Fig. 1: HER2 immunohistochemical staining in uterine serous carcinoma.

A Score of 0 (negative), with faint staining in ≤10% of tumor cells. B Score of 1+ (negative), in which there is faint, incomplete membranous staining in >10% of tumor cells. C Score of 2+ (equivocal), with strong, circumferential staining in ≤10% of tumor cells. D Score of 3+ (positive), with circumferential, complete membrane staining that is intense and >10% of tumor cells.