TP53 and cancer: Our results are also supported by multiple recent studies of various non-salivary malignancies which demonstrated that high scores of Ki67 and p53 staining predict a higher tumourogenic grade, a higher rate of metastasis spread and a poorer prognosis, whereas low scores of Ki67 and p53 are associated with prognostically better histopathologic features (Saleh et al, 2000; Ben-Izhak et al, 2001, 2002, 2003; Jalava et al, 2006).