Immunohistochemical analysis of K-RAS expression in curatively treated colorectal cancer patients: Correlations of clinicopathological features with clinical outcome
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- Avgoustou, C., Giannousis, D., Penlidis, P. et al. Hellenic J Surg (2013) 85: 165. doi:10.1007/s13126-013-0031-7
The study was conducted to assess the relationship between the presence of K-RAS oncogene expression in samples of colorectal carcinomas (CRC) and the clinicopathological data of investigated patients.
One hundred patients (55 females/mean age 64.55 years) with curable CRC treated during period 1/1/2000–31/12/2006 were studied. Eligibility criteria for cases included diagnosis with first primary incident CRC, age up to 75 years, and mental competence. Patients with distant metastasis, severe concomitant disease, coexistent malignancy, ulcerative colitis or Crohn’s disease, familial adenomatous polyposis, or immediate severe complication or death were excluded. The tumours concerned adenocarcinomas at TNM stages 0-I (26 patients), II (46 patients), and III (28 patients). Eighty-seven patients received chemotherapy, chemoradiotherapy or radiotherapy. All tumour specimens were reviewed for immunohistochemistry. Expressions of K-RAS and secondarily P53 were identified, and intensity/distribution was evaluated. All clinicopathological parameters were recorded. The cross-tabulation technique was used for variance analysis. P-values ≤0.05 were considered statistically significant.
At 5-year-follow-up, 11 deaths had occurred (stages II:4, III:7) among 20 recurrences (N1:8, N2:2). Deaths were associated with moderate (3 patients), moderate-intense (2 patients) and intense (6 patients) K-RAS staining (p=0.008), and with invasiveness of the tumour (p=0.0089), lymphnode metastasis (p<0.0001) and worse tumour differentiation (p<0.0001). A statistical significance was revealed among the general population between K-RAS intense staining and both worse tumour differentiation (p=0.0066) and N1 lymph-node metastasis (p=0.0469). A statistical significance between K-RAS and P53 expressions in women with T3 tumours was also noted (p=0.0387).
K-RAS overexpression correlated well with worse differentiation, lymph-node metastasis and invasive histologic mode in CRC.