IRX1 and head and neck squamous cell carcinoma: Although normal salivary methylation rate was observed as high, IRX1 methylation values were <1% in normal salivary rinses and were mostly (8/14, 57%) between 0.1 and 10% in normal mucosal samples indicating a very strong marker which may define HNSCC tumor tissues as a potential biomarker (Fig. 1).