Prognostic value of B-cell linker protein in colorectal cancer

This study aimed to investigate the clinicopathological and prognostic impact of B-cell linker (BLNK) protein expression in colorectal cancer (CRC) as its function in CRC remains unexplored. We performed immunohistochemical staining for BLNK using tissue microarrays of 418 consecutive CRC samples; of these 10 were excluded due to inappropriate staining. The expression intensity and staining level was scored as 0-3 and 0-4, respectively, based on the percentage of positive cells. The immunoreactivity score (IRS) was calculated by multiplying these two scores. BLNK expression was observed in 222 patients (54.4 %). Lymph node metastasis (p = 0.031), right colon cancer (p = 0.026), mutinous adenocarcinoma (p < 0.001), and perineural invasion (p = 0.049) were more frequently observed in the IRS 4-12 group than in the IRS 0-3 group. At the same cutoff point, the 5-year recurrence-free survival rate of the patients with stage HI was significantly lower than that observed in IRS 4-12 group (74.8 % +/- 4.2 % vs. 54.2 +/- 8.5 %, p = 0.003). Multivariate analysis revealed IRS 4-12 to be an independent risk factor for recurrence (Hazard ratio 2.346, 95 % confidence interval 1.348-4.085, p = 0.003). In conclusion, overexpression of BLNK protein is an independent risk factor for CRC recurrence.