The expression of high-mobility group protein box 1 correlates with the progression of non-small cell lung cancer

High-mobility group protein box 1 (HMGB1) released from dying tumor cells promotes tumor progression, on the other hand HMGB1 activates dendritic cells and triggers anti-neoplastic response of T-cells in chemotherapy and radiotherapy. HMGB1 expression is up-regulated in many kinds of tumors. To investigate HMGB1 expression in non-small cell lung cancer, 63 patients were enrolled and tumor tissues were collected with matched normal lung tissues. HMGB1 mRNA and protein levels were quantified with real-time PCR, Western blots and immunohistochemistry. The HMGB1 expression in tumor tissue was lower than in matched normal lung tissue at mRNA levels (Paired t-test, t<0.001) and the down-regulation in stage III-IV patients was also significantly greater than one in stage I-II (one-way ANOVA, p=0.005). At protein level, HMGB1 expression was also down-regulated. Low HMGB1 expression in non-small cell lung cancer may explain the poor therapeutical outcome during chemotherapy and radiotherapy.