ERBB2 and cancer: Eventhough it is reported that Smurf2 is highly expressed in breast cancer [14], clinical information regarding the frequency and level of Smurf2 and CNKSR2 expression in breast cancer is incomplete, especially as regards differentiating the importance of Smurf2 and CNKSR2 expression in breast cancer subtypes with increasing tumorigenic potential including normal, usual hyperplasia, fibrocystic changes, fibroadenoma, carcinoma-in-situ (DCIS), and invasive ductal carcinoma (IDC) and its association with the ER, PR, and HER2 status of the breast tissue samples.