Tumour infiltrating lymphocytes correlate with improved survival in patients with oesophageal adenocarcinoma.

BACKGROUND: Oesophageal adenocarcinoma (OAC) is increasingly common in the west, and survival remains poor at 10-15 % at 5 years. Immune responses are increasingly implicated as a determining factor of tumour progression. The ability of lymphocytes to recognise tumour antigens provides a mechanism for a host immune attack against cancer providing a potential treatment strategy. MATERIALS AND METHODS: Tumour infiltrating lymphocytes (TILs: CD3+, CD4+, CD8+ and FOXp3+) were assessed by immunohistochemistry using tissue microarrays in a contemporary and homogeneous cohort of OAC patients (n = 128) undergoing curative treatment. RESULTS: Multivariate analysis identified three independent prognostic factors for improved cancer-specific survival (CSS): increased CD8+ TILs (p = 0.003), completeness of resection (p < 0.0001) and lower pathological N stage (p < 0.0001). Independent prognostic factors for favourable disease-free survival included surgery-only treatment (p = 0.015), completeness of resection (p = 0.001), increased CD8+ TILs (p < 0.0001) and reduced pathological N stage (p < 0.0001). Higher levels of TILs in the pathological specimen were associated with significant pathological response to neoadjuvant chemotherapy (NAC). On multivariate analysis increased levels of CD4+ (p = 0.017) and CD8+ TILs (p = 0.005) were associated with significant local tumour regression and lymph node downstaging, respectively. DISCUSSION: Our results establish an association of TILs and survival in OAC, as seen in other solid tumours, and identify particular TIL subsets that are present at higher levels in patients who responded to NAC compared to non-responders. These findings highlight potential therapeutic strategies in EAC based on utilising the host immunological response and highlight the immune responses biomarker potential.

Rectal cancer staging post neoadjuvant therapy--how should the changes be assessed?

AIMS: To compare the utility and reproducibility of tumour regression grade scoring systems during histopathological assessment of rectal cancers resected after neoadjuvant (i.e. pre-operative) chemoradiotherapy. METHODS AND RESULTS: The histopathological features of tumour regression were assessed independently in 54 rectal cancer resection specimens using three scoring systems: the Tumour Regression Grade (TRG), modified Rectal Cancer Regression Grade (m-RCRG) and RCPath Cancer Dataset (RCPath) methods. Good interobserver agreement was achieved for all three systems (kappa scores: TRG system 0.719, m-RCRG system 0.734, RCPath system 0.742). Both observers diagnosed complete tumour regression and little/no regression in 11 cases (20% of all cases) and four cases (11% of all cases), respectively. A mean of 5.6 tumour blocks/case were taken and the mean lymph node yield was 8.4/case. CONCLUSIONS: All three scoring systems were usable in a diagnostic setting. The clinical significance of differing degrees of tumour regression is not yet universally agreed and, with this in mind, the m-RCRG system provided the optimum balance between applicability and the accurate recording of low, moderate and high degrees of tumour regression, thus facilitating future clinicopathological studies of moderate and high degrees of tumour regression and clinical outcome.

Viral fusogenic membrane glycoproteins kill solid tumor cells by nonapoptotic mechanisms that promote cross presentation of tumor antigens by dendritic cells.

Expression of viral fusogenic membrane glycoproteins (FMGs) is a potent strategy for antitumor cytotoxic gene therapy in which tumor cells are fused into large multinucleated syncytia. To understand how local cell killing can potentiate activation of antitumor immune responses, we characterized the mechanism of FMG-mediated cell killing. Here, we show that syncytia are highly ordered structures over 24-48 h but then die through processes that, by multiple morphological and biochemical criteria, bear very little resemblance to classical apoptosis. Death of syncytia is associated with nuclear fusion and premature chromosome condensation as well as severe ATP depletion and autophagic degeneration, accompanied by release of vesicles reminiscent of exosomes (syncytiosomes). Dying syncytia produce significantly more syncytiosomes than normal cells or cells killed by irradiation, freeze thaw, or osmotic shock. These syncytiosomes also load dendritic cells (DCs) more effectively than exosomes from cells dying by other mechanisms. Finally, we demonstrate that syncytiosomes from either autologous or allogeneic fusing melanoma cells lead to cross-presentation of a defined tumor antigen, gp100, by DCs to a gp100-specific CTL clone. Cross-presentation was significantly more efficient than that with exosomes from normal, irradiated, or herpes simplex virus thymidine kinase/ganciclovir-killed tumor cells. Therefore, FMG-mediated cell killing combines very effective local tumor cell killing with the potential to be a highly immunogenic method of cytotoxic gene therapy. In addition, these data open the way for novel methods of loading DCs with relevant tumor-associated antigens for vaccine development.

The role of systemic inflammatory and nutritional blood-borne markers in predicting response to neoadjuvant chemotherapy and survival in oesophagogastric cancer.

The aim of this study was to interrogate whether blood-borne inflammatory and nutritional markers predict long-term survival and response to neoadjuvant chemotherapy in radically treated oesophagogastric cancer patients. This retrospective study included 246 patients who underwent oesophageal resection for high-grade dysplasia or carcinoma between 2005 and 2010. The predictive value of routine preoperative immunonutritional blood tests was assessed for their association with survival and response to chemotherapy. On multivariate analysis, higher neutrophil-lymphocyte ratio (NLR) (p < 0.0001), N stage (p < 0.0001) and perineural invasion (p < 0.0001) were associated with poor overall survival. Regarding disease-free survival, multivariate analysis showed reduced serum albumin (p = 0.034), N stage (p < 0.0001), M stage (p = 0.037), vascular invasion (p < 0.0001) and presence of R1 resection (p = 0.003) to correlate with earlier recurrence. In those who received neoadjuvant chemotherapy, analysis of prechemotherapy characteristics showed only serum albumin (p = 0.037) to predict pathological response to chemotherapy. Preoperative immunonutritional markers, NLR and albumin, were independent prognostic markers for overall survival and disease-free survival, respectively, after oesophageal cancer resection. Prospective studies evaluating the role of immunonutritional modulation to improve response to chemotherapy and long-term outcome are required.

Refining pathological evaluation of neoadjuvant therapy for adenocarcinoma of the esophagus.

AIM: To assess tumour regression grade (TRG) and lymph node downstaging to help define patients who benefit from neoadjuvant chemotherapy. METHODS: Two hundred and eighteen consecutive patients with adenocarcinoma of the esophagus or gastro-esophageal junction treated with surgery alone or neoadjuvant chemotherapy and surgery between 2005 and 2011 at a single institution were reviewed. Triplet neoadjuvant chemotherapy consisting of platinum, fluoropyrimidine and anthracycline was considered for operable patients (World Health Organization performance status ≤ 2) with clinical stage T2-4 N0-1. Response to neoadjuvant chemotherapy (NAC) was assessed using TRG, as described by Mandard et al. In addition lymph node downstaging was also assessed. Lymph node downstaging was defined by cN1 at diagnosis: assessed radiologically (computed tomography, positron emission tomography, endoscopic ultrasonography), then pathologically recorded as N0 after surgery; ypN0 if NAC given prior to surgery, or pN0 if surgery alone. Patients were followed up for 5 years post surgery. Recurrence was defined radiologically, with or without pathological confirmation. An association was examined between t TRG and lymph node downstaging with disease free survival (DFS) and a comprehensive range of clinicopathological characteristics. RESULTS: Two hundred and eighteen patients underwent esophageal resection during the study interval with a mean follow up of 3 years (median follow up: 2.552, 95%CI: 2.022-3.081). There was a 1.8% (n = 4) inpatient mortality rate. One hundred and thirty-six (62.4%) patients received NAC, with 74.3% (n = 101) of patients demonstrating some signs of pathological tumour regression (TRG 1-4) and 5.9% (n = 8) having a complete pathological response. Forty four point one percent (n = 60) had downstaging of their nodal disease (cN1 to ypN0), compared to only 15.9% (n = 13) that underwent surgery alone (pre-operatively overstaged: cN1 to pN0), (P < 0.0001). Response to NAC was associated with significantly increased DFS (mean DFS; TRG 1-2: 5.1 years, 95%CI: 4.6-5.6 vs TRG 3-5: 2.8 years, 95%CI: 2.2-3.3, P < 0.0001). Nodal down-staging conferred a significant DFS advantage for those patients with a poor primary tumour response to NAC (median DFS; TRG 3-5 and nodal down-staging: 5.533 years, 95%CI: 3.558-7.531 vs TRG 3-5 and no nodal down-staging: 1.114 years, 95%CI: 0.961-1.267, P < 0.0001). CONCLUSION: Response to NAC in the primary tumour and in the lymph nodes are both independently associated with improved DFS.

Viral antigen mediated NKp46 activation of NK cells results in tumor rejection via NK-DC crosstalk.

Natural killer (NK) cells play a critical role in antitumor immunity, their activation being regulated through NK cell receptors. Although the endogenous ligands for these receptors are largely unknown, viral ligands have been identified. We investigated the ability of an activating NK receptor ligand derived from the mumps virus, haemagglutinin-neuraminidase (HN) to enhance NK activation against tumor cells. HN-expressing B16.OVA tumor cells induced stronger activation of NK cells compared with B16.OVA cells and also promoted dendritic cell (DC) activation toward a DC1 phenotype, in vitro. Moreover, incubation of DCs, NK cells and HN-expressing B16-OVA cells further enhanced NK cell activation through the NK-DC crosstalk, in a cell-to-cell contact- and IL-12-dependent fashion. Immunization of mice with HN-expressing B16-OVA cells resulted in > 85% survival rate after subsequent challenge with parental B16 or B16.OVA tumor cells. Tumor rejection was dependent on both NK and CD8+ T cells but not on CD4+ T cells, demonstrating induction of an effective adaptive immune response through innate immune cell activation. Our data indicate the potential of using robust NK cell activation, which through the NK-DC crosstalk stimulates effective antitumor responses, providing an alternate vaccine strategy.

Hanging in the balance. KIR and their role in disease.

The killer cell immunoglobulin-like receptors (KIR) are a recently discovered family of activating and inhibitory receptors that control natural killer (NK) cell function. KIR exist as a diverse family of receptors that have evolved rapidly by both gene duplication and recombination events. These findings were unexpected for a family of genes involved primarily in the innate immune response. These findings together with the observation that several of these genes have human leukocyte antigen (HLA) class I ligands, have led to a flurry of investigation into how KIR participate in viral infections, autoimmune diseases and malignancies. This review summarizes the major features of these genes and discusses how they may be involved in both disease pathogenesis and its amelioration.

Lack of specificity of cell-surface protease targeting of a cytotoxic hyperfusogenic gibbon ape leukaemia virus envelope glycoprotein.

BACKGROUND: In a strategy termed "Protease Targeting", retroviral vectors carrying an EGF infectivity-blocking domain fused to the N-terminus of the envelope SU via a MMP (matrix metalloproteinase)-cleavable linker were successfully used to target gene delivery to EGF receptor-(EGF-R-)positive tumour cells over-expressing MMPs. In the current study, we aimed to investigate whether this strategy could be applied to (a) limit the cytotoxic activity of a hyperfusogenic GALV therapeutic gene, and (b) enhance the immune-stimulatory properties of GALV via local, MMP-mediated release human granulocyte-macrophage colony stimulating factor (GM-CSF). METHODS: We generated GALV envelope expression constructs displaying EGF or GM-CSF blocking ligands at the N-terminus of GALV envelope SU via a non-cleavable, Factor Xa protease or MMP-cleavable linker and investigated their cytotoxicity on MMP-positive and negative cell lines. RESULTS: The unmodified hyperfusogenic GALV envelope was cytotoxic to all cell lines tested. The non-cleavable linker GALV envelope constructs caused no cytotoxicity, demonstrating efficient inhibition by the displayed domains. Moderate activation of fusion of the protease-cleavable linker constructs was observed in all cell lines, regardless of their level of MMP expression and of the specificity of the linker. High levels of the 'blocking domain' were detected in the cell supernatants due to dissociation of the surface unit (SU) from the transmembrane (TM) component of the GALV envelope glycoprotein TM. CONCLUSIONS: Unlike protease targeting in the context of retroviral vectors, protease activation of the cytotoxicity of GALV envelope by cleavage of a fusion blocking ligand at the cell surface does not appear to be specifically mediated by cell-surface MMPs. In addition, shedding of the SU-fusion protein from the TM limits the general applicability of this strategy for cancer gene therapy. Specificity of cell-cell fusion mediated by GALV envelope cannot be manipulated in the same fashion as virus-cell fusion.