17p contains tumor suppressor genes such as TP53. Frequently, allelic losses of 17p coincide with mutations of TP53 located at 17p13. 1. In the absence of genetic alterations in TP53, however, breast cancers and other solid tumors exhibit genetic alterations in the telomeric region, including the 17p13. 3 locus [5–11]. This evidence concerns the gene TP53 and breast cancer.