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Nrgastro.2012.208

24. Feb 2014
Nrgastro.2012.208
Nrgastro.2012.208
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Nrgastro.2012.208

  1. NEWS & VIEWS DIAGNOSIS Novel prognostic biomarkers in hepatocellular carcinoma Roberta W. C. Pang and Ronnie T. P Poon . Hepatocellular carcinoma (HCC) is a heterogeneous cancer with variable outcomes after treatment. Prognosis of HCC cannot be accurately predicted by current clinical staging systems. Development of prognostic biomarkers is critical to improve treatment outcome. Recent studies indicate that inflammatory and immunological markers might provide reliable prognostic classification in HCC. Hepatocellular carcinoma (HCC) is a common cancer worldwide, related to the high prevalence of HBV and HCV infec­ tion. Despite advances in surgical and non­ surgical treatments, the prognosis for patients with HCC remains unsatisfactory compared with many other common human cancers. A major obstacle hindering improvement in treatment outcome is the difficulty in predict­ ing treatment response, owing to the hetero­ geneity of not only the cancer itself but also the underlying chronic liver disease. Although current clinical staging systems provide a rough framework of prognostic classification and treatment decision for HCC, identifica­ tion of prognostic biomarkers could further enhance outcome prediction and treatment selection. Thus far, most research has focused on mol­ cular biomarkers based on tumour e molecular biology. Two recent papers have highlighted the relevance of inflammatory and immunological responses of the host in predicting prognosis of HCC. Sieghart et al.1 reported that high levels of C‑reactive protein (CRP) at the time of diagnosis pre­ dicts poor long-term survival of patients with HCC, whereas Fu et al.2 showed that impairment of CD4+ cytotoxic T lympho­cytes (CTLs) predicts poor outcome. The study of inflammatory markers is of particular relevance in HCC as the develop­ ment of this cancer is usually associated with chronic inflammation. CRP is an acute-phase protein produced by the liver in inflammatory conditions and it has a role in linking innate immunity and inflammation. The importance of serum levels of CRP to prognosis has been evaluated previously in HCC.3,4 Raised levels of CRP have been shown to predict early recurrence and poor survival in patients Photodisc/Getty Pang, R. W. C. & Poon, R. T. P Nat. Rev. Gastroenterol. Hepatol. 9, 691–692 (2012); published online 13 November 2012; doi:10.1038/nrgastro.2012.208 . undergoing surgical resection for HCC.3 Furthermore, raised levels of CRP have also been demonstrated to predict recurrence and poor survival after liver transplantation for HCC.4 In the new study, Sieghart et al.1 studied the prognostic importance of serum levels of CRP in patients with HCC under­ going nonsurgical treatment. They used a training cohort of 466 patients in one institu­ tion to identify the optimum cut-off CRP level (1 mg/dl, equivalent to 95.2 nmol/l), and then evaluated the influence on prognosis of high versus low CRP levels according to this cut-off value in a validation cohort of 252 patients treated at another institution.1 The study showed that raised levels of CRP was a pre­ dictor of poor survival in multivariate analy­ sis independent of other clinical factors. More importantly, CRP level was demonstrated to have independent prognostic value after strat­ ification by the Barcelona Clinic Liver Cancer classification, suggesting that CRP level can be added to the clinical staging system to further subcategorize patients in terms of prognosis. However, certain issues need to be further addressed. First, the training cohort in the NATURE REVIEWS | GASTROENTEROLOGY & HEPATOLOGY © 2012 Macmillan Publishers Limited. All rights reserved Sieghart et al.1 study included a wide spec­ trum of patients: those with early-stage cancer treated with ablation; intermediatestage cancer treated with transarterial chemo­ embolization (TACE); and advanced-stage cancer treated with systemic therapy. By contrast, the validation cohort included only patients treated with TACE. Whether the prognostic value of CRP could be extended to patients with early cancer undergoing ablation or those with advanced cancer undergoing systemic therapy, and whether the same cut-off value could be applied, is unclear from this study. Second, although the study showed that raised levels of CRP were more common in patients with HCC compared with patients with cirrhosis only, the relative contribution by the cancer and the underlying liver disease to the CRP level in the patients is unclear. This aspect might be better evaluated by correlating CRP level with transaminase levels, which reflect levels of inflammation in the liver. Third, assum­ ing that the increased CRP levels were related to the tumour (as proposed by the authors), the biological relevance of CRP in tumour progression has not been elucidated. In the discussion, the authors suggested that the inflammatory response associated with high CRP levels could be directly involved in tumour progression of HCC. They further proposed IL‑6—one of the main inducers of CRP production—as a possible mediator of tumour progression as IL‑6 has been previ­ ously shown to promote tumour growth and metastasis. However, the study by Sieghart and colleagues1 did not evaluate IL‑6 levels in the participants. Another study of 110 patients undergoing locoregional therapy for HCC did, however, evaluate serum VOLUME 9  |  DECEMBER 2012  |  691
  2. NEWS & VIEWS levels of both CRP and IL‑6.5 This study showed that the levels of both markers were raised in patients with HCC compared with healthy individuals, and high levels of both biomarkers were associated with poor sur­ vival. However, in multivariate analysis, only IL‑6 was an independent prognostic factor. Further studies are needed to clarify the rela­ tive influence of serum levels of CRP and IL‑6 in prognosis for patients with HCC. The study of immunological response to tumours is important to understand the mechanism of tumour immune evasion, and also to provide insight into potential immuno­ herapy strategies. Fu et al.2 studied t circulating and tumour-­ nfiltrating CD4+ i CTLs in patients with HCC and observed that a decrease in the number of CD4+ CTLs was closely associated with progressive stages of HCC and poor survival.2 The authors inves­ tigated the potential regulatory mechanism involved in the decrease in CD4+ CTLs and showed that the number of CD4+ CTLs was negatively correlated with the number of T-regulatory (TREG) cells. Furthermore, they performed in vitro experiments to demon­ strate that TREG cells inhibited release of cytolytic molecules (such as granzyme and perforin) by CD4+ CTLs and the genera­ tion of CD4+ CTLs. In this study, prognostic importance of circulating and tumour CD4+ CTLs was studied in two different cohorts of patients over different time periods: cir­ culating CD4+ CTLs were evaluated in 232 patients with HCC between 2005 and 2012; and tumour CD4+ CTLs were evaluated using immuno­ istochemical staining in h 315 patients undergoing resection for HCC between 2001 and 2004. Although both circu­ lating and tumour CD4+ CTLs were shown to be independent prognostic factors in multi­ variate analysis in the respective cohorts, it remained unclear whether circulating and tumour-infiltrating CD4+ CTLs were cor­ related with each other, and which cell type might provide the best prognostic informa­ tion. The use of circulating CD4+ CTLs is perhaps more practical for prognostic clas­ sification as tumour samples might not be available in patients with advanced HCC undergoing non­ urgical therapies. s Immunosuppression by TREG cells was shown to be an important immune mecha­ nism of tumour evasion in patients with HCC by previous studies.6,7 An existing study sug­ gested that TREG cells could enhance tumour progression through suppression of the effec­ tor function of CD8+ T cells.7 The current study by the same group of authors provided an additional mechanism through which TREG 692  |  DECEMBER 2012  |  VOLUME 9 cells might enhance tumour escape from host immune system.2 Another study has corrobo­ rated the importance of TREG cells in restrain­ ing antitumour immunity in primary and secondary liver cancer.8 The elucidation of the mechanisms that underlie immune evasion is crucial in designing immunotherapy for HCC. Interestingly, a study published in 2010 suggested that low-dose cyclophospha­ mide might suppress TREG cells and unmask α‑fetoprotein (AFP)-specific CD4+ T‑cell response in patients with advanced HCC.9 AFP is a specific tumour-associated antigen of HCC, and induction of anti-AFP CD4+ T‑cell response represents cell-mediated immune responses to the tumour cells. TREG cells and CD4+ T cells seem to be potential targets in immunotherapy for HCC. To improve the management of HCC, it is imperative to identify prognostic biomarkers to aid clinical staging. Molecular biomarkers based on tumour biology of HCC (such as gene-expression profile and expression of angiogenic factors) have been widely studied and found to have prognostic implications.10 Inflammatory and immuno­ogical prognos­ l tic biomarkers reflect the host response to the tumour and therefore can supplement tumour biology markers to provide a more comprehensive picture of prognostic predic­ tion. However, future studies based on large prospective cohorts are required to validate their prognostic value before they can be translated into clinical use. Department of Surgery & Centre for Cancer Research, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong, China (R. W. C. Pang, R. T. P Poon). . Correspondence to: R. T. P. Poon poontp@hku.hk Acknowledgements The authors would like to acknowledge grant support from the Strategic Research Theme Grant of the Centre for Cancer Research of the Faculty of Medicine, The University of Hong Kong. Competing interests The authors declare no competing interests. 1. Sieghart, W. et al. A single determination of C‑reactive protein at the time of diagnosis predicts long-term outcome of hepatocellular carcinoma. Hepatology http://dx.doi.org/ 10.1002/hep.26057. 2. Fu, J. et al. The impairment of CD4+ cytotoxic T cells predicts poor survival and high recurrence rates in patients with hepatocellular carcinoma. Hepatology http://dx.doi.org/10.1002/ hep.26054. 3. Hashimoto, K. et al. The impact of preoperative serum C‑reactive protein on the prognosis of patients with hepatocellular carcinoma. Cancer 103, 1856–1864 (2005). 4. An, H. J. et al. Serum C‑reactive protein is a useful biomarker to predict outcomes after liver transplantation in patients with hepatocellular carcinoma. Liver Transpl. http://dx.doi.org/ 10.1002/lt.23512. 5. Jang, J. W. et al. Serum interleukin‑6 and C‑reactive protein as a prognostic indicator in hepatocellular carcinoma. Cytokine http:// dx.doi.org/10.1016/j.cyto.2012.07.117. 6. Fu, J. et al. Increased regulatory T cells correlate with CD8 T‑cell impairment and poor survival in hepatocellular carcinoma patients. Gastroenterology 132, 2328–2339 (2007). 7. Zhou, J. et al. Increased intratumoral regulatory T cells are related to intratumoral macrophages and poor prognosis in hepatocellular carcinoma patients. Int. J. Cancer 125, 1640–1648 (2009). 8. Pedroza-Gonzalez, A. et al. Activated tumorinfiltrating CD4+ regulatory T cells restrain antitumor immunity in patients with primary or metastatic liver cancer. Hepatology http:// dx.doi.org/10.1002/hep.26013. 9. Greten, T. F. et al. Low-dose cyclophosphamide treatment impairs regulatory T cells and unmasks AFP-specific CD4+ T‑cell responses in patients with advanced HCC. J. Immunother. 33, 211–218 (2010). 10. Pang, R. W. et al. Biology of hepatocellular carcinoma. Ann. Surg. Oncol. 15, 962–971 (2008). ULCERATIVE COLITIS UCCIS—a reproducible tool to assess mucosal healing Helmut Neumann and Markus F. Neurath In an attempt to better characterize mucosal healing in ulcerative colitis, various endoscopic scoring systems have been introduced. However, most have limited interobserver agreement. A recent study has validated the ulcerative colitis colonoscopic index of severity and found that this new scoring system provides reproducible results among gastroenterologists. Neumann, H. & Neurath, M. F. Nat. Rev. Gastroenterol. Hepatol. 9, 692–694 (2012); published online 16 October 2012; doi:10.1038/nrgastro.2012.198 The ulcerative colitis colonoscopic index of severity (UCCIS) is a newly introduced scoring system that was developed in a preliminary study that assessed 10 types of mucosal lesions (that is, oedema, erythema, stricture, loss of haustral folds, rigidity, www.nature.com/nrgastro © 2012 Macmillan Publishers Limited. All rights reserved
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