CD44 and oral cavity squamous cell carcinoma: Rajarajan et al.[54] found that the mRNA level of CD44 was significantly increased in oral squamous cell carcinomas; in addition, Lin et al.[55] revealed the CD44 mRNA levels in the peripheral blood of patients with locally advanced oral or oropharynx cancer were much higher than in healthy people, and a high CD44 mRNA level was significantly related to poor prognosis.