ERBB2 and head and neck squamous cell carcinoma: Another reason for controversial results in different studies might be due to use of different immunohistochemical methods (direct, indirect), type of antibody (clone CerbB2, CB11, ICR1b, polyclonal DAKO, monoclonal zymed), no specific criteria for positive staining of HER2/neu protein (membrane and/ or cytoplasmic) and/or using different techniques (immunosorbent assay, radioimmunoassay, IHC) or the different locations of the lesions and sex of patients with HNSCC.