Clinical Significance of PTEN Expression in Colorectal Cancer

ABSTRACT

PURPOSE: Tumor suppressor gene called PTEN has been localized to 10q23 in 1997 and its mutation has been implicated in some malignancies. Loss of the PTEN gene has been clinically associated with unfavorable histology and influencing tumor staging and recurrence in the determination of a prognosis in patients suffering from other cancers, its role in colorectal cancers is inconclusive as of yet. The purpose of this study is shed light on PTEN expression in colorectal cancer and its significance associated with pathological findings and clinical findings. METHODS: A total of 217 patients who had been diagnosed with colorectal cancer, had undergone radical colectomy from October of 1993 to December of 2000, and for whom follow-up was possible were selected for this study. Their clinical records were analyzed and specimens were stained immunohistochemically RESULTS: In comparing the PTEN positive group (48 patients, 22.1%) with the negative group (171 patients, 77.9%), there was a significantly (P=0.021) higher frequency of recurrence in the negative group (29.0%) than in the positive group (12.5%), and an especially higher frequency of distant metastasis in the negative group (18.3%) than in the positive group (4.2%), with P=0.010. Although there was no meaningful difference in the overall five year survival rate, the five year disease free survival rate was significantly (P=0.029) higher in the positive group. CONCLUSIONS: The results of this study reveal the possibility of using PTEN as a prognostic indicator in colorectal cancer.