Overexpression of high-mobility group box 2 is associated with tumor aggressiveness and prognosis of hepatocellular carcinoma.
OBJECTIVE
We investigated the expression of high-mobility group box 2 (HMGB2) in patients with hepatocellular carcinoma (HCC) and its clinical effects with underlying mechanisms.


METHODS
HMGB2 mRNA levels were measured in 334 HCC patients by real-time reverse transcription-PCR and HMGB2 protein levels in 173 HCC patients by immunohistochemical studies. The HMGB2 expression level was measured by Western blotting for three HCC cell lines. To clarify the precise role of HMGB2 on cell proliferation, we did in vitro analysis with expression vectors and small interfering RNAs.


RESULTS
HMGB2 mRNA and protein expression were significantly higher in HCC than in noncancerous surrounding tissues (P < 0.0001) and showed a positive correlation (ρ = 0.35, P < 0.001). HMGB2 overexpression was significantly correlated with shorter overall survival time, both at mRNA (P = 0.0054) and protein level (P = 0.023). Moreover, HMGB2 mRNA level was an independent prognostic factor for overall survival in a multivariate analysis (P = 0.0037). HMGB2 knockdown by small interfering RNAs decreased cell proliferation, and overexpression of HMGB2 by expression vectors diminished cisplatin- and etoposide-induced cell death.


CONCLUSIONS
Our clinical and in vitro data suggest that HMGB2 plays a significant role in tumor development and prognosis of HCC. These results can partly be explained by altered cell proliferations by HMGB2 associated with the antiapoptotic pathway.
Kwon
Jung-Hee
JH
Department of Life Science, Pohang University of Science and Technology, Hyoja-Dong, Pohang, South Korea.
Kim
Jongmin
J
Park
Jin Young
JY
Hong
Sun Mi
SM
Park
Chang Wook
CW
Hong
Seok Joo
SJ
Park
Sun Young
SY
Choi
Yoon Jung
YJ
Do
In-Gu
IG
Joh
Jae-Won
JW
Kim
Dae Shick
DS
Choi
Kwan Yong
KY
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000378:metabolism*; D016923:Cell Death; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D024261:HMGB2 Protein / Q000096:biosynthesis* / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
D024261:HMGB2 Protein; D012333:RNA, Messenger