An LOH study of 41 ADH samples at 15 genetic loci selected based on the locations of frequently inactivated tumor suppressor genes in IDC, such as TP53, RB1, and BRCA1, reported that 42% of “pure” ADH (without synchronous DCIS/IDC) showed LOH in at least one locus, suggesting that inactivation of these tumor suppressor genes might be an early neoplastic event and related to the subsequent development of IDC [45]. Here, AVP is linked to ductal breast carcinoma in situ.