AREG and head and neck squamous cell carcinoma: Although AREG was first described to inhibit growth of aggressive carcinoma cell lines [10], it is now defined as an oncogenic factor as it is up-regulated and related to poor prognosis in a wide variety of carcinomas, including ovarian, pancreatic, colorectal, breast, pulmonary, bronchial and bladder carcinomas [11], but its role in HNSCC remains controversial.