Radiochemotherapy induces a favourable tumour infiltrating inflammatory cell profile in head and neck cancer

Neoadjuvant Radiochemotherapy Alters the Immune and Metabolic Microenvironment in Oral Cancer-Analyses of CD68, CD163, TGF-β1, GLUT-1 and HIF-1α Expressions

BACKGROUND

The first-line treatment of oral squamous cell carcinoma (OSCC) involves surgical tumor resection, followed by adjuvant radio(chemo)therapy (R(C)T) in advanced cases. Neoadjuvant radio- and/or chemotherapy has failed to show improved survival in OSCC. Recently, neoadjuvant immunotherapy has shown promising therapeutic efficacy in phase 2 trials. In this context, the addition of radio- and chemotherapy is being reconsidered. Therefore, a better understanding of the tumor-biologic effects of neoadjuvant RCT would be beneficial. The current study was conducted on a retrospective cohort of patients who received neoadjuvant RCT for the treatment of oral cancer. The aim of the study was to evaluate the influence of neoadjuvant RCT on the immunological tumor microenvironment (TME) and hypoxic and glucose metabolisms.

METHODS

A cohort of 45 OSSC tissue samples from patients were analyzed before and after RCT (total 50.4 Gy; 1.8 Gy 5× weekly; Cisplatin + 5-Fluorouracil). Immunohistochemistry for CD68, CD163, TGF-β, GLUT-1 and HIF-1α was performed using tissue microarrays and automated cell counting. Differences in expression before and after RCT and associations with histomorphological parameters (T-status, N-status) were assessed using the Mann-Whitney U test.

RESULTS

Tumor resection specimens after neoadjuvant RCT showed a significant decrease in CD68 infiltration and a significant increase in CD163 cell density. The CD68/CD163 ratio was significantly lower after RCT, indicating a shift toward M2 polarization. The GLUT-1 and HIF-1α expressions were significantly lower after RCT. Larger tumors (T3/T4) showed a lower GLUT-1 expression. Other biomarkers were not associated with the T- and N-status.

CONCLUSIONS

Neoadjuvant RCT with 50.4 Gy induced a shift toward the M2 polarization of macrophages in the TME. This change in immune composition is not favorable and may be prognostically negative and counteract immunotherapeutic approaches. In addition, the decreased expressions in GLUT-1 and HIF-1α indicate reductions in the glucose metabolism and hypoxic energy metabolism in response to "high dose" neoadjuvant RCT, which may be therapeutically desirable.

Neutrophils in HNSCC Can Be Associated with Both a Worse or Favorable Prognosis

The prognostic significance of tumor-infiltrating neutrophils in head and neck squamous cell carcinoma (HNSCC) is poorly understood. It is unclear how the presence of neutrophils affects prognosis due to their polarization into cytotoxic N1 or immunosuppressive N2. Therefore, we determined the number of CD66b+ neutrophil granulocytes separately in the stromal and epithelial compartments in cancer tissues from 397 patients with HNSCC. Tumor samples from six historical patient groups were processed into tissue microarrays and stained immunohistochemically. In total, 21.9% were HPV positive (p16+). Neutrophil counts were much lower in the stromal compartment (372 ± 812) than in the epithelial cancer compartment (1040 ± 1477) (p < 0.001), with large differences between groups. In three groups with high neutrophil infiltration, high rates were associated with a favorable prognosis, whereas in two groups, high rates were a negative prognostic factor. In p16- oropharyngeal and hypopharyngeal cancer high infiltration was associated with a favorable prognosis. Cancers with an exclusion of neutrophils in the epithelial compartment were associated with improved prognosis. In oropharyngeal and hypopharyngeal HPV-negative cancer high neutrophil infiltration rates were clearly associated with prolonged survival. Neutrophil granulocytes in HNSCC may contribute to a favorable or unfavorable prognosis.

Modulation of CD8+ T Cell Responses by Radiotherapy-Current Evidence and Rationale for Combination with Immune Checkpoint Inhibitors

Radiotherapy for cancer has been known to affect the responses of immune cells, especially those of CD8+ T cells that play a pivotal role in anti-tumor immunity. Clinical success of immune checkpoint inhibitors led to an increasing interest in the ability of radiation to modulate CD8+ T cell responses. Recent studies that carefully analyzed CD8+ T cell responses following radiotherapy suggest the beneficial roles of radiotherapy on anti-tumor immunity. In addition, numerous clinical trials to evaluate the efficacy of combining radiotherapy with immune checkpoint inhibitors are currently undergoing. In this review, we summarize the current status of knowledge regarding the changes in CD8+ T cells following radiotherapy from various preclinical and clinical studies. Furthermore, key biological mechanisms that underlie such modulation, including both direct and indirect effects, are described. Lastly, we discuss the current evidence and essential considerations for harnessing radiotherapy as a combination partner for immune checkpoint inhibitors.

Chemotherapy to potentiate the radiation-induced immune response

Chemoradiation (CRT) is a conventional therapy used in local cancers, especially when they are locally advanced. Studies have shown that CRT induces strong anti-tumor responses involving several immune effects in pre-clinical models and humans. In this review, we have described the various immune effects involved in CRT efficacy. Indeed, effects such as immunological cell death, activation and maturation of antigen-presenting cells, and activation of an adaptive anti-tumor immune response are attributed to CRT. As often described in other therapies, various immunosuppressive mechanisms mediated, in particular, by Treg and myeloid populations may reduce the CRT efficacy. We have therefore discussed the relevance of combining CRT with other therapies to potentiate the CRT-induced anti-tumor effects.

DNA methylation profiles differ in responders versus non-responders to anti-PD-1 immune checkpoint inhibitors in patients with advanced and metastatic head and neck squamous cell carcinoma

BACKGROUND

Biomarkers for response prediction to anti-programmed cell death 1 (PD-1) immune checkpoint inhibitors (ICI) in patients with head and neck squamous cell carcinoma (HNSCC) are urgently needed for a personalized therapy approach. We investigated the predictive potential of inflammatory parameters and DNA methylation profiling in patients with HNSCC treated with anti-PD-1 ICI.

METHODS

We identified patients with HNSCC that were treated with anti-PD-1 ICI therapy in the recurrent or metastatic setting after progression to platinum-based chemotherapy in two independent centers. We analyzed DNA methylation profiles of >850.000 CpG sites in tumor specimens of these patients by Infinium MethylationEPIC microarrays, immune cell density in the tumor microenvironment (CD8, CD3, CD45RO, forkhead box P3 (FOXP3), CD68), PD-1 and programmed cell death ligand 1 (PD-L1) expression by immunohistochemistry, and blood inflammation markers (platelet-to-lymphocyte ratio, leucocyte-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, neutrophil-to-lymphocyte ratio). DNA methylation profiles and immunological markers were bioinformatically and statistically correlated with radiological response to anti-PD-1 ICI.

RESULTS

37 patients with HNSCC (median age of 62 years; range 49-83; 8 (21.6%) women, 29 (78.4%) men) were included (Center 1 N=26, 70.3%; Center 2 N=11, 29.7%). Median number of prior systemic therapies was 1 (range 1-4). Five out of 37 (13.5%) patients achieved an objective response to ICI. Median progression-free survival and median overall survival times were 3.7 months (range 0-22.9) and 9.0 months (range 0-38.8), respectively. Microarray analyses revealed a methylation signature including both hypomethylation and hypermethylation which was predictive for response to ICI and included several genes involved in cancer-related molecular pathways. Over-represented differentially methylated genes between responders and non-responders were associated with 'Axon guidance', 'Hippo signaling', 'Pathways in cancer' and 'MAPK signaling'. A statistically significant correlation of PD-L1 expression and response was present (p=0.0498).

CONCLUSIONS

Our findings suggest that tumor DNA methylation profiling may be useful to predict response to ICI in patients with HNSCC.

Characterization of immune cell infiltrate in tumor stroma and epithelial compartments in oral squamous cell carcinomas of Sudanese patients

BACKGROUND

Tumor immune infiltrate has been explored in oral squamous cell carcinoma (OSCC), but studies on simultaneous characterization of multiple immune cell subtypes separately in stromal and intraepithelial tumor compartments are limited.

OBJECTIVES

We aimed to investigate the immune cell infiltrate in OSCC by using immunohistochemistry (IHC) for a panel of inflammatory cells in stromal and epithelial tumor compartments for a better characterization of the tumors.

METHODS

Thirty-six OSCC lesions and nine normal oral mucosa (NOM) samples from patients attending Khartoum Dental Teaching Hospital, Sudan were investigated for presence of tumor infiltrating lymphocytes, tumor-associated macrophages, tumor-associated neutrophils, and PD-L1 positive cells in the inflammatory infiltrate by single and double IHC. Digital quantitative analysis (Aperio Technologies Inc.) was performed separately for stromal and epithelial compartments.

RESULTS

OSCC cases displayed a higher inflammatory infiltrate in the associated stroma, but not in the epithelial compartment when compared to NOM. The immunosuppressive type of inflammatory infiltrate, that is, T regulatory cells (FoxP3⁺ cells) was identified to be significantly higher in the epithelial compartment of tumors with advanced clinical state. An immunoscore developed by combining intraepithelial FoxP3⁺ and CD4⁺ cells was found significantly higher in lesions from elderly patients, localized at toombak dipping-related sites, poorly differentiated OSCCs, or with loco-regional lymph node spreading.

CONCLUSIONS

Despite heavy immune cell infiltration in tumor-associated stroma, the majority of OSCCs in this cohort displayed a low intraepithelial immune infiltration. An immunoscore based on combined CD4 and FoxP3 intraepithelial expression may serve as an indicator of advanced tumor progression and should be further investigated for its use as potential prognostic biomarker in OSCC.

Infiltrative tumour growth pattern correlates with poor outcome in oesophageal cancer

Objective

Oesophageal cancer (OEC) is an aggressive disease with a poor survival rate. Prognostic markers are thus urgently needed. Due to the demonstrated prognostic value of histopathological growth pattern (HGP) in other cancers, we performed a retrospective assessment of HGP in patients suffering from invasive OEC.

Design

A first cohort composed of 89 treatment-naïve operated patients with OEC from The Cancer Genome Atlas (TCGA) public database was constituted, from which H&E images and RNA-sequencing data were retrieved. Next, a second cohort composed of 99 patients with OEC treated and operated in a Belgian hospital was established. H&E-stained sections and extracted tumorous RNA were obtained from the samples. HGP were assessed on H&E slides as infiltrative (IGP) or expansive (EGP). TCGA RNA-sequencing data were analysed through the gene set enrichment analysis and Cytoscape softwares. Real-time quantitative PCR (qPCR) experiments were performed to assess gene expression in the Belgian cohort.

Results

IGP patients displayed a grim prognosis compared with EGP patients, while IGP was found as associated with numerous lymphovascular emboli and perinervous infiltrations. Analyses of the TCGA expression data showed that angiogenesis, epithelial-to-mesenchymal transition (EMT) and inflammation were significantly upregulated in IGP compared with EGP samples. qPCR experiments of three genes appearing as highly upregulated in each pathway showed no difference in expression according to the HGP.

Conclusion

The current study demonstrates the poor prognostic value carried by IGP in OC and suggests angiogenesis, EMT and inflammation as key carcinogenetic pathways upregulated in this pattern.

The role of radiotherapy in the age of immunotherapy

With the development of immune checkpoint inhibitors, the efficacy of immunotherapy as a cancer treatment that is effective against multiple tumor types has been established, and this modality came to be considered as the fourth pillar of cancer therapy. The clinical success of immunotherapy greatly changed the field of oncology by highlighting the importance of the immune system in cancer control and elimination. It has now become clear that research into, and the clinical application of, the immune response are important for effective cancer treatment. Moreover, it has become apparent that conventional cancer treatments, such as radiotherapy and chemotherapy, can modulate the cross-talk between the tumor and the immune system, and their efficacy depends, in part, on the ability to elicit antitumor immune response. The ability of radiotherapy to induce an immune response has become relevant in the immunotherapy age. Radiotherapy has been redefined as a partner for cancer immunotherapy, based on evidence indicating the potential synergistic effect of the combination of these therapeutic modalities. This review outlines the major findings reported to date on the immune response induced by radiotherapy and discusses the role of radiotherapy in combination with immunotherapy. Furthermore, we introduce research aimed at the clinical application of combination therapy and discuss its potential in clinical practice and future issues.

Moderately differentiated esophageal squamous cell carcinoma has a poor prognosis after neoadjuvant chemoradiotherapy

Background

Neoadjuvant chemoradiotherapy (NCRT) plus surgery is the standard treatment for esophageal squamous cell carcinoma (ESCC); however, further analysis is needed to detail the histopathological characteristics of ESCC and their clinical significance after NCRT. This study aimed to present the pathological characteristics of ESCC and their association with prognosis after NCRT.

Methods

All patients with ESCC who underwent NCRT followed by surgical resection at Sichuan Cancer Hospital (China) from January 2018 to December 2019 were included. Resection specimens of both the primary disease and lymph nodes were re-evaluated by an experienced pathologist. After NCRT, the pathological characteristics of the residual tumor were evaluated based on the Japanese residual tumor pattern, Mandard tumor regression grade (Mandard-TRG), local inflammatory infiltration classification, and lymph node status.

Results

Among the 103 patients with ESCC included in this study, the pathological complete response (pCR) rate was 34% (35/103). The pCR rate of patients with poorly differentiated tumors (31/72) was higher (43.1%) than that of patients with well or moderately differentiated tumors (P<0.05). The residual tumor rate was 66% (68/103). A positive correlation was noted between the Japanese residual tumor pattern and Mandard-TRG (Kendall’s tau-b =0.857, P<0.001). Tumor infiltration depth, lymph node positivity, moderate differentiation, and tumor recurrence were associated with poor oncological outcomes (P<0.05).

Conclusions

Patients with poorly differentiated tumors can obtain an excellent short-term response; however, they have extremely poor long-term survival. For patients with moderately differentiated tumors, both the short- and long-term outcomes are poor. Lymph node status after NCRT is a prognostic factor for ESCC treated with NCRT.

Immune checkpoint expression in HNSCC patients before and after definitive chemoradiotherapy

BACKGROUND

Primary platinum-based chemoradiotherapy (CRT) remains the treatment of choice for nonresectable squamous cell carcinoma of the head and neck (HNSCC). Immune-checkpoint modulators are used as palliative therapy and studied in combination with definitive CRT. However, the immunological changes by CRT need yet to be understood.

METHODS

A cohort consisting of 67 paired tissue biopsies (N = 134) of HNSCC patients before and after CRT was created. The expression of PD-1, PD-L1, and CD27 of tumor and immune cells by immunohistochemistry was evaluated.

RESULTS

PD-L1 expression on immune cells of non-responders was significantly lower before CRT (P = .008). CD27 was expressed only on immune cells and not on cancer cells. A significant lower CD27-expression score was observed following CRT (P = .019).

CONCLUSIONS

Conventional CRT changes the expression of CD27 in the tumor microenvironment. Whether this is due to a loss of expression or a reduction of CD27+ cells must be evaluated in further analyses.

Onodera's prognostic nutritional index correlates with tumor immune environment and survival in patients with oral squamous cell carcinoma undergoing chemoradiotherapy

Pretreatment nutritional and immunological status is useful for predicting survival outcomes for various types of malignant tumors. Our objective was to determine the impact of the pretreatment Onodera's prognostic nutritional index (OPNI) on outcomes of patients who underwent definitive chemoradiotherapy for advanced oral squamous cell carcinoma (OSCC). We reviewed 47 patients treated for OSCC with definitive chemoradiotherapy (CRT) at our institution between January 2004 and December 2011. We determined the OPNI according to the following formula: 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count (per μL). We determined the optimum OPNI cut-off through a receiver operating characteristic analysis. We analyzed the associations between OPNI status and various clinicopathological features and evaluated the effects of OPNI on the prognosis. We examined the relationships between OPNI and systemic inflammatory response parameters and analyzed intratumoral CD8+ T cells and their correlation with OPNI. The optimum OPNI cut-off was 42.7. A Kaplan–Meier curve analysis revealed that low OPNI was significantly associated with poor overall survival and cause-specific survival. The multivariate analysis revealed that low OPNI was independently correlated with poor 5 year overall survival and cause-specific survival. OPNI was significantly correlated with systemic inflammatory response parameters. Intratumoral CD8+ T cell counts in primary tumors were significantly lower for low OPNI than for high OPNI. The present data demonstrate that pretreatment OPNI is a valuable independent prognostic indicator of overall and cause-specific survival in advanced OSCC following definitive CRT. OPNI might reflect the tumor immune microenvironment characterization in OSCC.

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The optimum Onodera's prognostic nutritional index (OPNI) cut-off was 42.7 in OSCC patients who underwent definitive chemoradiotherapy

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Low OPNI was significantly associated with poor overall survival and cause-specific survival

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OPNI was significantly correlated with systemic inflammatory response parameters

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High-OPNI group showed significantly higher intratumoral CD8+ T cell counts in primary tumors

Priming the tumor immune microenvironment with chemo(radio)therapy: A systematic review across tumor types

BACKGROUND

Chemotherapy (CT), radiotherapy (RT), and chemoradiotherapy (CRT) are able to alter the composition of the tumor immune microenvironment (TIME). Understanding the effect of these modalities on the TIME could aid in the development of improved treatment strategies. Our aim was to systematically review studies investigating the influence of CT, RT or CRT on different TIME markers.

METHODS

The EMBASE (Ovid) and PubMed databases were searched until January 2019 for prospective or retrospective studies investigating the dynamics of the local TIME in cancer patients (pts) treated with CT, RT or CRT, with or without targeted agents. Studies could either compare baseline and follow-up specimens - before and after treatment - or a treated versus an untreated cohort. Studies were included if they used immunohistochemistry and/or flow cytometry to assess the TIME.

RESULTS

In total we included 110 studies (n = 8850 pts), of which n = 89 (n = 6295 pts) compared pre-treatment to post-treatment specimens and n = 25 (n = 2555 pts) a treated versus an untreated cohort (4 studies conducted both comparisons). For several tumor types (among others; breast, cervical, esophageal, ovarian, rectal, lung mesothelioma and pancreatic cancer) remodeling of the TIME was observed, leading to a potentially more immunologically active microenvironment, including one or more of the following: an increase in CD3 or CD8 lymphocytes, a decrease in FOXP3 Tregs and increased PD-L1 expression. Both CT and CRT were able to immunologically alter the TIME.

CONCLUSION

The TIME of several tumor types is significantly altered after conventional therapy creating opportunities for concurrent or sequential immunotherapy.

Prognostic value of post-radiotherapy neutrophil-to-lymphocyte ratio in locally advanced nasopharyngeal carcinoma

PURPOSE

To explore the temporal profile of the peripheral neutrophil-to-lymphocyte ratio (NLR) in patients with locally advanced nasopharyngeal carcinoma (LANPC) and the potential prognostic value of its dynamic changes.

METHODS

Complete blood count of 112 patients from a previous phase II study were retrospectively collected at the timepoints of the initiation of induction chemotherapy (pre-IC), within 1 week before radiotherapy started (pre-RT), and within 1 week after radiotherapy finished (post-RT). Data of 103 patients were fully recorded and Cox regression analysis was used to analyze the correlations of potential risk factors with 5‑year overall survival (OS). The performance of the prognostic factor was validated in another independent cohort of 103 matched (by T and N stage) patients selected from 236 consecutive NPC patients treated with IC and concurrent chemoradiation.

RESULTS

Multivariate analysis (MVA) identified patient age >50 years old (hazard ratio [HR] = 3.4, p = 0.02), weight loss during RT >7.5% (HR = 3.2, p = 0.03), and post-RT peripheral NLR >7.05 (vs. NLR ≤7.05, HR = 2.5, p = 0.04, 5‑year OS 71.4% vs. 87.8%) as unfavorable prognostic factors for OS. There was also a non-significant trend in the MVA that patients with post-RT peripheral NLR >7.05 showed worse progression-free survival (PFS; HR = 1.9, p = 0.06, 5‑year PFS 64.1% vs. 81.8%). Post-RT NLR had a good prognostic performance in the validation cohort (concordance index = 0.73, standard error 0.10; p = 0.02, Wilcoxon test).

CONCLUSION

Post-RT NLR is an independent prognostic factor for OS in LANPC patients. The dynamic change of the routinely tested inflammatory variable could help selection of appropriate treatment options and follow-up strategies.

Metformin Effects on FOXP3+ and CD8+ T Cell Infiltrates of Head and Neck Squamous Cell Carcinoma

OBJECTIVES

Alterations of cellular metabolism have been implicated in immune dysfunction in the tumor microenvironment (TME) of head and neck squamous cell carcinoma (HNSCC). Metformin has recently emerged as a candidate of interest for combination with immunotherapy in HNSCC. This study investigated the effect of metformin on immune cell infiltrates of HNSCC.

METHODS

Retrospective analysis of T cell infiltrates in primary tumor specimens from patients enrolled in a clinical window of opportunity trial of presurgical metformin. Metformin was titrated to a standard diabetic dose (2000 mg/day) for a minimum of 9 days (mean 13.6 days) prior to surgical resection. Pre and posttreatment surgical specimens from 36 patients (16 HPV⁺ , 20 HPV^- ) were comparatively analyzed. FOXP3⁺ and CD8⁺ immune cell infiltrates in the tumor and peritumoral stroma of pre and posttreatment HNSCC specimens were quantified by digital image analysis using Visiopharm software.

RESULTS

Metformin treatment was associated with a 41.4% decrease in FOXP3⁺ T cells in intratumor regions of interest (P = .004) and a 66.5% increase in stromal CD8⁺ T cells at the leading edge of the tumor (P = .021) when compared to pretreatment biopsies. This was reflected in increased CD8⁺ /FOXP3⁺ cell ratios within the tumor (P < .001) and stromal compartments (P < .001). The effects of metformin occurred independently of HPV status.

CONCLUSION

Metformin treatment may favorably alter the immune TME in HNSCC independent of HPV status.

LEVEL OF EVIDENCE

1b. This study is most accurately described as a non-randomized controlled trial and therefore may reflect a level of evidence below 1b but above 2a from the provided "levels of evidence" chart. Laryngoscope, 130:E490-E498, 2020.

CD8+ and Regulatory T cells Differentiate Tumor Immune Phenotypes and Predict Survival in Locally Advanced Head and Neck Cancer

Background: The tumor immune status “inflamed”, “immune excluded”, and “desert” might serve as a predictive parameter. We studied these three cancer immune phenotypes while using a simple immunohistochemical algorithm. Methods: Pre-treatment tissue samples of 280 patients with locally advanced HNSCC treated with radiochemotherapy were analyzed. A double staining of CD8+ cytotoxic T cells (CTL) and FoxP3+ (Treg) was performed and the cell density was evaluated in the intraepithelial and stromal compartment of the tumor. Results: The classification of tumors as “immune desert” when stromal CTL were ≤ 50 cells/mm², “inflamed” when intraepithelial CTL were > 500 cells/mm², and as “excluded” when neither of these definitions met these cut off values allowed the best discrimination regarding overall survival. These groups had median OS periods of 37, 61, and 85 months, respectively. In “immune desert” and “immune excluded” tumors high Treg tended to worsen OS, but in “inflamed” tumors high Treg clearly improved OS. Conclusions: We propose that, in locally advanced HNSCC, the tumor immune state “inflamed”, “immune excluded”, and “immune desert” can be defined by intraepithelial and stromal CTL. Tregs can further subdivide these groups. The opposing effects of Tregs in the different groups might be the reason for the inconsistency of Tregs prognostic values published earlier.

Computer-assisted image analysis of the tumor microenvironment on an oral tongue squamous cell carcinoma tissue microarray

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Tissue segmentation can be achieved using a spatially registered cytokeratin mask.

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Automated and manual cell counts and stain intensities were highly correlated.

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Smokers had significantly stronger PD-L1 stain intensity and higher numbers TILs.

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After radiotherapy, greater CD8+ TILs was associated with inferior survival.

Oral tongue squamous cell carcinoma (OTSCC) displays variable levels of immune cells within the tumor microenvironment. The quantity and localization of tumor infiltrating lymphocytes (TILs), specific functional TIL subsets (e.g., CD8+), and biomarker-expressing cells (e.g., PD-L1+) may have prognostic and predictive value. The purpose of this study was to evaluate the robustness and utility of computer-assisted image analysis tools to quantify and localize immunohistochemistry-based biomarkers within the tumor microenvironment on a tissue microarray (TMA). We stained a 91-patient OTSCC TMA with antibodies targeting CD3, CD4, CD8, FOXP3, IDO, and PD-L1. Cell populations were segmented into epithelial (tumor) or stromal compartments according to a mask derived from a pan-cytokeratin stain. Definiens Tissue Studio was used to enumerate marker-positive cells or to quantify the staining intensity. Automated methods were validated against manual tissue segmentation, cell count, and stain intensity quantification. Univariate associations of cell count and stain intensity with smoking status, stage, overall survival (OS), and disease-free survival (DFS) were determined. Our results revealed that the accuracy of automated tissue segmentation was dependent on the distance of the tissue section from the cytokeratin mask and the proportion of the tissue containing tumor vs. stroma. Automated and manual cell counts and stain intensities were highly correlated (Pearson coefficient range: 0.46–0.90; p < 0.001). Within this OTSCC cohort, smokers had significantly stronger PD-L1 stain intensity and higher numbers of CD3+, CD4+ and FOXP3+ TILs. In the subset of patients who had received adjuvant radiotherapy, a higher number of CD8+ TILs was associated with inferior OS and DFS. Taken together, this proof-of-principle study demonstrates the robustness and utility of computer-assisted image analysis for high-throughput assessment of multiple IHC markers on TMAs, with potential implications for studies on prognostic and predictive biomarkers.

Tumor-infiltrating CD8+ T-cell density is an independent prognostic marker for oral squamous cell carcinoma

BACKGROUND

The presence of tumor-infiltrating lymphocytes (TILs) is associated with improved survival in head and neck squamous cell carcinoma. However, the prognostic value of TILs remains unclear in oral squamous cell carcinoma (OSCC).

METHODS

We evaluated the associations between tumor-infiltrating CD8⁺ T-cell density and survival in five distinct compartments in 139 OSCC cases.

RESULTS

There was a significant association between increased tumor-infiltrating CD8⁺ T cells and their distribution. High parenchymal CD8⁺ T-cell density at the invading tumor edge was associated with improved overall survival (OS) and disease-specific survival (DSS; P < 0.01 and P < 0.01, respectively). High stromal CD8⁺ T-cell density at the tumor periphery was also associated with improved recurrence-free survival (RFS; P < 0.01). Cox regression analysis revealed that high stromal CD8⁺ T-cell density at the tumor periphery and high parenchymal CD8⁺ T-cell density at the invading edge were independent prognostic makers (hazard ratio: 0.38 and 0.19, 95% confidence interval, 0.18-0.80 and 0.05-0.72, P = 0.01 and 0.01, respectively) for RFS and OS, respectively.

CONCLUSIONS

Assessment of CD8⁺ T cells at the parenchyma of the invading edge and peripheral stroma provides an indicator of tumor recurrence and prognosis.

Utility of CD8 score by automated quantitative image analysis in head and neck squamous cell carcinoma

INTRODUCTION

In head and neck squamous cell carcinoma (HNSCC) high numbers of tumor infiltrating CD8 T cells in the tumor microenvironment are associated with better outcome. However, no investigators have employed automated image analysis on whole slide images to permit CD8 scores for use in clinical practice. The aim of this study was to develop and validate an image analysis algorithm to automatically quantify CD8 T cells in patients with oropharyngeal HNSCC.

MATERIALS AND METHODS

Using brightfield image analysis results were cross-validated with fluorescence based quantification (AQUA™). A nuclear image algorithm designed to run on whole slide images was optimized to manual count. The algorithm was locked down and used on a cohort of whole tissue sections from HNSCC patients. Multivariate clinicopathologic parameters and outcomes were statistically correlated with image analysis results.

RESULTS

Linear correlation between manual counts and the customized CD8 algorithm was 0.943. A total of 74 oropharyngeal HNSCC cases were analyzed for CD8 immune cell infiltrate using this image analysis algorithm. A CD8 immune cell density above 136 cells/mm² was associated with median survival of 18 years compared to 5 years. When multivariate modeling was performed, HPV infection was the only predictor of survival; however, when HPV was excluded only CD8 cell density predicts survival.

CONCLUSIONS

We report the successful technical development and clinical validation of an image algorithm to automate CD8 immune cell density for oropharyngeal HNSCC. Employing brightfield image analysis on entire tumor sections instead of tumor subcompartments permits this strategy to be widely implemented.

The role of regulatory T cells in pathogenesis and therapy of human papillomavirus-related diseases, especially in cancer

Human papillomavirus (HPV) is the most common sexually transmitted agent in the world. It can cause condyloma acuminatum, anogenital malignancies, and head and neck cancers. The host immune responses to HPV involve multiple cell types that have regulatory functions, and HPV-mediated changes to regulatory T cells (Tregs) in both the local lesion tissues and the circulatory system of patients have received considerable attention. The role of Tregs in HPV infections ranges from suppression of effector T cell (Teff) responses to protection of tissues from immune-mediated injury in different anatomic subsites. In this review, we explore the influence of Tregs in the immunopathology of HPV-related diseases and therapies targeting Tregs as novel approaches against HPV.

Radiation-Induced Transformation of Immunoregulatory Networks in the Tumor Stroma

The implementation of novel cancer immunotherapies in the form of immune checkpoint blockers represents a major advancement in the treatment of cancer, and has renewed enthusiasm for identifying new ways to induce antitumor immune responses in patients. Despite the proven efficacy of neutralizing antibodies that target immune checkpoints in some refractory cancers, many patients do not experience therapeutic benefit, possibly owing to a lack of antitumor immune recognition, or to the presence of dominant immunosuppressive mechanisms in the tumor microenvironment (TME). Recent developments in this field have revealed that local radiotherapy (RT) can transform tumors into in situ vaccines, and may help to overcome some of the barriers to tumor-specific immune rejection. RT has the potential to ignite tumor immune recognition by generating immunogenic signals and releasing neoantigens, but the multiple immunosuppressive forces in the TME continue to represent important barriers to successful tumor rejection. In this article, we review the radiation-induced changes in the stromal compartments of tumors that could have an impact on tumor immune attack. Since different RT regimens are known to mediate strikingly different effects on the multifarious elements of the tumor stroma, special emphasis is given to different RT schedules, and the time after treatment at which the effects are measured. A better understanding of TME remodeling following specific RT regimens and the window of opportunity offered by RT will enable optimization of the design of novel treatment combinations.

[Inflammatory and immune biomarkers of radiation response]

In radiotherapy, the treatment is adapted to each individual to protect healthy tissues but delivers most of time a standard dose according to the tumor histology and site. The only biomarkers studied to individualize the treatment are the HPV status with radiation dose de-escalation strategies, and tumor hypoxia with dose escalation to hypoxic subvolumes using FMISO- or FAZA-PET imaging. In the last decades, evidence has grown about the contribution of the immune system to radiation tumor response. Many preclinical studies have identified some of the mechanisms involved. In this context, we have realised a systematic review to highlight potential inflammatory and immune biomarkers of radiotherapy response. Some are inside the tumor microenvironment, as lymphocyte infiltration or PD-L1 expression, others are circulating biomarkers, including different types of hematological cells, cytokines and chemokines.

Spatial distribution of FoxP3+ and CD8+ tumour infiltrating T cells reflects their functional activity

BACKGROUND

Regulatory and cytotoxic T cells are key players in the host's anticancer immune response. We studied the spatial distribution of FoxP+ and CD8+ cells to identify potential interactions.

METHODS

In 202 patients 103 pre-radiochemotherapy biopsies and 153 post-radiochemotherapy tumour specimens of advanced rectal cancer were available and an immunohistochemical double staining of FoxP3+ and CD8+ tumour-infiltrating lymphocytes was performed to investigate cell density and cell-to-cell distances.

RESULTS

FoxP3+ cells decreased after radiochemotherapy by a factor of 3 while CD8+ cells remained nearly unchanged. High epithelial (p=0.033) and stromal (p=0.009) FoxP3+ cell density was associated with an improved overall survival. Cell-to-cell distances of randomly distributed cells were simulated and compared to observed cell-to-cell distances. Observed distances shorter than the simulated, random distances were hypothesized to represent FoxP3+ cells actively interacting with CD8+ cells. Epithelial short distances were associated with a favourable prognosis while the opposite was true for the stromal compartment.

CONCLUSION

The analysis of cell-to-cell distances may offer a tool to predict outcome, maybe by identifying functionally active, interacting infiltrating inflammatory cells in different tumour compartments.

Prognostic value of CD45 transcriptional expression in head and neck cancer

INTRODUCTION

Tumor-infiltrating lymphocytes (TILs) have a recognized antitumor activity in head and neck squamous cell carcinoma (HNSCC). CD45 is one of the most highly expressed proteins in lymphocytes. We carry out a study to assess the prognostic value of transcriptional expression of CD45 in HNSCC.

MATERIAL AND METHODS

We determined the transcriptional expression of CD45 in 160 consecutive HNSCC patients and compared the TIL values according to the CD45 expression.

RESULTS

Five-year disease-free survival for patients with a high transcriptional expression of CD45 (n = 107) was 62.4% and for patients with a low expression (n = 53) it was 36.2% (P = 0.003). Patients with a high expression of CD45 had a better local recurrence-free survival and disease-specific survival. The results of a multivariate analysis showed that patients with a low expression of CD45 had 2.0-fold high risk of recurrence (95% CI 1.2-3.2, P = 0.003). In oropharyngeal carcinomas, HPV-positive tumors showed a higher transcriptional CD45 expression than HPV-negative tumors. Tumors with high CD45 expression had immunohistochemical TIL scores significantly higher than those with low CD45 expression.

CONCLUSION

According to our results, CD45 expression is a potential marker for tumor outcome in HNSCC patients.

Prognostic impact of immune microenvironment in laryngeal and pharyngeal squamous cell carcinoma: Immune cell subtypes, immuno-suppressive pathways and clinicopathologic characteristics

Background

Immune system affects prognosis of various malignancies. Anti-immune pathways like PD-L1 and CTLA4 are used by the tumor to overcome immune system and they serve as immunotherapy targets. The immune microenvironment of head-and-neck squamous cell carcinoma (SCCHN) has not been sufficiently studied.

Patients and Methods

152 SCCHN were immunohistochemically studied for the expression of CD3, CD8, CD57, CD4, granzyme b, CD20, CD163, S100, PD-L1, CTLA4 and CXCR4.

Results

CD3, CD8, CD57 and stromal S100 higher density is a good prognostic factor (p=0.02, 0.01, 0.02, 0.03 respectively). CTLA4 tumor expression is a poor prognostic factor (p=0.05). The rest immune cells do not affect prognosis. CD3 and CD8 density does not correlate with clinicopathological factors or p16/p53 expression, while CD57 and CD4 higher density is associated with the absence of distant metastases (p=0.03 and 0.07, respectively). Higher CD20 and S100 density is associated with lower T stage (p=0.04 and 0.03, respectively). PD-L1 expression is higher in CD3, CD8, and CD163 infiltrated tumors and in histologically more aggressive tumors. Response to neoadjuvant chemotherapy is better in highly CD3 infiltrated tumors and in tumors with less intraepithelial macrophages.

Conclusion

Rich T-lympocytic and dendritic cell response is a good prognostic factor in SCCHN, whereas tumors expressing CTLA4 show poor prognosis. PDL1 expression does not affect prognosis, but it is expressed in histologically more aggressive tumors and in T-cells rich tumors. Response to induction chemotherapy is better in tumors less infiltrated by macrophages and mostly infiltrated by T cells.

Clinical relevance of tumor infiltrating lymphocytes, PD-L1 expression and correlation with HPV/p16 in head and neck cancer treated with bio- or chemo-radiotherapy

To investigate the prognostic value of tumor infiltrating lymphocytes (TILs: CD8+ and FoxP3+), and PD-L1 expression in patients with head and neck squamous cell carcinoma (HNSCC) treated with radiotherapy combined with cisplatin (CRT) or cetuximab (BRT). Immunohistochemistry for CD8, FoxP3 was performed on pretreatment tissue samples of 77 HNSCC patients. PD-L1 results were evaluable in 38 patients. Cox regression analysis was used to analyze the correlations of these biomarkers expression with clinicopathological characteristics and treatment outcomes. High CD8+ TILs level was identified in multivariate analysis (MVA) as an independent prognostic factor for improved progression-free survival with a non-significant trend for better overall survival (OS). High FoxP3+ TILs and PD-L1+ correlated with a favorable OS in the uni-variate analysis, respectively, but not in the MVA. In subgroup analysis, CD8+TILs appear to play a pivotal role, p16+/high CD8+TILs patients had superior 5-year OS compared with p16+/low CD8+TILs, p16-/ high CD8+TILs, and p16-/ low CD8+TILs patients. p16+/PD-L1+ patients had improved 3-year OS compared with p16+/PD-L1-, p16-/ PD-L1+, and p16-/ PD-L1- patients. In low CD8+ TILs tumors, 5-year loco-regional control of patients treated with CRT was improved vs. those with BRT (p = 0.01) while no significant difference in high CD8+ TILs was observed. CD8+ TILs correlated with an improved clinical outcome in HNSCC patients independent of Human papillomavirus status. The immunobiomarkers may provide information for selecting suitable patients for cisplatin or cetuximab treatment. Additionally, the impact of TILs and PD-L1 of deciphering among the p16+ population a very favorable outcome population could be of interest for patients tailored approaches.

TILs in Head and Neck Cancer: Ready for Clinical Implementation and Why (Not)?

The assessment of tumor infiltrating lymphocytes (TILs) has recently emerged as a prognostic biomarker in several solid tumors. Quantification and subtyping of TILs reflects the immune response in the tumor microenvironment, contributing to either tumoral immune attack or escape and thereby affecting outcome. Despite the growing evidence of its value as prognosticator, TILs analysis has not yet found its way to daily clinical practice. The aim of this review is to evaluate whether the current knowledge on TILs in head and neck cancer justifies its clinical implementation. Therefore, we summarize the data on TILs in squamous cell cancer of the head and neck with focus on the most important subsets (T lymphocytes and more specifically CD8⁺ cytotoxic T cells and FoxP3⁺ regulatory T cells) and site-specific characteristics such as Human Papilloma Virus infection. In addition, we discuss methodological problems and pitfalls that can account for discordant findings and that may hamper inclusion of TILs assessment in routine practice of pathologists and oncologists.

Tumor Eradication by Cisplatin Is Sustained by CD80/86-Mediated Costimulation of CD8+ T Cells

Certain cytotoxic chemotherapeutic drugs are immunogenic, stimulating tumor immunity through mechanisms that are not completely understood. Here we show how the DNA-damaging drug cisplatin modulates tumor immunity. At the maximum tolerated dose (MTD), cisplatin cured 50% of mice with established murine TC-1 or C3 tumors, which are preclinical models of human papillomavirus (HPV)-associated cancer. Notably, the curative benefit of cisplatin relied entirely upon induction of tumor-specific CD8⁺ T cells. Mechanistic investigations showed that cisplatin stimulated tumor infiltration of inflammatory antigen-presenting cells (APC) expressing relatively higher levels of the T-cell costimulatory ligands CD70, CD80, and CD86. Cell death triggered by cisplatin was associated with the release of at least 19 proteins in the tumor environment that could act as damage-associated molecular patterns and upregulate costimulatory molecules, either alone or in concert, but the responsible proteins remain unknown. Essentially, the curative effect of cisplatin was abrogated in mice lacking expression of CD80 and CD86 on APCs. Furthermore, cisplatin treatment was improved by CTLA-4 blockade, which increases the availability of CD80/86 to bind to CD28. In contrast, there was no effect of CD27 stimulation, which replaces CD70 interaction. At the cisplatin MTD, cure rates could also be increased by vaccination with synthetic long peptides, whereas cures could also be achieved at similar rates at 80% of the MTD with reduced side effects. Our findings reveal an essential basis for the immunogenic properties of cisplatin, which are mediated by the induction of costimulatory signals for CD8⁺ T-cell-dependent tumor destruction. Cancer Res; 76(20); 6017-29. ©2016 AACR.

Composition of inflammatory cells regulating the response to concurrent chemoradiation therapy for HPV (+) tonsil cancer

BACKGROUND

Human papillomavirus (HPV) (+) tonsil squamous cell carcinoma (TSCC) responds well to concurrent chemoradiation therapy (CCRT) and demonstrates a favorable prognosis. However, cases of HPV (+) TSCC-related death remain unresolved. We evaluated the distribution and prognostic value of inflammatory cells in HPV (+) TSCC.

METHODS

We reviewed the medical records of 53 patients who were diagnosed with TSCC. HPV (+) TSCC was confirmed using HPV DNA PCR and immunohistochemical p16 overexpression. The numbers of CD4 (+), CD8 (+), and CD68 (+) stained cells were used to evaluate peritumoral lymphocyte infiltration. Patients were divided into two groups according to the mean numbers of stained cells and the mean ratios of each cell type.

RESULTS

HPV (+) was noted in 39 patients. During the follow-up period, 27 patients had no evidence of disease, 2 patients showed disease, and 10 patients died of disease. In this group, advanced T and N stages were not related to overall or disease-specific survival outcomes. The overall survival rate was affected by a high CD68 (+) (HR=19.8; P=0.040) and low CD8/CD4 ratio (HR=7.7, P=0.025). The disease-specific survival rate was affected by a high number of CD68 (+) cells (HR=15.2; P=0.03) and low CD8 (+)/CD4 (+) ratio (HR=3.3; P=0.04).

CONCLUSIONS

The number of CD68 (+) cells and the distribution of cytotoxic or immunosuppressive T lymphocytes could be determining factors for CCRT outcomes in HPV (+) TSCC patients.

Prognostic Value of Homotypic Cell Internalization by Nonprofessional Phagocytic Cancer Cells

BACKGROUND

In this study, we investigated the prognostic role of homotypic tumor cell cannibalism in different cancer types.

METHODS

The phenomenon of one cell being internalized into another, which we refer to as "cell-in-cell event," was assessed in 416 cases from five head and neck cancer cohorts, as well as one anal and one rectal cancer cohort. The samples were processed into tissue microarrays and immunohistochemically stained for E-cadherin and cleaved caspase-3 to visualize cell membranes and apoptotic cell death.

RESULTS

Cell-in-cell events were found in all of the cohorts. The frequency ranged from 0.7 to 17.3 cell-in-cell events per mm(2). Hardly any apoptotic cells were found within the cell-in-cell structures, although apoptotic cell rates were about 1.6 to two times as high as cell-in-cell rates of the same tissue sample. High numbers of cell-in-cell events showed adverse effects on patients' survival in the head and neck and in the rectal cancer cohorts. In multivariate analysis, high frequency was an adverse prognostic factor for overall survival in patients with head and neck cancer (p = 0.008).

CONCLUSION

Cell-in-cell events were found to predict patient outcomes in various types of cancer better than apoptosis and proliferation and might therefore be used to guide treatment strategies.

The effect of ionizing radiation on regulatory T cells in health and disease

Treg cells are key elements of the immune system which are responsible for the immune suppressive phenotype of cancer patients. Interaction of Treg cells with conventional anticancer therapies might fundamentally influence cancer therapy response rates. Radiotherapy, apart from its direct tumor cell killing potential, has a contradictory effect on the antitumor immune response: it augments certain immune parameters, while it depresses others. Treg cells are intrinsically radioresistant due to reduced apoptosis and increased proliferation, which leads to their systemic and/or intratumoral enrichment. While physiologically Treg suppression is not enhanced by irradiation, this is not the case in a tumorous environment, where Tregs acquire a highly suppressive phenotype, which is further increased by radiotherapy. This is the reason why the interest for combined radiotherapy and immunotherapy approaches focusing on the abrogation of Treg suppression has increased in cancer therapy in the last few years. Here we summarize the basic mechanisms of Treg radiation response both in healthy and cancerous environments and discuss Treg-targeted pre-clinical and clinical immunotherapy approaches used in combination with radiotherapy. Finally, the discrepant findings regarding the predictive value of Tregs in therapy response are also reviewed.

Immunomodulatory effects of peplomycin on immunosuppressive and cytotoxic cells in the lesional skin of cutaneous squamous cell carcinoma

BACKGROUND

Continuous intra-arterial administration of peplomycin (PEP) through a tumor-feeding artery using an intravascular indwelling catheter is one of the best treatments for cutaneous squamous cell carcinoma (SCC) on cosmetic areas. Although this reagent is useful for the treatment of SCC, its immunomodulatory effect on the tumor microenvironment is still unknown.

OBJECTIVE/METHODS

In this study, we investigated the immunomodulatory effects of PEP on the tumor-infiltrating regulatory T cells and tumor-associated macrophages as well as CD8(+)TIA-1(+) cytotoxic T cells in the lesional skin of 5 patients with SCC on the lips.

RESULTS

Our data suggest that, in addition to the direct antitumor effects, PEP decreased immunosuppressive cells and increased cytotoxic T lymphocytes at the tumor sites, which might maintain antitumor immune response against SCC.

Developmental regulation of p53-dependent radiation-induced thymocyte apoptosis in mice

The production of T cell receptor αβ(+) (TCRαβ(+) ) T lymphocytes in the thymus is a tightly regulated process that can be monitored by the regulated expression of several surface molecules, including CD4, CD8, cKit, CD25 and the TCR itself, after TCR genes have been assembled from discrete V, D (for TCR-β) and J gene segments by a site-directed genetic recombination. Thymocyte differentiation is the result of a delicate balance between cell death and survival: developing thymocytes die unless they receive a positive signal to proceed to the next stage. This equilibrium is altered in response to various physiological or physical stresses such as ionizing radiation, which induces a massive p53-dependent apoptosis of CD4(+) CD8(+) double-positive (DP) thymocytes. Interestingly, these cells are actively rearranging their TCR-α chain genes. To unravel an eventual link between V(D)J recombination activity and thymocyte radio-sensitivity, we analysed the dynamics of thymocyte apoptosis and regeneration following exposure of wild-type and p53-deficient mice to different doses of γ-radiation. p53-dependent radio-sensitivity was already found to be high in immature CD4(-) CD8(-) (double-negative, DN) cKit(+) CD25(+) thymocytes, where TCR-β gene rearrangement is initiated. However, TCR-αβ(-) CD8(+) immature single-positive thymocytes, an actively cycling intermediate population between the DN and DP stages, are the most radio-sensitive cells in the thymus, even though their apoptosis is only partially p53-dependent. Within the DP population, TCR-αβ(+) thymocytes that completed TCR-α gene recombination are more radio-resistant than their TCR-αβ(-) progenitors. Finally, we found no correlation between p53 activation and thymocyte sensitivity to radiation-induced apoptosis.

Radiochemotherapy fosters a favorable pattern of inflammatory cells in head and neck tumors

The immune milieu in malignant tumors can influence the prognosis of patients. However, little is known about the effect the antitumoral therapy has on the inflammatory infiltrate. In head and neck squamous cell carcinoma we found evidence that a neoadjuvant radiochemotherapy could modulate the composition of the intratumoral inflammation into an anti-tumoral pattern.

Chemoradiotherapy-induced upregulation of PD-1 antagonizes immunity to HPV-related oropharyngeal cancer

While viral antigens in human papillomavirus (HPV)-related oropharyngeal cancer (HPVOPC) are attractive targets for immunotherapy, the effects of existing standard-of-care therapies on immune responses to HPV are poorly understood. We serially sampled blood from patients with stage III-IV oropharyngeal cancer undergoing concomitant chemoradiotherapy with or without induction chemotherapy. Circulating immunocytes including CD4(+) and CD8(+) T cells, regulatory T cells (Treg), and myeloid-derived suppressor cells (MDSC) were profiled by flow cytometry. Antigen-specific T-cell responses were measured in response to HPV16 E6 and E7 peptide pools. The role of PD-1 signaling in treatment-related immunosuppression was functionally defined by performing HPV-specific T-cell assays in the presence of blocking antibody. While HPV-specific T-cell responses were present in 13 of 18 patients before treatment, 10 of 13 patients lost these responses within 3 months after chemoradiotherapy. Chemoradiotherapy decreased circulating T cells and markedly elevated MDSCs. PD-1 expression on CD4(+) T cells increased by nearly 2.5-fold after chemoradiotherapy, and ex vivo culture with PD-1-blocking antibody enhanced HPV-specific T-cell responses in 8 of 18 samples tested. Chemoradiotherapy suppresses circulating immune responses in patients with HPVOPC by unfavorably altering effector:suppressor immunocyte ratios and upregulating PD-1 expression on CD4(+) T cells. These data strongly support testing of PD-1-blocking agents in combination with standard-of-care chemoradiotherapy for HPVOPC.

In vivo effects of lattice radiation therapy on local and distant lung cancer: potential role of immunomodulation

Radiation is a potent immune-modulator that elicits cell death upon tumor, stromal and angiogenic compartments of tumor microenvironment. Here, we test a novel approach of high-dose radiation delivery using three dimensional volume based lattice radiation therapy (LRT) to understand the impact of different volume irradiation in eliciting both local and metastatic/distant tumor control through modulation of tumor immune micro-environment. To study such effects of LRT, tumors were implanted in both hind legs of C57BL/6 mice using Lewis lung carcinoma 1 (LLC1) cells. Mice were divided into five groups: untreated; partial tumor volume groups included two 10% vertices, one 20% vertex and one 50% vertex of the total tumor volume; and 100% open-field irradiation. Tumors implanted in the left flank were irradiated with a single dose of 20 Gy while the tumors in the right flank were unirradiated. Tumor growth and regression as well as immune responses (such as Th1 and Th2; T-cell infiltration) were determined after radiation treatment. Results demonstrated that both 100% open-field irradiation and 20% volume irradiation (in two 10% volumes) resulted in significant growth delay in the irradiated tumor. Further, all types of radiation exposures, partial or 100% volume, demonstrated distal effectiveness, however, 20% volume irradiation (in two 10% volumes) and 50% tumor volume irradiation led to maximum growth delay. Mice treated with partial tumor volume radiation induced a robust IFN-γ and Th1 response when compared to whole-tumor irradiation and down-modulated Th2 functions. The presence of increased CD3+ cells and TRAIL in partially irradiated tumor volumes correlated well with tumor growth delay. Further, serum obtained from any of the LRT treated mice caused growth inhibition of endothelial cells when compared to serum obtained from either untreated or open-field irradiated groups. These results indicate that high-dose partial volume irradiation can cause an improved distant effect than the total tumor volume irradiation through activating the host immune system.

CD8+ and FOXP3+ tumor-infiltrating T cells before and after chemoradiotherapy for rectal cancer

BACKGROUND

CD8+ cytotoxic T cells and forkhead box P3 (FOXP3)+ regulatory T cells are major players in tumor immunity. Increased CD8+ tumor-infiltrating lymphocytes (TILs) and high CD8/FOXP3 TIL ratios are associated with improved survival. Neoadjuvant chemoradiotherapy (CRT) can result in tumor regression; however, immunomodulation during CRT for rectal cancer has not been thoroughly assessed. We investigated whether neoadjuvant CRT altered the in situ immune cell population and clinical implications of TIL accumulation before and after CRT.

METHODS

We recruited 93 rectal cancer patients who underwent neoadjuvant CRT and radical resection. Pretreatment biopsy and post-CRT resected specimens were immunostained for CD8 and FOXP3, and the densities of stromal (STL) and intraepithelial (IEL) immunopositive TILs were determined separately. In addition, 54 patients with resections but without neoadjuvant CRT were enrolled for comparison.

RESULTS

CD8+ STL density doubled after CRT (average counts: 92 vs. 230 per microscopic field using a 20 × objective lens; P < 0.0001), whereas FOXP3+ STL counts remained stable (109 vs. 109). Compared with non-CRT cases, CRT increased CD8+ STL density. Multivariate analyses demonstrated that high post-CRT CD8 + STL density was associated with better prognosis (5-year recurrence-free survival: 87.5 vs. 57.8 %; P = 0.0058) and that a high pretreatment CD8/FOXP3 IEL ratio was a predictor of favorable tumor regression (P = 0.0029).

CONCLUSIONS

Favorable anticancer immunity occurred after CRT for rectal cancer by altering TIL subsets. A high CD8/FOXP3 IEL ratio before CRT and a high CD8+ STL density after CRT were associated with a favorable clinical outcome.

Somatic evolution of head and neck cancer - biological robustness and latent vulnerability

Despite recent advancements in multidisciplinary treatments, the overall survival and quality of life of patients with advanced head and neck squamous cell carcinoma (HNSCC) have not improved significantly over the past decade. Molecular targeted therapies, which have been addressed and advanced by the concept of “oncogene addiction”, have demonstrated only limited successes so far. To explore a novel clue for clinically effective targeted therapies, we analyzed the molecular circuitry of HNSCC through the lens that HNSCC is an evolving system. In the trajectory of this somatic evolution, HNSCC acquires biological robustness under a variety of selective pressures including genetic, epigenetic, micro‐environmental and metabolic stressors, which well explains the major mechanism of “escaping from oncogene addiction”. On the other hand, this systemic view appears to instruct us approaches to target latent vulnerability of HNSCC that is masked behind the plasticity and evolvability of this complex adaptive system.

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There is an urgent need to develop a novel conceptual framework for the treatment of HNSCC.

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The biological robustness of HNSCC was analyzed through a somatic evolution model.

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This model well explains the mechanism of “escaping from oncogene addiction”.

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We discuss about the possible approaches to target vulnerability of evolving HNSCC.

Complete clinical responses to cancer therapy caused by multiple divergent approaches: a repeating theme lost in translation

Over 50 years of cancer therapy history reveals complete clinical responses (CRs) from remarkably divergent forms of therapies (eg, chemotherapy, radiotherapy, surgery, vaccines, autologous cell transfers, cytokines, monoclonal antibodies) for advanced solid malignancies occur with an approximately similar frequency of 5%–10%. This has remained frustratingly almost static. However, CRs usually underpin strong durable 5-year patient survival. How can this apparent paradox be explained? Over some 20 years, realization that (1) chronic inflammation is intricately associated with cancer, and (2) the immune system is delicately balanced between responsiveness and tolerance of cancer, provides a greatly significant insight into ways cancer might be more effectively treated. In this review, divergent aspects from the largely segmented literature and recent conferences are drawn together to provide observations revealing some emerging reasoning, in terms of “final common pathways” of cancer cell damage, immune stimulation, and auto-vaccination events, ultimately leading to cancer cell destruction. Created from this is a unifying overarching concept to explain why multiple approaches to cancer therapy can provide complete responses at almost equivalent rates. This “missing” aspect provides a reasoned explanation for what has, and is being, increasingly reported in the mainstream literature – that inflammatory and immune responses appear intricately associated with, if not causative of, complete responses induced by divergent forms of cancer therapy. Curiously, whether by chemotherapy, radiation, surgery, or other means, therapy-induced cell injury results, leaving inflammation and immune system stimulation as a final common denominator across all of these mechanisms of cancer therapy. This aspect has been somewhat obscured and has been “lost in translation” to date.