Natural immunity has significant impact on immune responses against cancer

Clinical applications of squamous cell carcinoma antigen-immunoglobulins M to monitor chronic hepatitis C

Hepatitis C virus (HCV) is the main cause of chronic liver disease and cirrhosis in Western countries. Over time, the majority of cirrhotic patients develop hepatocellular carcinoma (HCC), one of the most common fatal cancers worldwide - fourth for incidence rate. A high public health priority need is the development of biomarkers to screen for liver disease progression and for early diagnosis of HCC development, particularly in the high risk population represented by HCV-positive patients with cirrhosis. Several studies have shown that serological determination of a novel biomarker, squamous cell carcinoma antigen-immunoglobulins M (SCCA-IgM), might be useful to identify patients with progressive liver disease. In the initial part of this review we summarize the main clinical studies that have investigated this new circulating biomarker on HCV-infected patients, providing evidence that in chronic hepatitis C SCCA-IgM may be used to monitor progression of liver disease, and also to assess the virological response to antiviral treatment. In the last part of this review we address other, not less important, clinical applications of this biomarker in hepatology.

Diagnostic and prognostic role of SCCA-IgM serum levels in hepatocellular carcinoma (HCC)

BACKGROUND AND AIM

The serpin squamous cell carcinoma antigen complexed with IgM (SCCA-IgM) has been reported as a promising serological marker for hepatocellular carcinoma (HCC). We aimed to further evaluate SCCA-IgM diagnostic accuracy and to determine its prognostic role.

METHODS

SCCA-IgM levels were determined in 327 sera obtained from 81 HCC patients, 206 cirrhotics and 40 healthy blood donors (controls). Sensitivity, specificity, correlation with clinical and tumor parameters and with survival were evaluated.

RESULTS

HCC patients had SCCA-IgM levels significantly higher than controls and cirrhotics (P < 0.0001). Sensitivity, specificity, positive and negative predictive values for HCC were 89%, 50%, 41% and 92%, respectively. In comparison, sensitivity and specificity for alphafetoprotein were 48% and 85%. SCCA-IgM levels were not significantly correlated with clinical or biological variables. With a cut-off of 130 AU/mL (receiver operating characteristic curves), SCCA-IgM proved efficient in the prediction of prognosis, identifying the patients with long overall survival (efficiency validated in the homogenous subgroup of patients with intermediate-stage HCC undergoing transarterial chemoembolization) and predicting progression-free survival. A Cox multivariate analysis confirmed SCCA-IgM predictive value, identifying tumor size and SCCA-IgM levels as independent predictors of survival. A reduction in SCCA-IgM levels correlated with response to treatment.

CONCLUSIONS

SCCA-IgM is a sensitive marker of HCC in patients with cirrhosis even though lacking in specificity. The determination of the levels of the marker in HCC patients is highly efficient in predicting the patients' prognosis, identifying those with long overall and progression-free survival and the responders and should be introduced in the clinical practice.

Correlation between infiltration of FOXP3+ regulatory T cells and expression of B7-H1 in the tumor tissues of gastric cancer

BACKGROUND

Substantial evidence suggests that the expansion of regulatory T cells (T(regs)) plays a pivotal role in immunological evasion of tumors. Recent studies have demonstrated that a majority of tumor cells overexpress B7-H1, and this overexpression is associated with poor disease prognosis. Although an increase of T(regs) and B7-H1 has been revealed in several malignancies, their correlation in gastric cancer has not been studied.

METHODS

Tumor sections from 111 gastric cancer patients were stained for FOXP3 and B7-H1 by immunohistochemistry. The expression levels of these two molecules were statistically associated with various factors involved in disease progression and prognosis. The correlation between their expression levels was analyzed.

RESULTS

The infiltration of FOXP3(+) T(regs) and expression of B7-H1 were observed in gastric cancer tissues, and there was a highly significant correlation between these two molecules (P < 0.01). The expression of FOXP3(+) T(regs) and B7-H1 was associated with lymph node metastasis and the clinicopathological stage and prognosis of gastric cancer patients. The expression levels of these two determinants in patients with lymph node metastasis and an advanced clinicopathological stage were distinctly higher (P < 0.05). The patients with enhanced expression of FOXP3(+) T(regs) and B7-H1 exhibited a lower overall survival rate and a worse prognosis (P < 0.05).

CONCLUSIONS

Increased expression of FOXP3(+) T(regs) and B7-H1 was observed in gastric cancer tissues; the two molecules were closely correlated with each other, suggesting that they might be used as new biomarkers to predict the disease progression and prognosis. Combinatorial immunotherapeutic approaches based on depleting the T(regs) and blocking B7-H1 might improve therapeutic efficacy in gastric cancer.

Lentinan enhances the efficacy of the DCF regimen in patients with advanced gastric cancer: an analysis of 40 cases

AIM: To evaluate whether lentinan enhances the curative effects of the DCF (docetaxel, cisplatin and fluorouracil) regimen in patients with advanced gastric cancer.

METHODS: Eighty patients with stages III and IV gastric cancer who were treated at our hospital between January 2007 and December 2008 were randomly divided into two groups to receive DCF chemotherapy alone or DCF chemotherapy in combination with lentinan. The curative effects, routine blood parameters, lymphocyte subsets and quality of life were compared between the two groups.

RESULTS: The disease control rate was significantly higher in the lentinan plus DCF group than in the DCF group (87.5% vs 75.0%, P < 0.05), while the incidence of side effects (including neutropenia, leukopenia, anemia, thrombocytopenia and infection) was significantly lower in the lentinan plus DCF group than in the DCF group (P < 0.05). No significant differences were noted in routine blood parameters, lymphocyte subsets and quality of life before chemotherapy between the two groups (all P > 0.05). After chemotherapy, the numbers of WBC, lymphocytes, CD3⁺, CD4⁺, CD8⁺, NK cells and quality of life were significantly improved in the lentinan plus DCF group compared to the DCF group (all P < 0.05).

CONCLUSION: Lentinan significantly enhanced the efficacy and safety of the DCF regimen in patients with advanced gastric cancer.

Photodynamic therapy: illuminating the road from cell death towards anti-tumour immunity

Photodynamic therapy (PDT) utilizes the destructive power of reactive oxygen species generated via visible light irradiation of a photosensitive dye accumulated in the cancerous tissue/cells, to bring about their obliteration. PDT activates multiple signalling pathways in cancer cells, which could give rise to all three cell death modalities (at least in vitro). Simultaneously, PDT is capable of eliciting various effects in the tumour microenvironment thereby affecting the tumour-associated/-infiltrating immune cells and by extension, leading to infiltration of various immune cells (e.g. neutrophils) into the treated site. PDT is also associated to the activation of different immune phenomena, e.g. acute-phase response, complement cascade and production of cytokines/chemokines. It has also come to light that, PDT is capable of activating 'anti-tumour adaptive immunity' in both pre-clinical as well as clinical settings. Although the ability of PDT to induce 'anti-cancer vaccine effect' is still debatable, yet it has been shown to be capable of inducing exposure/release of certain damage-associated molecular patterns (DAMPs) like HSP70. Therefore, it seems that PDT is unique among other approved therapeutic procedures in generating a microenvironment suitable for development of systemic anti-tumour immunity. Apart from this, recent times have seen the emergence of certain promising modalities based on PDT like-photoimmunotherapy and PDT-based cancer vaccines. This review mainly discusses the effects exerted by PDT on cancer cells, immune cells as well as tumour microenvironment in terms of anti-tumour immunity. The ability of PDT to expose/release DAMPs and the future perspectives of this paradigm have also been discussed.

Experimental validation of specificity of the squamous cell carcinoma antigen-immunoglobulin M (SCCA-IgM) assay in patients with cirrhosis

BACKGROUND

Squamous cell carcinoma antigen-immunoglobulin M (SCCA-IgM) is a useful biomarker for the risk of development of hepatocellular carcinoma (HCC) in patients with cirrhosis due to its progressive increase associated to HCC evolution. In patients with cirrhosis, other assays have been affected by interfering reactivities of IgM. In this study, the analytical specificity of the SCCA-IgM assay was assessed by evaluating SCCA-IgM measurement dependence on different capture phases, and by measuring the recovery of SCCA-IgM reactivity following serum fractionation.

METHODS

Serum samples from 82 patients with cirrhosis were analyzed. SCCA-IgM was measured using the reference test (Hepa-IC, Xeptagen, Italy) that is based on rabbit oligoclonal anti-squamous cell carcinoma antigen (SCCA) and a dedicated ELISA with a mouse monoclonal anti-SCCA as the capture antibody.

RESULTS

SCCA-IgM concentrations measured with the reference assay (median value=87 AU/mL) were higher than those measured with the mouse monoclonal test (median value=78 AU/mL). However, the differences in the SCCA-IgM distribution were not statistically significant (p>0.05). When SCCA-IgM concentrations measured with both tests were compared, a linear correlation was found (r=0.77, p<0.05). Fractionation of the most reactive sera by gel-filtration chromatography showed that total recovery of SCCA-IgM reactivity was seen only in the fractions corresponding to components with a molecular weight higher than IgM and SCCA (>2000 kDa) with both tests.

CONCLUSIONS

The equivalence of both SCCA-IgM assays and the absence of reactivity not related to immune complexes support the analytical specificity of SCCA-IgM measurements. The results validate the assessment of SCCA-IgM for prognostic purposes in patients with cirrhosis.

Concepts and ways to amplify the antitumor immune response

In this chapter, a detailed description of how the innate and adaptive immune responses interact with malignant cells is presented. In addition, we discuss how developing tumors establish themselves, and how they benefit on one hand and organize their defense against the immune system on the other hand. New data from three tumor model systems in mice are discussed; in particular, the intricate interactions between the immune cells and the tumor cells are highlighted. With the present data and knowledge, we conclude that a first prerequisite for the combat against tumors is the activation of the innate immune system via external danger signals or damage signals and internal danger signals. The second prerequisite for efficient tumor cell eradication is combined therapeutic approaches of physical, chemical, pharmacological, and immunological origin. Finally, we propose new ways for further investigation of the relationship linking tumor cells and our defense system. It appears mandatory to understand how the malignant cells render the adaptive immune cells tolerant instead of turning them into aggressive effectors and memory cells. Perhaps, the most important thing, for immunologists and clinicians, to understand is that tumor cells must not be viewed just as antigens but much more.