KRT19 and head and neck squamous cell carcinoma: More recently, Tao et al (2006) report a real-time RT-PCR assay analysing CK19 mRNA level as a sensitive and reliable method for the detection of carcinomatous HNSCC cells in lymph nodes and increased CK19 expression has been reported to be associated with local failure and distant metastasis in HNSCC [21,22].