Suppressor in HCC. However, the mechanistic nature of SIRT3 in inhibiting HCC progression remains poorly unknown, and it therefore deserts a challenge for future investigation.SIRT3 as a Prognostic Biomarker in HCCTable 3. Cox multivariate analyses of prognostic factors on overall survival.Variable Tumor multiplicity Tumor size AFP Differentiation Vascular invasion 
Stage Relapse SIRTb 0.141 0.116 0.750 20.020 0.519 0.954 0.807 20.SE 0.266 0.213 0.229 0.197 0.219 0.344 0.219 0.Hazard ratio (95 CI) 1.152 (0.683?.942) 1.124 (0.740?.706) 2.117 (1.352?.316) 0.981 (0.667?.442) 1.680 (1.093?.582) 2.596 (1.322?.100) 2.241 (1.459?.443) 0.555 (0.344?.897)P value0.596 0.585 0.001 0.921 0.018 0.006 0.000 0.worse prognosis. Strikingly, low SIRT3 expression could also predict poor overall survival of HCC patients with tumor size (,5 cm), grade (I-II), or stage (I-II). This suggested that decrease of SIRT3 in HCC could be of clinical significance for predicting outcome 22948146 of surgical 307538-42-7 cost treatment in a subset of HCC patients. In summary, our study provided vigorous evidence that low SIRT3 15481974 expression was frequently present in HCC, particularly in those poor-differentiated cases. Decrease of SIRT3 in HCC was significantly correlated with clinical 
stage, serum AFP level, tumor differentiation and tumor multiplicity, indicating that SIRT3 might be 520-26-3 site involved in HCC progression. Importantly, although little information of SIRT3 in hepatocarcinogenesis is available, our study suggests that low expression of SIRT3, as detected by IHC, may be useful for predicting the postoperative survival of HCC patients.b, Regression coefficient; SE, standard error; CI, confidence interval; AFP, alphafetoprotein. doi:10.1371/journal.pone.0051703.tSupporting InformationFigure S1 Percentages of high SIRT3 expressions in noncancerous tissue adjacent to HCC tissue were indicated by histogram. (TIF) Figure S2 Relation of SIRT3 expression with recurrence-free survival in pathological HCC subgroups. Survival analysis was performed in subgroups according to the factors that are attributed to worse outcome of HCC patients, using Kaplan-Meier survival analysis (log-rank test). (TIF) Figure S3 Survival analysis of SIRT3 expression in HCCLow SIRT3 expression has been identified as a poor independent prognostic factor for both overall survival and recurrence-free survival in postsurgical HCC patients in this study. There is no previous study reporting the association between SIRT3 expression and prognosis in cancer. However, high SIRT1 expression was reported to connect to poor survival in diffuse large B-cell lymphoma [40], gastric carcinoma [41], and breast cancer [42]. Furthermore, downregulation of SIRT1 in HCC resulted in abrogation of cell proliferation and enhanced sensitivity to doxorubicin treatment by induction of senescence or apoptosis [43,44]. The finding that patients with high SIRT3 expression survived longer could be supported by that SIRT3 was capable of inducing apoptosis. In colorectal carcinoma, SIRT3 was response to stress-induced apoptosis [37]. In leukemia cells, increasing SIRT3 contributed to apoptosis caused by Kaempferol treatment [45]. In HCC cells, overexpression of SIRT3 led to activation of JNK and the resulting apoptosis [19]. Importantly, low SIRT3 expression associated to markedly shorter period of clinical recurrence. This observation suggests that more attention should be paid to HCC patients with low SIRT3 expression during and after the process of therapy,.Suppressor in HCC. However, the mechanistic nature of SIRT3 in inhibiting HCC progression remains poorly unknown, and it therefore deserts a challenge for future investigation.SIRT3 as a Prognostic Biomarker in HCCTable 3. Cox multivariate analyses of prognostic factors on overall survival.Variable Tumor multiplicity Tumor size AFP Differentiation Vascular invasion Stage Relapse SIRTb 0.141 0.116 0.750 20.020 0.519 0.954 0.807 20.SE 0.266 0.213 0.229 0.197 0.219 0.344 0.219 0.Hazard ratio (95 CI) 1.152 (0.683?.942) 1.124 (0.740?.706) 2.117 (1.352?.316) 0.981 (0.667?.442) 1.680 (1.093?.582) 2.596 (1.322?.100) 2.241 (1.459?.443) 0.555 (0.344?.897)P value0.596 0.585 0.001 0.921 0.018 0.006 0.000 0.worse prognosis. Strikingly, low SIRT3 expression could also predict poor overall survival of HCC patients with tumor size (,5 cm), grade (I-II), or stage (I-II). This suggested that decrease of SIRT3 in HCC could be of clinical significance for predicting outcome 22948146 of surgical treatment in a subset of HCC patients. In summary, our study provided vigorous evidence that low SIRT3 15481974 expression was frequently present in HCC, particularly in those poor-differentiated cases. Decrease of SIRT3 in HCC was significantly correlated with clinical stage, serum AFP level, tumor differentiation and tumor multiplicity, indicating that SIRT3 might be involved in HCC progression. Importantly, although little information of SIRT3 in hepatocarcinogenesis is available, our study suggests that low expression of SIRT3, as detected by IHC, may be useful for predicting the postoperative survival of HCC patients.b, Regression coefficient; SE, standard error; CI, confidence interval; AFP, alphafetoprotein. doi:10.1371/journal.pone.0051703.tSupporting InformationFigure S1 Percentages of high SIRT3 expressions in noncancerous tissue adjacent to HCC tissue were indicated by histogram. (TIF) Figure S2 Relation of SIRT3 expression with recurrence-free survival in pathological HCC subgroups. Survival analysis was performed in subgroups according to the factors that are attributed to worse outcome of HCC patients, using Kaplan-Meier survival analysis (log-rank test). (TIF) Figure S3 Survival analysis of SIRT3 expression in HCCLow SIRT3 expression has been identified as a poor independent prognostic factor for both overall survival and recurrence-free survival in postsurgical HCC patients in this study. There is no previous study reporting the association between SIRT3 expression and prognosis in cancer. However, high SIRT1 expression was reported to connect to poor survival in diffuse large B-cell lymphoma [40], gastric carcinoma [41], and breast cancer [42]. Furthermore, downregulation of SIRT1 in HCC resulted in abrogation of cell proliferation and enhanced sensitivity to doxorubicin treatment by induction of senescence or apoptosis [43,44]. The finding that patients with high SIRT3 expression survived longer could be supported by that SIRT3 was capable of inducing apoptosis. In colorectal carcinoma, SIRT3 was response to stress-induced apoptosis [37]. In leukemia cells, increasing SIRT3 contributed to apoptosis caused by Kaempferol treatment [45]. In HCC cells, overexpression of SIRT3 led to activation of JNK and the resulting apoptosis [19]. Importantly, low SIRT3 expression associated to markedly shorter period of clinical recurrence. This observation suggests that more attention should be paid to HCC patients with low SIRT3 expression during and after the process of therapy,.