Prognostic significance of p53 nuclear and cytoplasmic overexpression in right and left colorectal adenocarcinomas

The prognostic significance of nuclear and cytoplasmic p53 protein, detected immunocytochemically using CM1 and PAb 1801 antibodies, was evaluated in right-sided and left-sided colorectal adenocarcinomas from 293 patients. CM1 nuclear and cytoplasmic p53 accumulation occurred in 38 and 25% of cases, respectively. PAb 1801 nuclear staining occurred in 18%, with no cytoplasmic staining. CM1 expression either in the nucleus or in the cytoplasm was positively related to PAb 1801 expression (P < 0.001 and P = 0.009, respectively). The incidence of CM1 nuclear and cytoplasmic expression was more frequent in right-sided tumours (P = 0.023 and P = 0.034, respectively), while PAb 1801 nuclear staining was more common in left-sided tumours (P = 0.011). In survival analyses, CM1 nuclear overexpression in the right-sided tumours (P = 0.016) and CM1 cytoplasmic overexpression in left-sided tumours (P = 0.04) were prognostic indicators, independent of Dukes' stage, DNA ploidy, PAb 1801 expression and each other. Further analysis showed that the prognostic value of CM1 nuclear expression was greater in right-sided tumours than in left-sided tumours (P = 0.018). The nuclear and cytoplasmic p53 protein detected with CM1 and PAb 1801 may play different roles in tumour progression and provide prognostic indicators for right- and left-sided colorectal tumours.