TP53 and neoplasm: Hence, dysregulated (i.e., decreased or overexpressed) expression or complete loss of tumor suppressor proteins p16INK4a, p21WAF1/Cip1 and p53 are often correlated with increasing grade of malignancy and tumor progression, and associated with a negative prognostic outcome [139, 140, 158, 170, 187, 205–207, 213, 214, 236] (Table 1) (Fig. 2B).