Johan H. J. M. van Krieken

Toll-Like Receptor 2 Suppresses Immunity against Candida albicans through Induction of IL-10 and Regulatory T Cells

Toll-like receptor (TLR) 2 and TLR4 play a pivotal role in recognition of Candida albicans. We demonstrate that TLR2−/− mice are more resistant to disseminated Candida infection, and this is associated with increased chemotaxis and enhanced candidacidal capacity of TLR2−/− macrophages. Although production of the proinflammatory cytokines TNF, IL-1α, and IL-1β is normal, IL-10 release is severely impaired in the TLR2−/− mice. This is accompanied by a 50% decrease in the CD4+CD25+ regulatory T (Treg) cell population in TLR2−/− mice. In vitro studies confirmed that enhanced survival of Treg cells was induced by TLR2 agonists. The deleterious role of Treg cells on the innate immune response during disseminated candidiasis was underscored by the improved resistance to this infection after depletion of Treg cells. In conclusion, C. albicans induces immunosuppression through TLR2-derived signals that mediate increased IL-10 production and survival of Treg cells. This represents a novel mechanism in the pathogenesis of fungal infections.

Platinum-based drugs disrupt STAT6-mediated suppression of immune responses against cancer in humans and mice

Tumor microenvironments feature immune inhibitory mechanisms that prevent T cells from generating effective antitumor immune responses. Therapeutic interventions aimed at disrupting these inhibitory mechanisms have been shown to enhance antitumor immunity, but they lack direct cytotoxic effects. Here, we investigated the effect of cytotoxic cancer chemotherapeutics on immune inhibitory pathways. We observed that exposure to platinum-based chemotherapeutics markedly reduced expression of the T cell inhibitory molecule programmed death receptor-ligand 2 (PD-L2) on both human DCs and human tumor cells. Downregulation of PD-L2 resulted in enhanced antigen-specific proliferation and Th1 cytokine secretion as well as enhanced recognition of tumor cells by T cells. Further analysis revealed that STAT6 controlled downregulation of PD-L2. Consistent with these data, patients with STAT6-expressing head and neck cancer displayed enhanced recurrence-free survival upon treatment with cisplatin-based chemoradiation compared with patients with STAT6-negative tumors, demonstrating the clinical relevance of platinum-induced STAT6 modulation. We therefore conclude that platinum-based anticancer drugs can enhance the immunostimulatory potential of DCs and decrease the immunosuppressive capability of tumor cells. This dual action of platinum compounds may extend their therapeutic application in cancer patients and provides a rationale for their use in combination with immunostimulatory compounds.

Endogenous Interleukin (IL)–1α and IL-1β Are Crucial for Host Defense against Disseminated Candidiasis

BACKGROUND: Interleukin (IL)-1 alpha and IL-1 beta are protective proinflammatory cytokines involved in host defense against Candida albicans. It is, however, unknown whether they provide protection through similar mechanisms. We investigated the effect of endogenous IL-1 alpha and IL-1 beta on disseminated C. albicans infection. METHODS: Mice deficient in the genes encoding IL-1 alpha (IL-1 alpha-/-), IL-1 beta (IL-1 beta-/-), or both molecules (IL-1 alpha-/- beta-/-) were used. Survival and C. albicans outgrowth in the kidneys was assessed after intravenous injection of C. albicans. RESULTS: Both mortality and C. albicans outgrowth in the kidneys were significantly increased in IL-1 alpha-/- and IL-1 beta-/- mice, compared with those in control mice, with the IL-1 alpha-/- beta-/- mice being most susceptible to disseminated candidiasis. The host defense mechanisms triggered by IL-1 alpha and IL-1 beta differed from one another. IL-1 beta-/- mice showed decreased recruitment of granulocytes in response to an intraperitoneal C. albicans challenge, and generation of superoxide production was diminished in IL-1 beta-/- granulocytes. IL-1 alpha-/- mice had a reduced capacity to damage C. albicans pseudohyphae. Protective type 1 responses were deficient in both IL-1 alpha-/- and IL-1 beta-/- mice, as assessed by production of interferon-gamma by splenocytes in response to heat-killed C. albicans. CONCLUSION: Although IL-1 alpha and IL-1 beta have differential effects on the various arms of host defense, both cytokines are essential for mounting a protective host response against invasive C. albicans infection.

Ki-67 as a prognostic marker in mantle cell lymphoma—consensus guidelines of the pathology panel of the European MCL Network

Mantle cell lymphoma (MCL) has a heterogeneous clinical course and is mainly an aggressive B cell non-Hodgkin lymphoma; however, there are some indolent cases The Ki-67 index, defined by the percentage of Ki-67-positive lymphoma cells on histopathological slides, has been shown to be a very powerful prognostic biomarker. The pathology panel of the European MCL Network evaluated methods to assess the Ki-67 index including stringent counting, digital image analysis, and estimation by eyeballing. Counting of 2 × 500 lymphoma cells is the gold standard to assess the Ki-67 index since this value has been shown to predict survival in prospective randomized trials of the European MCL Network. Estimation by eyeballing and digital image analysis showed a poor concordance with the gold standard (concordance correlation coefficients [CCC] between 0.29 and 0.61 for eyeballing and CCC of 0.24 and 0.37 for two methods of digital image analysis, respectively). Counting a reduced number of lymphoma cells (2 × 100 cells) showed high interobserver agreement (CCC = 0.74). Pitfalls of the Ki-67 index are discussed and guidelines and recommendations for assessing the Ki-67 index in MCL are given.

Lymph Node Retrieval in Rectal Cancer is Dependent on Many Factors-the Role of the Tumor, the Patient, the Surgeon, the Radiotherapist, and the Pathologist

Lymph node status is the strongest prognostic factor for survival in colorectal cancer. There are several guidelines concerning the minimum numbers of lymph nodes that need to be examined to make reliable staging possible, but there is no consensus in the available literature. In this study, we determine in patients with rectal cancer factors that relate to the number of lymph nodes found and the presence of lymph node metastasis. In addition, the number of examined lymph nodes was correlated with prognosis. A total of 1227 patients were selected from a multicenter prospective randomized trial investigating the value of neoadjuvant radiotherapy. The median number of examined lymph nodes in all patients was 7.0. The number of retrieved lymph nodes in patients with node metastasis was significantly higher than in node negative patients. After neoadjuvant radiotherapy fewer lymph nodes were retrieved (6.9 vs. 8.5; P<0.0001). Variations in lymph node yield between pathology laboratories and individual pathologists were striking. The following patient and tumor characteristics are associated with a significant lower lymph node retrieval: age over 60 years, overweight, small size, and low invasion depth of the tumor, poor differentiation grade, and absence of a lymphoid reaction. Node negative patients in whom seven or less lymph nodes were examined had a lower recurrence free interval than patients in whom at least 8 lymph nodes were examined (17.0% vs. 10.7%, P=0.016). We conclude that in pathology laboratories a median of at least 8 lymph nodes need to be examined in rectal cancer specimens, but that higher numbers are desirable and achievable in most cases, even after preoperative radiotherapy.

A review on the use of molecular markers of cytotoxic therapy for colorectal cancer, what have we learned?

BACKGROUND Over the past decades, significant progress has been achieved in the cytotoxic treatment of colorectal cancer (CRC) by the use of fluoropyrimidines, irinotecan and oxaliplatin. However, as not all patients do respond to chemotherapy, there is a need for predictive and prognostic factors in order to optimise the treatment for individual patients. Although many potential molecular markers have been studied, none of these have been implemented in the standard of care for colorectal cancer patients. METHOD We performed a review of the data on the prognostic and/or predictive value of molecular markers for cytotoxic drugs in CRC. The following markers were included: dihydropyrimidine dehydrogenase, orotate phosphoribosyl transferase, thymidine phosphorylase, thymidylate synthase, mismatch repair deficiency, topoisomerase 1, excision cross-complementing gene and carboxylesterases. RESULTS With the exception of mismatch repair deficiency, these molecular markers showed divergent and inconsistent results on their prognostic and/or predictive value. This underscores the complexity of the role of these markers. CONCLUSIONS We conclude that further retrospective testing of these markers is unlikely to add clinically useful results. More definite results may only be expected when these markers are included in the design of prospective randomised studies.

High sensitivity of both sequencing and real-time PCR analysis of KRAS mutations in colorectal cancer tissue.

The KRAS mutation status predicts the outcome of treatment with epidermal growth factor receptor targeted agents, and therefore the testing for KRAS mutations has become an important diagnostic procedure. To optimize the quality of this test, we compared the results of the two most commonly used KRAS mutation tests, cycle sequencing and a real‐time PCR‐based assay, in DNA extracted from formalin‐fixed paraffin‐embedded (FFPE) colorectal cancer samples of 511 patients. The results were interpreted in the context of the tumour cell percentage and the assay parameters. In 510 samples KRAS mutation status assessment was successful. A KRAS mutation was detected in 201 tumours (39.4%). Sequencing and the real‐time PCR‐based assay generated the same result in 486 samples (95.3%). The sequencing result was considered false positive in one (0.2%) and false negative in nine samples (1.8%). The assay result was considered false positive in six (1.2%) and false negative in seven samples (1.4%). Explanations for discrepant test results were a higher sensitivity of the assay in samples with a low tumour cell percentage, occurrence of mutations that are not covered by the assay and δ Ct values approximating the cut‐off value of the assay. In conclusion, both sequencing and the real‐time PCR‐based assay are reliable tests for KRAS mutation analysis in FFPE colorectal cancer samples, with a sensitivity of 95.5% (95% confidence interval [CI] 91.7–97.9%) and 96.5% (95% CI 93.0–98.6%), respectively. The real‐time PCR based assay is the method of choice in samples with a tumour cell percentage below 30%.

Predictive and prognostic markers for the outcome of chemotherapy in advanced colorectal cancer, a retrospective analysis of the phase III randomised CAIRO study

We have tested several biomarkers [dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT), thymidine phosphorylase (TP), thymidylate synthase (TS) and excision cross-complementing gene (ERCC1)] for their prognostic and predictive value in relation to the outcome of chemotherapy in tumour tissues of 556 advanced colorectal cancer (ACC) patients who were randomised between sequential treatment and combination treatment in the CApecitabine, IRinotecan, Oxaliplatin (CAIRO) study. DPD expression showed a statistically significant predictive value for combination treatment with capecitabine plus irinotecan with low versus high values resulting in an improved median progression-free survival (PFS) and median overall survival (OS) of 8.9 (95% confidence interval (CI) 8.3-9.9) versus 7.2 months (95% CI 6.5-8.1, p=0.006), and 21.5 months (95% CI 17.9-26.5) versus 16.9 months (95% CI 13.0-19.1, p=0.04), respectively. In the overall patient population a high OPRT expression in stromal cells was a favourable prognostic parameter for OS, with 21.5 months (95% CI 17.9-27.3) versus 17.2 months (95% CI 15.1-18.6, p=0.036), respectively. A similar effect was observed for PFS. In a multivariate analysis that included known prognostic factors these results remained significant and also showed that a high OPRT expression in tumour cells was an unfavourable prognostic parameter for PFS and OS. In conclusion, in this largest study on capecitabine with or without irinotecan to date we found a predictive value of DPD expression. Our results on the prognostic value of OPRT expression warrant further studies on the role of stromal cells in the outcome of treatments. The divergent results of ours and previous studies underscore the complexity of these biomarkers and currently prevent the routine use of these markers in daily clinical practice.

Correlation of FCGR3A and EGFR germline polymorphisms with the efficacy of cetuximab in KRAS wild-type metastatic colorectal cancer.

BACKGROUND Next to KRAS mutation status, additional predictive markers are needed for the response to cetuximab in patients with metastatic colorectal cancer (mCRC). Previous studies indicated that germline polymorphisms in specific genes may predict efficacy and toxicity of cetuximab in mCRC patients. METHODS Germline DNA was isolated from 246 KRAS wild-type mCRC patients who were treated in the phase III CAIRO2 study with chemotherapy and bevacizumab alone or with the addition of cetuximab. Associations of epidermal growth factor (EGF) 61A>G, EGF receptor (EGFR) CA(14-22), cyclin D1 (CCND1) 932G>A, fragment-C gamma receptor (FCGR) 2A 535A>G and FCGR3A 818A>C polymorphisms with progression-free survival (PFS) and cetuximab-related skin toxicity were studied. RESULTS In cetuximab-treated patients, the FCGR3A 818C-allele was associated with decreased PFS compared with the FCGR3A 818AA genotype (median PFS, 8.2 [95%CI, 6.7-10.3] versus 12.8 [95%CI, 10.3-14.7] months, respectively; HR, 1.57 [95%CI, 1.06-2.34]; P=.025). The EGFR20 genotype was associated with decreased PFS compared with the EGFR<20 genotype (median PFS, 7.6 [95%CI, 6.7-10.0] versus 12.4 [95%CI, 10.3-13.4] months, respectively; HR, 1.58 [95%CI, 1.06-2.35]; P=.024). The FCGR3A and EGFR polymorphisms were not associated with PFS in patients treated without cetuximab. None of the polymorphisms were associated with the incidence of grades 2-3 skin toxicity. CONCLUSION EGFR and FCGR3A germline polymorphisms are associated with PFS in KRAS wild-type mCRC patients treated with cetuximab, bevacizumab and chemotherapy.

Intratumoral Recombinant Human Interleukin-12 Administration in Head and Neck Squamous Cell Carcinoma Patients Modifies Locoregional Lymph Node Architecture and Induces Natural Killer Cell Infiltration in the Primary Tumor

The objective of this study was to evaluate the histologic and immunohistopathologic effects of intratumorally given recombinant human interleukin-12 on the immune cells in the primary tumors and regional lymph nodes. Ten previously untreated patients with head and neck squamous cell carcinoma (HNSCC) were injected in the primary tumor twice to thrice, once weekly, at two dose levels of 100 or 300 ng/kg, before surgery. These patients were compared with 20 non-IL-12-treated control HNSCC patients. In the primary tumor, the number of CD56+ natural killer (NK) cells was increased in IL-12-treated patients compared with control patients. In some IL-12-treated patients, an impressive peritumoral invasion of CD20+ B cells was noticed. No differences were seen in the CD8+ or CD4+ T lymphocytes. Interestingly, major differences were apparent in the architecture of the enlarged lymph nodes of IL-12-treated patients; in particular, the distribution of B cells differed and fewer primary and secondary follicles with smaller germinal centers were observed. In addition, a decrease of dendritic cell lysosyme-associated membrane glycoprotein–positive cells in the paracortex was noted, resulting in a reduction of paracortical hyperplasia. In the lymph nodes, especially the CD56+ NK cells but also the CD8+ and CD4+ T lymphocytes, produced a high amount of IFN-γ. Patients, irrespectively of IL-12 treatment, with a high number of CD56+ cells in the primary tumor had a better overall survival than those with a low number. In conclusion, after i.t. IL-12 treatment in HNSCC patients, the largest effect was seen on the NK cells, with a higher number in the primary tumor and a high IFN-γ mRNA expression in the lymph nodes. Significant effects were noted on B cells, with altered lymph node architecture in every IL-12-treated patient and excessive peritumoral infiltration in some patients.