OBJECTIVETo investigate the expression level of high mobility group box-1 (HMGB1) in human colorectal cancer and its relation with different clinicopathological characteristics and prognosis of colorectal cancer patients.

METHODSImmunohistochemical method was used to detect the HMGB1 expression in tissue samples of 86 colorectal cancer patients and 32 normal colorectal tissue samples. Positive rates of HMGB1 expression were compared among different clinicopathological characteristics. Relation of HMGB1 expression with survival was analyzed.

RESULTSHMGB1 expression was mainly in colorectal cancer cell nucleus, with a few appearance of co-expression in nucleus and cytoplasm. Positive rate of HMGB1 expression in normal tissues was significantly lower than that in colorectal cancers [9.4% (3/32) vs. 66.3% (57/86), P=0.000], and it was much higher in large cancers, lower differentiation, invasion to outside serosa, advanced clinical stage and lymph node metastasis (all P<0.05), but was similar in terms of age and gender (P>0.05). Survival analysis showed that 3-year survival rate of patients with positive HMGB1 expression was significantly lower as compared to those with negative HMGB1 expression (56.1% vs. 85.7%, P=0.021), meanwhile it was significantly lower in patients with co-expression in nucleus and cytoplasm as compared to those with simple nuclear expression (41.4% vs. 75.0%, P=0.013).

CONCLUSIONSHMGB1 expression in colorectal cancer is high, and its positive rate increases with the low differentiation, invasion and metastasis. HMGB1 co-expression in nucleus and cytoplasm indicates poor prognosis of colorectal cancer patients.