DOES P53 OVEREXPRESSION CAUSE METASTASES IN EARLY INVASIVE COLORECTALADENOCARCINOMA

Objective: To find out whether p53 overexpression correlates with meta static potential and other adverse prognostic factors in early invasiv e colorectal carcinoma and whether measurement of the expression of p5 3 protein could be helpful in the choice of treatment (endoscopic/loca l or radical resection). Design: Retrospective study. Setting: Univers ity hospital, Japan. Subjects: Overexpression of p53 protein in the pr imary tumour was examined immunohistochemically in 50 patients with ea rly invasive colorectal cancer. Main outcome measures: Differences in p53 overexpression between subgroups. Results: Abnormal accumulation o f nuclear p53 was detected in the primary tumour of 20 patients (40%) with early invasive colorectal cancer. We found p53-positive cells in 7 (78%) of 9 that had metastasised to regional lymph nodes or distant organs, or both, and in 13 (32%) of 41 that had not metastasised (p = 0.02). p53 Immunoreactivity was also present in 10 (71%) of 14 superfi cial (type II) lesions compared with 10 (28%) of 36 protruding (type I ) ones (p = 0.009) and in 12 (57%) of 21 moderately differentiated ade nocarcinomas compared with 8 (28%) of 29 well-differentiated adenocarc inomas (p = 0.045). There was no significant correlation between p53 o verexpression and the depth of tumour invasion or angiolymphatic invol vement. The p53-positive metastasising tumours had features that corre sponded to those of early carcinoma arising de novo. Conclusion: Our r esults seem to support the postulate that p53 overexpression in early invasive colorectal carcinomas is associated with an increase in their metastatic potential.