KMT5B and squamous cell carcinoma: To further elucidate the importance of protein methyltransferase SUV420H1 in human cancer, we examined the expression profile of SUV420H1 by quantitative real-time PCR (qRT-PCR) in 11 squamous cell carcinoma cell lines of the head and neck (SCCHN), and identified three SCCHN cell lines that expressed significantly higher levels of SUV420H1 mRNA compared to normal keratinocytes (Figure 2A).