Purpose: In the search for a prognostic discriminant, Ki67 immunoreactivity of colorectal carcinoma was used to see whether this marker correlated with clinical and pathologic parameters and the ultimate prognosis of the patient.
Methods: Fresh specimens from 30 surgically resected adenocarcinomas were obtained and frozen in liquid nitrogen. Slides were immunohistochemically stained with Ki67. Ten randomly chosen fields were examined, and 1,000 nuclei per specimen were counted. The percent positive stained nuclei determined the Ki67 score. Correlation was made with the parameters of Dukes stage, location within the colon, size of malignancy, gender, age, and survival.
Results: There was a positive correlation of the Ki67 score for patients with metastatic disease, but no correlation was found to Dukes B and C cases. There was no correlation between Ki67 immunoreactivity and size or location of lesion, patient's age, patient's gender, or whether patient died of disease or developed a recurrence compared with those who survived five years disease-free.
Conclusion: Ki67 immunoreactivity could not be correlated with clinical and pathologic parameters except for metastatic disease in this study and was of limited use as a prognostic discriminant.