Thymidylate synthase expression, p53, bcl-2, Ki-67 and p27 in colorectal cancer: relationships with tumor recurrence and survival.

It was the objective to determine in this retrospective study whether thymidylate synthase (TS), p53, bcl-2, Ki-67 and p27 in Dukes' stage B and stage C (AJCC/UICC stage II and III) colorectal adenocarcinoma were predictive of disease-free survival (DFS) and overall survival (OS). Paraffin-embedded specimens from 103 patients with colorectal cancer, treated with surgery between October 1994 and September 1999, were examined for TS expression, p53, bcl-2, Ki-67 and p27 using immunohistochemistry; 51 cases were Dukes' stage B and 52 cases were Dukes' stage C disease. Adjuvant 5-FU-based chemotherapy was given to all patients, while 31 having rectal malignancy also received pelvic radiotherapy. Data were associated with the recurrence rate and survival. With a median follow-up of 5 years, 38 patients (36.8%) developed recurrence and as many patients (36.8%) died. TS was overexpressed in 16 cases (15.6%), p53 nuclear oncoprotein accumulation in >10% of cells occurred more frequently [61 of 103 cases (59.3%)], positive expression of bcl-2 protein in >10% of cells was observed in 41 of 103 cases (39.9%), 57 patients (55.4%) showed immunohistochemical expression of Ki-67 and there were 75 cases (72.9%) with p27 accumulation. The pathological stage was the only independent prognostic factor for DFS (p = 0.042). Sex, as well as age and biological prognostic factors, had no significant impact value on DFS and OS. A multivariate analysis of OS demonstrated that stage C, p53 negative and Ki-67 positive were associated significantly with an unfavorable outcome and a worse median OS (p = 0.035 and t ratio = 2.48). Some biological characteristics such as p53 and Ki-67 status may provide useful prognostic information in addition to the classical clinicopathological parameters. However, further studies are needed to clarify the value of adopting biological prognostic factors into clinical practice. Copyright 2004 S. Karger AG, Basel.