ACTR2 and gliosarcoma: Many cancers, including HNSCC, oral squamous cell carcinoma, lung squamous cell carcinoma, gliosarcoma, breast cancer, colorectal cancer, and melanoma, are linked to amplification of the 11q13 segment on chromosome 11 (which includes the CTTN gene) and cortactin overexpression.[13] Cortactin is a filamentous (F) actin-binding and actin 2/3 (Arp2/3) complex-activating protein with an N-terminal acidic region (NTA) that binds and activates the Arp2/3 complex.