SP3 and endometrial serous adenocarcinoma: In another primary uterine and ovarian serous carcinoma study, HER2 expression using both ICD (CB11) and ECD (SP3) antibodies was higher in uterine serous carcinoma than in ovarian serous carcinoma, while high ICD staining with low ECD staining was seen in 8% (6/75) of uterine serous carcinoma cases and 42% (29/69) of ovarian serous carcinoma cases [7].