RFC4 and head and neck squamous cell carcinoma: RFC4 has been reported to be overexpressed in a variety of malignancies, including prostate cancer, cervical cancer, colorectal cancer, and head and neck squamous cell carcinoma (Slebos et al., 2006; Narayan et al., 2007; Erdogan et al., 2009; Kang et al., 2009).