Influence of neoadjuvant radio-chemotherapy on tumor-infiltrating lymphocytes in squamous esophageal cancer

Definitive chemoradiotherapy induces T-cell-inflamed tumor microenvironment in unresectable locally advanced esophageal squamous cell carcinoma

BACKGROUND

Chemoradiotherapy (CRT) modulates the tumor immune microenvironment of multiple cancer types, including esophageal cancer, which potentially induces both immunogenicity and immunosuppression by upregulating the presentation of tumor-specific antigens and immune checkpoint molecules in tumors, respectively. The prognostic effects of immune modification by CRT in esophageal squamous cell carcinoma (ESCC) remain controversial because of the lack of detailed immunological analyses using paired clinical specimens before and after CRT. We aimed to clarify the immunological changes in the tumor microenvironment caused by CRT and elucidate the predictive importance of clinical response and prognosis and the rationale for the necessity of subsequent programmed cell death protein 1 (PD-1) inhibitor treatment.

METHODS

In this study, we performed a comprehensive immunological analysis of paired biopsy specimens using multiplex immunohistochemistry before and after CRT in patients with unresectable locally advanced ESCC.

RESULTS

CRT significantly increased the intra-tumoral infiltration and PD-1 expression of CD8+ T cells and conventional CD4+ T cells but decreased those of regulatory T cells and the accumulation of tumor-associated macrophages. Multivariate analysis of tumor-infiltrating T-cell phenotypes revealed that the density of PD-1+CD8+ T cells in the tumor after CRT could predict a confirmed complete response and favorable survival.

CONCLUSIONS

This study showed that CRT improved the immunological characteristics of unresectable locally advanced ESCC and identified the density of PD-1+CD8+ T cells as a predictive factor for prognosis. This finding supports the rationale for the necessity of subsequent PD-1 inhibitor treatment.

Immunotherapy for Esophageal Cancer: State-of-the Art in 2021

The management of esophageal cancer (EC) has experienced manifold changes during the last decades. Centralization of EC treatment has been introduced in many countries, subsequently allowing the development of specialized high-volume centers. Minimal invasive surgery has replaced open surgery in many centers, whereas more potent systemic treatments have been introduced in clinical practice. Newer chemotherapy regimens increase long-term survival. Nevertheless, the overall survival of EC patients remains dismal for advanced tumor stages. In this direction, a wide range of targeted biologic agents (immunotherapy) is currently under assessment. Anti- Human Epidermal Growth Factor Receptor-2 (HER-2) monoclonal antibodies are used in HER2 (+) tumors, predominantly well-differentiated adenocarcinomas, and are currently assessed in the neoadjuvant setting (TRAP, INNOVATION trials). Immune checkpoint inhibitors Nivolumab (ATTRACTION-03) and pembrolizumab (KEYNOTE-181), have demonstrated a survival benefit compared with conventional chemotherapy in heavily pre-treated progressive disease. More recently, CheckMate-577 showed very promising results for nivolumab in a curative adjuvant setting, improving disease-free survival mainly for esophageal squamous cell carcinoma. Several ongoing trials are investigating novel targeted agents in the preoperative setting of locally advanced EC. In addition, other immunomodulatory approaches such as peptide vaccines and tumor infiltrating lymphocytes (TILs) are currently under development and should be increasingly integrated into clinical practice.

Tumor-immune landscape patterns before and after chemoradiation in resectable esophageal adenocarcinomas

Immunotherapy is a new anti‐cancer treatment option, showing promising results in clinical trials. To investigate potential immune biomarkers in esophageal adenocarcinoma (EAC), we explored immune landscape patterns in the tumor microenvironment before and after neoadjuvant chemoradiation (nCRT). Sections from matched pretreatment biopsies and post‐nCRT resection specimens (n = 188) were stained for (1) programmed death‐ligand 1 (PD‐L1, CD274); (2) programmed cell death protein 1 (PD‐1, CD279), forkhead box P3 (FOXP3), CD8, pan‐cytokeratin multiplex; and (3) an MHC class I, II duplex. The densities of tumor‐associated immune cells (TAICs) were calculated using digital image analyses and correlated to histopathological nCRT response [tumor regression grade (TRG)], survival, and post‐nCRT immune patterns. PD‐L1 positivity defined by a combined positive score of >1 was associated with a better response post‐nCRT (TRG 1–3 versus 4, 5, p = 0.010). In addition, high combined mean densities of CD8⁺, FOXP3⁺, and PD‐1⁺ TAICs in the tumor epithelium and stroma of biopsies were associated with a better response (TRG 1–3 versus 4, 5, p = 0.025 and p = 0.044, respectively). Heterogeneous TAIC density patterns were observed post‐nCRT, with significantly higher CD8⁺ and PD‐1⁺ TAIC mean densities compared with biopsies (both p = 0.000). Three immune landscape patterns were defined post‐nCRT: ‘inflamed’, ‘invasive margin’, and ‘desert’, of which ‘inflamed’ was the most frequent (57%). Compared with matched biopsies, resection specimens with ‘inflamed’ tumors showed a significantly higher increase in CD8⁺ density compared with non‐inflamed tumors post‐nCRT (p = 0.000). In this cohort of EAC patients, higher TAIC densities in pretreatment biopsies were associated with response to nCRT. This warrants future research into the potential of the tumor‐immune landscape for patient stratification and novel (immune) therapeutic strategies. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd on behalf of The Pathological Society of Great Britain and Ireland.

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.

Immune Checkpoint Inhibitors in Esophageal Cancers: are we Finally Finding the Right Path in the Mist?

Esophageal cancer remains a challenging disease due to limited treatment options and poor prognosis. In recent years, immune checkpoint inhibitors (ICI) have been proven to be safe and effective in the treatment of highly lethal malignancies, such as non-small cell lung cancer and melanoma. Recent clinical trials also showed promising activity in immune checkpoint inhibitors in pretreated advanced esophageal carcinoma and a potentially significant impact on the outcome of selected patients, independently of histology. Combination studies evaluating immunotherapy and chemotherapy and, in localized disease, radiotherapy are in progress and will hopefully confirm their promises in the near future. However, reliable predictive biomarkers are still lacking. Indeed, at present, the role of programmed cell death ligand 1 expression and other factors (such as microsatellite instability and tumor mutational burden) as predictive biomarkers of benefit to immune checkpoint inhibitors is still controversial. Our aim was to explore the rationale of ICIs in esophageal cancer, review the results already available in multiple settings, and investigate future perspectives with single-agent and combination strategies.

Tumor Infiltrating Lymphocytes and CD8+ T Cell Subsets as Prognostic Markers in Patients with Surgically Treated Laryngeal Squamous Cell Carcinoma

To evaluate the prognostic significance of tumor infiltrating lymphocytes (TILs) and of CD8+ T-cell subsets in patients with surgically treated laryngeal squamous cell carcinoma (LSCC), LSCC from 283 patients were examined. TIL density was morphologically assessed on whole sections. CD8+ cell counts/mm² were evaluated on multiple tissue microarray cores per tumor (median counts for high/low CD8+/mm²). TIL density and CD8+ counts weakly correlated with each other (Spearman's rho = 0.348). Heterogeneous CD8+ counts/mm² were demonstrated in 28% of the tumors. In univariate analysis, a significant interaction was observed between CD8 expression and nodal status with respect to outcome; in node-positive patients, those with high CD8+ tumors had 77% lower risk of relapse (interaction p < 0.001) and 74% lower risk for death (interaction p = 0.002) compared to patients with low CD8+ tumors. In multivariate analysis, higher TIL density independently conferred lower risk for relapse in the entire cohort (HR 0.87; 95% CI 0.77-0.98; Wald's p = 0.017) and in node-positive patients (HR 0.41; 95% CI 0.23-0.75; p = 0.003) and, similarly, for death (p = 0.025 and p = 0.003, respectively). High CD8+ was not a significant independent prognostic marker in any analysis setting. The assessment of CD8+ infiltrates does not seem to offer additional prognostic information over the morphologically assessed TIL density. It also appears that the favorable prognostic impact of higher TIL density and CD8+ infiltrates mostly concerns node-positive but not node-negative disease. If validated in larger node-positive cohorts, these findings are worth considering for the diagnostic development of immune cell infiltrates in LSCC.

Cytotoxic T lymphocyte antigen-4 expression in esophageal carcinoma: implications for prognosis

To examine the relationship between cytotoxic T lymphocyte antigen-4 (CTLA-4) expression and esophageal carcinoma prognosis, CTLA-4 expression was immunohistochemically detected in paraffin-embedded primary tumor specimens from 158 patients with esophageal cancer. CTLA-4 was detected in the cytoplasm and cell membranes of esophageal cancer cells and in interstitial lymphocytes. In univariate analyses (log-rank), higher interstitial CTLA-4⁺ lymphocyte density and higher tumor CTLA-4 expression were associated with shorter overall survival (OS). After controlling for age and clinical stage, multivariate analysis (Cox) found that tumor CTLA-4 expression was an independent predictor of shorter OS (HR 2.016, P = 0.004). These results indicate that CTLA-4 expression in the tumor environment (both lymphocytes and tumor cells) is associated with poorer prognosis. In addition, CTLA-4 profiles may be useful for predicting the benefits and toxicity of CTLA-4 blockade in patients with esophageal carcinoma.

Prognostic significance of IgG4+ plasma cell infiltrates following neoadjuvant chemoradiation therapy for esophageal adenocarcinoma

Lymphoplasmacytic infiltrates in esophageal adenocarcinoma (EAC) tissue following chemoradiotherapy (CRT) reflect alterations in the tumor immunoenvironment. The presence and role of plasma cells in this process are poorly understood. Our aim was to characterize the IgG4+ plasma cell population in EAC following CRT. Seventy-one esophagectomy specimens post-CRT were compared with a surgery-only group of 31 EACs. The distribution, density, and ratio of IgG4+ and IgG+ plasma cells were evaluated by immunohistochemistry and correlated with clinicopathologic features, treatment response, and survival. In the CRT group, the presence of higher numbers of IgG4+ (≥ median of 94/high-power field) and IgG+ (≥ median of 225/high-power field) plasma cells and increased IgG4+/IgG+ ratio (≥ median of 41%) within ulcers was associated with complete or near-complete treatment response (P = .0077, P = .0503, and P = .0063, respectively). Lower tumor grade, smaller tumor size, and higher levels of IgG4+ plasma cells in posttherapy ulcers significantly correlated with better overall survival, whereas pretherapy clinical stage, posttherapy pathologic stage, smaller tumor size, and lower tumor grade were associated with longer recurrence-free survival. Multivariate analysis revealed that both posttherapy pathologic stage and high IgG4+ plasma cells in ulcers were independent predictors of overall survival (P = .05 and P = .01), whereas only posttherapy pathologic stage was associated with recurrence-free survival (P < .01). This is the first study describing a dense IgG4+ plasma cell infiltrate in EAC following CRT. The presence of increased IgG4+ plasma cells may be a novel reliable factor to predict prognosis of EAC patients following CRT.

Are tumor-infiltrating lymphocytes protagonists or background actors in patient selection for cancer immunotherapy?

INTRODUCTION

Tumor-infiltrating lymphocytes (TILs) are frequently observed in several tumors, reflecting the dynamic process of '"cancer immunoediting"'. Prognostic and predictive values of TILs have been demonstrated in different cancers, proving their pivotal role in clinical outcome. In recent years, new therapies targeting immune checkpoint inhibitors, especially CTLA-4 and PD-1/PDL-1 pathways, have been introduced into clinical practice. In this context, TILs may even have a possible utility as a predictive biomarker for immunotherapy response. Areas covered: In this review, the authors summarize the most relevant knowledge related to TILs. This includes their prognostic and predictive significance in various types of tumour and the recent findings about their potential role in the cancer immunotherapy. Expert opinion: TILs evaluation could lead to a predictive biomarker for immunotherapy effectiveness in several cancer types. Furthermore, typing of TILs subpopulation could have clinical relevance in patient selection for treatment with immune checkpoint inhibitors. However further studies are still needed.

SIX1 overexpression predicts poor prognosis and induces radioresistance through AKT signaling in esophageal squamous cell carcinoma

The Sineoculis homeobox homolog 1 (SIX1) protein has been found to be overexpressed in several human cancers. However, its expression pattern and biological roles in esophageal squamous cell carcinoma (ESCC) remain unexplored. This study examined the clinical significance of SIX1 in 119 ESCC tissues. It was found that SIX1 protein was upregulated in 36.9% (44/119) cases. SIX1 overexpression was an independent predictor for short survival of ESCC patients. siRNA knockdown and plasmid transfection were carried out in ESCC cell lines. SIX1 depletion inhibited cell growth, invasion, and colony formation, whereas its overexpression facilitated in vivo and in vitro cell growth, invasion, and colony formation. The apoptosis rate induced by X-ray irradiation was substantially increased by SIX1 knockdown in Eca-109 cells. Ectopic overexpression of SIX1 in TE-1 cells dramatically enhanced resistance to irradiation. Western blot analysis showed that SIX1 depletion downregulated cyclin E, matrix metalloproteinase-2 (MMP-2), Bcl-2 expression and upregulated Bim expression. SIX1 overexpression exhibited the opposite effect on these proteins. In addition, it was found that SIX1 could positively regulate extracellular signal-regulated kinase (ERK) and AKT signaling pathway. ERK inhibitor abolished the effect of SIX1 on MMP-2 expression. AKT inhibitor treatment blocked the role of SIX1 on anti-apoptotic protein Bcl-2. In conclusion, this study demonstrates that SIX1 overexpression predicts poor survival in ESCC patients and confers radioresistance through activation of AKT signaling pathways.

Association between Chemotherapy-Response Assays and Subsets of Tumor-Infiltrating Lymphocytes in Gastric Cancer: A Pilot Study

Purpose

The purpose of this pilot study was to evaluate the association between adenosine triphosphate-based chemotherapy response assays (ATP-CRAs) and subsets of tumor infiltrating lymphocytes (TILs) in gastric cancer.

Materials and Methods

In total, 15 gastric cancer tissue samples were obtained from gastrectomies performed between February 2007 and January 2011. Chemotherapy response assays were performed on tumor cells from these samples using 11 chemotherapeutic agents, including etoposide, doxorubicin, epirubicin, mitomycin, 5-fluorouracil (5-FU), oxaliplatin, irinotecan, docetaxel, paclitaxel, methotrexate, and cisplatin. TILs in the tissue samples were evaluated using antibodies specific for CD3, CD4, CD8, Foxp3, and Granzyme B.

Results

The highest cancer cell death rates were induced by etoposide (44.8%), 5-FU (43.1%), and mitomycin (39.9%). Samples from 10 patients who were treated with 5-FU were divided into 5-FU-sensitive and -insensitive groups according to median cell death rate. No difference was observed in survival between the two groups (P=0.216). Only two patients were treated with a chemotherapeutic agent determined by an ATP-CRA and there was no significant difference in overall survival compared with that of patients treated with their physician's choice of chemotherapeutic agent (P=0.105). However, a high number of CD3 TILs was a favorable prognostic factor (P=0.008). Pearson's correlation analyses showed no association between cancer cell death rates in response to chemotherapeutic agents and subsets of TILs.

Conclusions

Cancer cell death rates in response to specific chemotherapeutic agents were not significantly associated with the distribution of TIL subsets.

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.

Immunological impact of neoadjuvant chemoradiotherapy in patients with borderline resectable pancreatic ductal adenocarcinoma

BACKGROUND

Little is known about the immunological effect of neoadjuvant chemoradiotherapy (NACRT) in the tumor microenvironment of pancreatic ductal adenocarcinoma. The objective of this study was to examine the immunological modifications induced by NACRT in patients with pancreatic cancer.

METHODS

Fifty-two patients with pancreatic cancer who underwent surgical resection were enrolled in this study. NACRT was administered to 22 patients, whereas the other 30 patients underwent surgical resection without NACRT. The resected tumor specimens were analyzed for the presence of tumor-infiltrating lymphocytes by using immunohistochemical staining for CD4, CD8, CD68, CD163, Foxp3, and major histocompatibility complex class I (MHC class I) antigen.

RESULTS

The number of CD4+ and CD8+ lymphocytes was significantly higher in patients who received NACRT than in those who did not receive NACRT. No significant difference in MHC class I expression was observed between the groups. In the NACRT group, patients with a high accumulation of CD8+ cells experienced longer overall survival than those with a low number of CD8+ cells.

CONCLUSIONS

NACRT may induce the accumulation of CD4+ and CD8+ cells in the tumor microenvironment and a high accumulation of CD8+ cells might be a good prognostic marker for pancreatic cancer treated with NACRT.

Prognostic importance of tumour-infiltrating memory T cells in oesophageal squamous cell carcinoma

Memory T cells survive for many months and years and are critically important for host defence in humans. In tumour immunity, they have been also suggested to play a significant role in tumour progression and metastasis. However, the role of memory T cells in actual human cancer remains largely unknown. In this study, the clinical importance of tumour-infiltrating CD45RO(+) memory T cells was investigated in human oesophageal squamous cell carcinoma (OSCC). CD45RO(+) T cells were evaluated by immunohistochemistry in primary OSCC tumours from 105 patients. Patients were classified into two groups as CD45RO(+hi) or CD45RO(+lo) based on the number of cells stained positively for CD45RO. No significant difference was observed between CD45RO status and several clinicopathological prognostic factors. However, the postoperative overall and disease-free survival for CD45RO(+hi) patients was significantly better than for CD45RO(+lo) patients. Furthermore, there were significant correlations of CD45RO status in the primary tumour with postoperative lymph node and pulmonary recurrence, suggesting that memory T cells may control postoperative metastatic recurrence. Most importantly, CD45RO(+) memory T cell status has a significant prognostic value for OSCC independently of conventional tumour-node-metastasis (TNM) classification. Our study may provide a rationale for developing a novel immunotherapy in intentional induction of memory T cells for the treatment of oesophageal cancer.

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

Head and neck squamous cell cancers (HNSSC) generate an immune-suppressive micro-environment by a specific pattern of tumour infiltrating inflammatory cells. The aim of our study was to evaluate the impact of radiochemotherapy on the numbers and composition of inflammatory cells and its influence on outcome. Fifty-eight patients suffering from oral cavity cancer were studied, whose therapy consisted of concurrent radiochemotherapy followed by surgery. Numbers and ratios of tumour infiltrating inflammatory cells were compared prior to and after radiochemotherapy. Intraepithelial and stromal location of tumour infiltrating inflammatory cells was analysed separately. Infiltration of CD3(+), CD4(+), CD25(+), FoxP3(+), CD8(+), Granzyme B(+), CD20(+) and CD68(+) cells predominated in the peritumoural stromal compartment, whereas CD1a(+) dendritic cells were found more frequently in the intraepithelial compartment. Neoadjuvant treatment was associated with a general decrease of tumour infiltrating inflammatory cells in both compartments. The CD8(+) and Granzyme B(+) cytotoxic cells decreased only slightly after RCT. In contrast, the decrease of FoxP3(+) regulatory T cells was more pronounced and the cytotoxic T-cell/FoxP3(+) ratio increased 2- to 3-fold in both compartments, respectively. Patients with high cytotoxic cell numbers, high dendritic cell numbers and a high ratio of cytotoxic cells to regulatory T cells had a better disease free survival. Concurrent radiochemotherapy of oral squamous cell carcinoma was shown to drive the composition of inflammatory cells in a direction which is supposed to be prognostically favourable.

Regulatory T cells in gastrointestinal tumors

Regulatory T cells (Tregs) have the ability to suppress the activity of most other lymphoid cells, as well as dendritic cells through cell-cell contact-dependent mechanisms, which have not yet been fully defined. Tregs are a key component of a functional immune system and Treg deficiency is associated with severe autoimmunity and allergies. However, Tregs specific for tumor-associated antigens are present in cancer patients and Tregs accumulate in many types of solid tumors, where they probably act to promote tumor escape from cytotoxic immune responses. Indeed, some studies even show a negative correlation between Treg infiltration and survival of the patient. Several studies indicate an active recruitment of Tregs to the tumor site and the mechanisms of Treg accumulation are starting to be better understood as a result of more detailed analysis of their adhesion molecule and chemokine receptor expression. In addition, in gastrointestinal tumors there is an increase in tumor-associated Tregs, but intriguingly, Treg infiltration into colorectal adenocarcinomas is associated with improved prognosis. In this article, we will review the proposed mechanisms of immune suppression by tumor-associated Tregs, how the tumor microenvironment favors immune evasion and Treg induction, the tumor-homing mechanisms of Tregs and how Tregs affect progression of gastric and colorectal tumors.

Direct effects of chemoradiotherapy following esophagectomy

BACKGROUND

Esophageal cancer is a major cause of morbidity and mortality, but despite continuing research, few effective therapies have been identified. In recent years, surgical resection following chemoradiotherapy has been associated with improved survival in several clinical models.

AIM

In a prospective, observational study, we evaluated the direct effects of chemoradiotherapy on postoperative mortality, morbidity, and inflammatory response in patients following esophagectomy.

METHODS

The study cohort was divided into two groups: the first group received preoperative chemoradiotherapy, while the second group had surgical intervention without prior treatment. Nutritional status was evaluated for the members of both patient groups at various time points.

RESULTS

Preoperative chemoradiotherapy did not influence morbidity or organ function, and the postoperative inflammatory response did not show immunosuppressive side effects directly after surgery.

CONCLUSION

Preoperative chemoradiotherapy does not improve postoperative organ function, inflammatory response or nutritional status in the patients. These findings may help to improve outcome in patients with esophageal cancer in the future.

FOXP3 and RORγt: transcriptional regulation of Treg and Th17

FOXP3(+)CD4(+)CD25(+) Regulatory T (Treg) cells and IL-17 producing helper T cells (Th17) are critical subsets of T cells which play essential roles in immune homeostasis. The Forkhead family transcription factor FOXP3 is predominantly expressed in Treg cells, where the FOXP3 ensemble is essential for Treg cell development and function. As FOXP3 is to Treg cells, the orphan retinoic acid nuclear receptor (ROR) family transcription factor RORγt is essential for Th17 development and function. In this review, we summarize recent progress of our understanding towards the molecular mechanisms underlying the differentiation and function of FOXP3(+) Treg cells and RORγt expressing Th17 cells. These may provide new insights into therapeutic intervention and targeting of human immune-deficient diseases.