Objective: To find out whether p53 overexpression correlates with metastatic potential and other adverse prognostic factors in early invasive colorectal carcinoma and whether measurement of the expression of p53 protein could be helpful in the choice of treatment (endoscopic/local or radical resection).
Design: Retrospective study.
Setting: University hospital, Japan.
Subjects: Overexpression of p53 protein in the primary tumour was examined immunohistochemically in 50 patients with early invasive colorectal cancer.
Main outcome measures: Differences in p53 overexpression between subgroups.
Results: Abnormal accumulation of 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 superficial (type II) lesions compared with 10 (28%) of 36 protruding (type I) ones (p = 0.009) and in 12 (57%) of 21 moderately differentiated adenocarcinomas compared with 8 (28%) of 29 well-differentiated adenocarcinomas (p = 0.045). There was no significant correlation between p53 overexpression and the depth of tumour invasion or angiolymphatic involvement. The p53-positive metastasising tumours had features that corresponded to those of early carcinoma arising de novo.
Conclusion: Our results seem to support the postulate that p53 overexpression in early invasive colorectal carcinomas is associated with an increase in their metastatic potential.