PTPRF and breast cancer: Human liprin-α1 is encoded by the gene PPFIA1 (PTPRF [Protein Tyrosine Phosphatase Receptor Type F polypeptide] Interacting Protein Alpha 1), which maps to the 11q13 chromosomal region that is often amplified in multiple cancer types, such as in head and neck squamous cell carcinoma (HNSCC), breast cancer and esophageal carcinoma [54–61].