TP53 and neoplasm: IHC staining patterns of p53 were classified into five categories: (1) nuclear overexpression, characterized by strong and diffuse nuclear staining in at least 80% of tumour cells (Figure 1A); (2) complete absence of staining (null pattern; Figure 1B); (3) wildtype, identified by a mix of positive and negative cells at varying intensities, constituting less than 80% of tumour cells (Figure 1C); (4) cytoplasmic expression; and (5) subclonal expression.