Prognostic significance of pathological biomarkers in patients with stage II-III colorectal cancer
14518 Background: Biopathological colorectal cancer (CRC) studies have provided information on pathogenesis, but it is unclear how important biomarkers actually are in predicting prognosis. The aim of our study was to define the prognostic significance of biomarkers and a biopathological profile that could predict an increase in the disease relapse risk in stage II-III CRC patients (pts). Methods: The primary tumor of the CRC pts treated with surgery was immunohistochemically evaluated on the Ki67, p53, bcl-2, TS, EGFR, MLH1 and MSH2 expressions. All 7 markers were measured using standard immunohistochemical techniques. The biomarker evaluations were scored by just one pathologist. Results: Between March 2001 and October 2006 the primary tumor of 242 consecutive pts was investigated. Pt characteristics were: males 141(58.3%), females 101(41.7%); median age 68.5 (24–88); primary tumor site: right colon 94(38.8%), left colon 148(61.2%); stage II 102(42.1%), stage III 81(33.5%), stage IV 59(24.4%). 5-fluorouracil based adjuvant chemotherapy was performed in 121 (66.1%) pts. After a median follow up of 30 months (1–80), 34 pts (10 pts stage II, 24 pts stage III) of 183 stage II-III pts (18.6%) had a disease recurrence. In a univariate analysis of stage II-III pts, a higher expression of Ki67 (= 50% positive cells) was significantly associated with an improved DFS (p= 0.014) and overall survival (OS) (p=0.010). Expression of p53, bcl-2, TS, EGFR, MLH1 and MSH2 were not significantly associated with DFS and OS. In a multivariate analysis adjusted for the impact of the disease stage and adjuvant chemotherapy, a higher expression of Ki67 was significantly associated with diminished risk of recurrence (HR: 0.395; 95% CI: 0.183–0.855, p=0.018) and death (HR: 0.179; 95% CI: 0.046–0.696, p=0.013). The evaluation of DNA mismatch repair status (MLH1, MSH2) demonstrated that the lack of MLH1 is more frequent in non-relapsed II-III stage pts than in IV stage pts (p= 0.024). Conclusions: This analysis showed a significant correlation between higher Ki67 expression and better DFS and OS in pts with stage II-III CRC. An higher frequency of MLH1 deficiency was observed in non-relapsed pts with stage II-III than in advanced disease. No significant financial relationships to disclose.