimini Crimini E E Sajjadi Sajjadi E E HER2 low, ultra-low, and novel complementary biomarkers: expanding the spectrum of HER2 positivity in breast cancer HER2 low, ultra-low, and novel complementary biomarkers: expanding the spectrum of HER2 positivity in breast cancer Front Mol Biosci Front Mol Biosci 2022 2022 15 15 9 9 834651 834651 10.3389/fmolb.2022.834651 10.3389/fmolb.2022.834651. This evidence concerns the gene ERBB2 and breast carcinoma.