TP53 and Fibroadenoma: In contrast, whereas fibroadenomas lack copy number changes, most PT show chromosomal instability, such as recurrent loss on chromosome 1q, 4p, 10, 13q, 15q, 16, 17p, 19, and X, involving loss of loci of TP53 and CDH1, and recurrent copy number gains on 1q, 2p, 3q, 7p, 8q, 16q, and 20 [8].