SOX17 enables immune evasion of early colorectal adenomas and cancers.

A hallmark of cancer is the avoidance of immune destruction. This process has been primarily investigated in locally advanced or metastatic cancer1-3; however, much less is known about how pre-malignant or early invasive tumours evade immune detection. Here, to understand this process in early colorectal cancers (CRCs), we investigated how naive colon cancer organoids that were engineered in vitro to harbour Apc-null, KrasG12D and Trp53-null (AKP) mutations adapted to the in vivo native colonic environment. Comprehensive transcriptomic and chromatin analyses revealed that the endoderm-specifying transcription factor SOX17 became strongly upregulated in vivo. Notably, whereas SOX17 loss did not affect AKP organoid propagation in vitro, its loss markedly reduced the ability of AKP tumours to persist in vivo. The small fraction of SOX17-null tumours that grew displayed notable interferon-γ (IFNγ)-producing effector-like CD8+ T cell infiltrates in contrast to the immune-suppressive microenvironment in wild-type counterparts. Mechanistically, in both endogenous Apc-null pre-malignant adenomas and transplanted organoid-derived AKP CRCs, SOX17 suppresses the ability of tumour cells to sense and respond to IFNγ, preventing anti-tumour T cell responses. Finally, SOX17 engages a fetal intestinal programme that drives differentiation away from LGR5+ tumour cells to produce immune-evasive LGR5- tumour cells with lower expression of major histocompatibility complex class I (MHC-I). We propose that SOX17 is a transcription factor that is engaged during the early steps of colon cancer to orchestrate an immune-evasive programme that permits CRC initiation and progression.

Investigation of miRNA dysregulation and association with immune cell profile during malignant transformation of colorectal cells.

BACKGROUND: Colorectal cancer (CRC) is one of the most prevalent and life-threatening cancer among the world. Accumulated somatic mutations during malignant transformation process endow cancer cells with increased growth, invasiveness and immunogenicity. These highly immunogenic cancer cells develop multiple strategies to evade immune attack. Through post-transcriptional regulation, microRNAs (miRNAs) not only participate in cancer development and progression but also manipulate anti-cancer immune response. This study aims to identify miRNAs associated with the colorectal cell malignant transformation process and their association with immune cell population using synchronous adjacent normal, polyp and CRC specimens. METHODS: We conducted a Low Density Array to compare the miRNA expression profile of synchronous colorectal adenoma, adenocarcinoma and adjacent normal colon mucosa collected from 8 patients, in order to identify candidate miRNAs involved in CRC progression. These findings were further validated in 14 additional patients and GEO dataset GSE41655. The relative abundance of dendritic cells, natural killer cells, neutrophil and macrophage was determined and correlated with dysregulated miRNA levels. RESULTS: MicroRNA microarray identified 39 miRNAs aberrantly expressed during the colorectal cell transformation process. Seven novel miRNAs were shortlisted, and dysregulation of miR-149-3p, miR-192-3p, miR-335-5p and miR-425 were further validated by the qPCR validation experiment and data retrieved from the GEO dataset. Furthermore, these miRNAs demonstrated certain associations with level of dendritic cells, natural killer cells, neutrophil and macrophage within the polyp or CRC specimens. CONCLUSION: This study revealed miRNA dysregulated during stepwise malignant transformation of colorectal mucosal cells and their association with immune cell population.

Tumor-Associated Macrophages: New Horizons for Pituitary Adenoma Researches.

Macrophages are one of the most common infiltrating immune cells and an essential component of tumor microenvironment. Macrophages and the soluble cytokines and chemokines produced play an important role in tumorigenesis, progression, invasion and metastasis in solid tumors. Despite the multiple studies in other solid tumors, there is little known about macrophages in pituitary adenomas. Recently, studies about pituitary adenoma-infiltrated macrophages have been emerging, including the immunohistochemical and immunophenotypic analysis of the pituitary adenomas and further studies into the mechanism of the crosstalk between macrophages and tumor cells in vivo and in vitro. These studies have offered us new insights into the polarization of macrophages and its role in tumorigenesis, progression and invasion of pituitary adenomas. This review describes the advances in the field of pituitary adenoma-infiltrated macrophages and the prospect of targeting macrophages as cancer therapy in pituitary adenoma.

The Upregulation of Molecules Related to Tumor Immune Escape in Human Pituitary Adenomas.

Human pituitary adenomas are one of the most common intracranial neoplasms. Although most of these tumors are benign and can be treated medically or by transsphenoidal surgery, a subset of these tumors are fast-growing, aggressive, recur, and remain a therapeutic dilemma. Because antibodies against immune checkpoint receptors PD-1 and CLTA-4 are now routinely used for cancer treatment, we quantified the expression of mRNA coding for PD-1, CLTA-4, and their ligands, PD-L1, PD-L2, CD80, and CD86 in human pituitary adenomas and normal pituitary glands, with the ultimate goal of exploiting immune checkpoint therapy in aggressive pituitary adenomas. Aggressive pituitary adenomas demonstrated an increased expression of PD-L2, CD80, and CD86 in compared to that of normal human pituitary glands. Furthermore, aggressive pituitary tumors demonstrated significantly higher levels of CD80 and CD86 compared to non-aggressive tumors. Our results establish a rationale for studying a potential role for immune checkpoint inhibition therapy in the treatment of pituitary adenomas.

Suppression of Transmembrane Tumor Necrosis Factor Alpha Processing by a Specific Antibody Protects Against Colitis-Associated Cancer.

Soluble tumor necrosis factor-α (sTNF-α) plays an important role in colitis-associated cancer (CAC); however, little is known about transmembrane TNF-α (tmTNF-α). Here, we observed an increase in sTNF-α mainly in colitis tissues from an azoxymethane/dextran sodium sulfate (DSS)-induced CAC mouse model whereas tmTNF-α levels were chiefly increased on epithelial cells at the tumor stage. The ratio of intracolonic tmTNF-α/sTNF-α was negatively correlated with the levels of pro-inflammatory mediators (IL-1ß, IL-6, and NO) and M1 macrophages but positively correlated with the infiltration of myeloid-derived suppressor cells, regulatory T cells, and the level of the anti-inflammatory cytokine IL-10, suggesting an anti-inflammatory effect of tmTNF-α. This effect of tmTNF-α was confirmed again by the induction of resistance to LPS in colonic epithelial cell lines NCM460 and HCoEpiC through the addition of exogenous tmTNF-α or transfection of the tmTNF-α leading sequence that lacks the extracellular segment but retains the intracellular domain of tmTNF-α. A tmTNF-α antibody was used to block tmTNF-α shedding after the first or second round of inflammation induction by DSS drinking to shift the time window of tmTNF-α expression ahead to the inflammation stage. Antibody treatment significantly alleviated inflammation and suppressed subsequent adenoma formation, accompanied by increased apoptosis. An antitumor effect was also observed when the antibody was administered at the malignant phase of CAC. Our results reveal tmTNF-α as a novel molecular marker for malignant transformation in CAC and provide a new insight into blocking the pathological process by targeting tmTNF-α processing.

Adenoma to carcinoma: A portrait of molecular and immunological profiles of colorectal sporadic tumors.

An in-depth investigation of the molecular and immunologic properties of colorectal adenoma is important for understanding the mechanisms of colorectal cancer (CRC) initiation and development through the adenoma pathway. We performed a meta-analysis of the gene expression data from seven CRC and colorectal sporadic conventional adenoma datasets. We compared the enrichment levels of immune signatures between adenoma, normal colon, and CRC, then applied immunohistochemistry to compare the CD3 + and CD8 + T cells infiltration using samples of adenoma, contiguous adenoma, and CRC. We identified differentially expressed genes (DEGs) between adenoma, normal colon, and CRC, then performed pathway, network, immune correlation, and survival analyses on the DEGs. Adenoma had lower enrichment levels of antitumor immune signatures (CD8 + T cells, NK cells, and MHC Class I) while higher levels of TGF-ß and Th17 signatures. Immunohistochemistry revealed variations in CD3 + and CD8 + T cells infiltration between low-grade and high-grade adenomas and between adenoma, normal colon, and CRC. We identified two groups of genes, which we named (NACupGs and NACdownGs), with consistent expression elevation and reduction respectively across the normal, precancerous, and cancerous stages. 48% of the NACupGs had expression levels highly correlated with Treg and TGF-ß immune signatures, of which 39% were inversely correlated with CRC survival. We conclude that anti-tumor immune response is reduced at the precancerous (adenoma) stage which is characterized by prominent TGF-ß and Th17 activity. The alterations of molecular and immunological profiles in adenoma can provide new insights into the initiation and development of CRC.

Immune Responses Vary in Preinvasive Colorectal Lesions by Tumor Location and Histology.

Immune responses vary in colorectal cancers, which strongly influence prognosis. However, little is known about the variance in immune response within preinvasive lesions. The study aims to investigate how the immune contexture differs by clinicopathologic features (location, histology, dysplasia) associated with progression and recurrence in early carcinogenesis. We performed a cross-sectional study using preinvasive lesions from the surgical pathology laboratory at the Medical University of South Carolina. We stained the tissues with immunofluorescence antibodies, then scanned and analyzed expression using automated image analysis software. We stained CD117 as a marker of mast cells, CD4/RORC to indicate Th17 cells, MICA/B as a marker of NK-cell ligands, and also used antibodies directed against cytokines IL6, IL17A, and IFNγ. We used negative binomial regression analysis to compare analyte density counts by location, histology, degree of dysplasia adjusted for age, sex, race, and batch. All immune markers studied (except IL17a) had significantly higher density counts in the proximal colon than distal colon and rectum. Increases in villous histology were associated with significant decreases in immune responses for IL6, IL17a, NK ligand, and mast cells. No differences were observed in lesions with low- and high-grade dysplasia, except in mast cells. The lesions of the proximal colon were rich in immune infiltrate, paralleling the responses observed in normal mucosa and invasive disease. The diminishing immune response with increasing villous histology suggests an immunologically suppressive tumor environment. Our findings highlight the heterogeneity of the immune responses in preinvasive lesions, which may have implications for prevention strategies. PREVENTION RELEVANCE: Our study is focused on immune infiltrate expression in preinvasive colorectal lesions; our results suggest important differences by clinicopathologic features that have implications for immune prevention research.

Alterations in CD8+ Tregs, CD56+ Natural Killer Cells and IL-10 Are Associated With Invasiveness of Nonfunctioning Pituitary Adenomas (NFPAs).

Invasive nonfunctioning pituitary adenomas (NFPAs) grow rapidly and the mechanisms are unclear. Among many complex mechanisms, the role of immunity in the development of NFPAs has not been fully explored. Here, we analyzed the clinical features 146 NFPA patients who underwent trans-sphenoidal surgery or craniotomy and examined the effects of immune tolerance in invasiveness of NFPA patients using fluorescence-activated cell sorting and immunohistochemical methods. We found patients with invasive NFPAs had more visual deficits and defective fields, higher tumor size, and lower white blood cell count compared with patients with noninvasive NFPAs. Additionally, compared with patients with noninvasive NFPAs, patients with invasive NFPAs had conspicuously lower CD3-CD56+ natural killer (NK) cells and significantly higher levels of CD3+CD8+CD28-T cells (CD8+ Tregs) and interleukin-10 (IL-10) in peripheral blood. Moreover, patients with invasive NFPAs had lower infiltrated CD56+ cells, less infiltrated CD28+ cells, and significantly greater IL-10 expression. These results demonstrated that low CD56+ cells infiltration and CD28+ cells infiltration, as well as high IL-10 expression in pituitary tumor tissues, were related with increased invasiveness of NFPAs. Levels of CD3-CD56+ NK cells, CD8+ Tregs and IL-10 in the peripheral blood could be feasible diagnostic markers for invasive NFPAs.

Dynamic stromal cellular reaction throughout human colorectal adenoma-carcinoma sequence: A role of TH17/IL-17A.

BACKGROUND: Accumulating data suggest that the tumour stroma rapidly undergoes dynamic mechanical and cellular changes by which creates a supportive milieu to promote disease progression and metastasis. Cytokines are reported to play a key role in the modulation of tumour stromal response. METHODS: The activation of TH17/interleukin (IL)-17A network in association with tumour stromal proliferative and cellular response in samples from 50 patients with colorectal adenoma, 45 with colorectal cancer (CRCs) were elucidated with quantitative real-time PCR (q-PCR), immunohistochemistry and double immunofluorescence. RESULTS: q-PCR results showed that retinoic acid-receptor-related orphan receptor-C, a critical transcriptional factor for TH17 cell differentiation, was significantly increased at the adenoma stage and slightly decreased at the CRC stage, but was still higher than that at normal controls. The level of TH17 signature cytokine IL-17A was shown in an increasing gradient throughout the adenoma-carcinoma sequence. Immunohistochemistry revealed an activated proliferative rate evaluated by Ki67 and population expansion of myofibroblasts in the adenoma/CRC stroma. Notably, densities of IL-17A-expressing cells were associated with populations of Ki67-positive cells and myofibroblasts in the adenoma/CRC stroma. Finally, CD146-positive stromal cells are an important participator for stroma remodelling, double immunofluorescence image demonstrated that IL-17 receptor C, one of the key elements for IL-17 receptor complex, was highly expressed in CD146-positive adenoma/CRC stromal cells. CONCLUSIONS: An activated TH17/IL-17A network in the tumour microenvironment is significantly associated with dynamic stromal cellular response throughout the adenoma-carcinoma sequence, which might provide a supportive environment for the initiation and progression of CRC.

Interleukin-11-expressing fibroblasts have a unique gene signature correlated with poor prognosis of colorectal cancer.

Interleukin (IL)-11 is a member of the IL-6 family of cytokines and is involved in multiple cellular responses, including tumor development. However, the origin and functions of IL-11-producing (IL-11+) cells are not fully understood. To characterize IL-11+ cells in vivo, we generate Il11 reporter mice. IL-11+ cells appear in the colon in murine tumor and acute colitis models. Il11ra1 or Il11 deletion attenuates the development of colitis-associated colorectal cancer. IL-11+ cells express fibroblast markers and genes associated with cell proliferation and tissue repair. IL-11 induces the activation of colonic fibroblasts and epithelial cells through phosphorylation of STAT3. Human cancer database analysis reveals that the expression of genes enriched in IL-11+ fibroblasts is elevated in human colorectal cancer and correlated with reduced recurrence-free survival. IL-11+ fibroblasts activate both tumor cells and fibroblasts via secretion of IL-11, thereby constituting a feed-forward loop between tumor cells and fibroblasts in the tumor microenvironment.

Organoids Are Limited in Modeling the Colon Adenoma-Carcinoma Sequence.

The colon adenoma-carcinoma sequence is a multistep genomic-altering process that occurs during colorectal cancer (CRC) carcinogenesis. Organoids are now commonly used to model both non-cancerous and cancerous tissue. This study aims to investigate how well organoids mimic tissues in the adenoma-carcinoma sequence by comparing their transcriptomes. A total of 234 tissue samples (48 adenomas and 186 CRC) and 60 organoid samples (15 adenomas and 45 CRC) were analyzed. We found that cell-proliferation-related gene sets were consistently enriched in both CRC tissues and organoids compared to adenoma tissues and organoids by gene set enrichment analysis (GSEA). None of the known pathways in the colon adenoma-carcinoma sequence were consistently enriched in CRC organoids. There was no enrichment of the tumor microenvironment-related gene sets in CRC organoids. CRC tissues enriched immune-response-related gene sets, whereas CRC organoids did not. The proportions of infiltrating immune cells were different between tissues and organoids, whereas there was no difference between cancer and adenoma organoids. The amounts of cancer stem cells and progenitor cells were not different between CRC and adenoma organoids, whereas a difference was noted between CRC and adenoma tissues. In conclusion, we demonstrated that organoids model only part of the adenoma-carcinoma sequence and should be used with caution after considering their limitations.

Impaired tumor immune response in metastatic tumors is a selective pressure for neutral evolution in CRC cases.

A Darwinian evolutionary shift occurs early in the neutral evolution of advanced colorectal carcinoma (CRC), and copy number aberrations (CNA) are essential in the transition from adenoma to carcinoma. In light of this primary evolution, we investigated the evolutionary principles of the genome that foster postoperative recurrence of CRC. CNA and neoantigens (NAG) were compared between early primary tumors with recurrence (CRCR) and early primary tumors without recurrence (precancerous and early; PCRC). We compared CNA, single nucleotide variance (SNV), RNA sequences, and T-cell receptor (TCR) repertoire between 9 primary and 10 metastatic sites from 10 CRCR cases. We found that NAG in primary sites were fewer in CRCR than in PCRC, while the arm level CNA were significantly higher in primary sites in CRCR than in PCRC. Further, a comparison of genomic aberrations of primary and metastatic conditions revealed no significant differences in CNA. The driver mutations in recurrence were the trunk of the evolutionary phylogenic tree from primary sites to recurrence sites. Notably, PD-1 and TIM3, T cell exhaustion-related molecules of the tumor immune response, were abundantly expressed in metastatic sites compared to primary sites along with the increased number of CD8 expressing cells. The postoperative recurrence-free survival period was only significantly associated with the NAG levels and TCR repertoire diversity in metastatic sites. Therefore, CNA with diminished NAG and diverse TCR repertoire in pre-metastatic sites may determine postoperative recurrence of CRC.

Colorectal Cancer Prevention in Lung Transplant Recipients: The Need for an Enhanced Surveillance Protocol.

BACKGROUND: Solid organ transplant recipients are at increased risk for noncutaneous neoplasms, including colorectal cancer (CRC). We evaluated precancerous lesions detected by post-transplant surveillance colonoscopy to infer the rate at which new adenomas develop in this population. STUDY DESIGN: We reviewed all patients who underwent lung transplant between January 2013 and August 2017 at our institution. Those with post-transplant survival <1 year, personal history of CRC, previous lung transplant, and lack of pretransplant colonoscopy were excluded. RESULTS: During the study period, 411 patients underwent lung transplant; 237 met inclusion criteria. Median age at transplant was 63.6 (interquartile range [IQR] 59.2-68.3) years. Most recipients were immunosuppressed with a combination of prednisone, tacrolimus, and mycophenolate mofetil. At least 1 adenoma was found in 92 patients (38.8%) pretransplant and in 118 patients (49.8%) from 1 to 5 years post-transplant, with 68.6% identified at 1 year. Most adenomas were identified proximal to the splenic flexure. Multiple (≥3) adenomas were found in 31.4% of positive colonoscopies. Within 5 years after transplant, patients with a positive pretransplant colonoscopy had significantly more positive post-transplant colonoscopies than patients with a negative pretransplant colonoscopy (63.0% vs 41.4%, p < 0.001). No de novo CRC was identified. CONCLUSIONS: Lung transplant recipients have a significantly higher risk of adenoma formation than average-risk adults (25%-30% national detection rate). This increase occurs in the early post-transplant period (within 3 years). An enhanced CRC surveillance protocol for lung transplant recipients is needed.

Immune checkpoint inhibitor therapy for ACTH-secreting pituitary carcinoma: a new emerging treatment?

BACKGROUND: Pituitary carcinomas are rare but aggressive and require maximally coordinated multimodal therapies. For refractory tumors, unresponsive to temozolomide (TMZ), therapeutic options are limited. Immune checkpoint inhibitors (ICI) may be considered for treatment as illustrated in the present case report. CASE: We report a patient with ACTH-secreting pituitary carcinoma, progressive after multiple lines of therapy including chemotherapy with TMZ, who demonstrated disease stabilization by a combination of ipilimumab (anti-CTLA-4) and nivolumab (anti-PD-1) ICI therapy. DISCUSSION: Management of pituitary carcinoma beyond TMZ remains ill-defined and relies on case reports. TMZ creates, due to hypermutation, more immunogenic tumors and subsequently potential candidates for ICI therapy. This case report adds support to the possible role of ICI in the treatment of pituitary carcinoma. CONCLUSION: ICI therapy could be a promising treatment option for pituitary carcinoma, considering the mechanisms of TMZ-induced hypermutation with increased immunogenicity, pituitary expression of CTLA-4 and PD-L1, and the frequent occurrence of hypophysitis as a side effect of ICI therapy.

Serrated Lesions in Inflammatory Bowel Disease: Genotype-Phenotype Correlation.

BACKGROUND: Patients with inflammatory bowel disease (IBD) and hyperplastic/serrated polyposis have an increased risk of colorectal cancer. The aim of our study was to elucidate the nature of serrated lesions in IBD patients. MATERIALS AND METHODS: Sixty-five lesions with serrated morphology were analyzed in 39 adult IBD patients. Lesions were classified according to the WHO 2019 criteria or regarded as reactive, and molecular analysis was performed. RESULTS: 82.1% of patients had ulcerative colitis, 17.9% had Crohn's disease; 51.3% were female, and the mean age was 54.5 years. The duration of IBD varied significantly (16.7 ± 11.4 years). Endoscopy showed polypoid lesions in 80.3%; the size ranged from 2 to 20 mm. A total of 21.6% of the lesions were located in the right colon. Five lesions were classified as inflammatory pseudopolyps, 28 as hyperplastic polyp, 21 and 2 as sessile serrated lesion without and with dysplasia, respectively, and 9 as traditional serrated adenoma with low-grade dysplasia. Analysis of all true serrated lesions revealed 31 mutations in KRAS and 32 in BRAF gene. No mutations were identified in inflammatory pseudopolyps. In the right colon BRAF mutations were more frequent than KRAS (16 vs 3), while KRAS mutations prevailed on the left side (28 vs 16, P < .001). One patient with traditional serrated adenomas progressed to an adenocarcinoma after 61 months. CONCLUSION: The molecular analysis could help discriminate true serrated lesions (IBD-associated or not) from reactive pseudopolyps with serrated/hyperplastic epithelial change. These should help in more accurate classification of serrated lesions.

Inflammation Modulation by Vitamin D and Calcium in the Morphologically Normal Colorectal Mucosa of Patients with Colorectal Adenoma in a Clinical Trial.

Increased COX-2 and decreased 15-hydroxyprostaglandin dehydrogenase (15-HPGD) expression promote prostaglandin-mediated inflammation and colorectal carcinogenesis. Experimental studies suggest that vitamin D and calcium may inhibit these pathways, but their effects on colorectal tissue COX-2 and 15-HPGD expression in humans are unknown. We tested the effects of supplemental vitamin D (1,000 IU/day) and/or calcium (1,200 mg/day) on COX-2 and 15-HPGD expression in the morphologically normal rectal mucosa from 62 paients with colorectal adenoma in a placebo-controlled chemoprevention trial. We measured biomarker expression using automated IHC and quantitative image analysis at baseline and 1-year follow-up, and assessed treatment effects using mixed linear models. The primary outcome was the COX-2/15-HPGD expression ratio, because these enzymes function as physiologic antagonists. After 1 year of treatment, the mean COX-2/15-HPGD expression ratio in full-length crypts proportionately decreased 47% in the vitamin D group (P = 0.001), 46% in the calcium group (P = 0.002), and 34% in the calcium + vitamin D group (P = 0.03), relative to the placebo group. Among individuals with the functional vitamin D-binding protein isoform DBP2 (GC rs4588*A), the COX-2/15-HPDG ratio decreased 70% (P = 0.0006), 75% (P = 0.0002), and 60% (P = 0.006) in the vitamin D, calcium, and combined supplementation groups, respectively, relative to placebo. These results show that vitamin D and calcium favorably modulate the balance of expression of COX-2 and 15-HPGD-biomarkers of inflammation that are strongly linked to colorectal carcinogenesis-in the normal-appearing colorectal mucosa of patients with colorectal adenoma (perhaps especially those with the DBP2 isoform). PREVENTION RELEVANCE: Supplemental calcium and vitamin D reduce indicators of cancer-promoting inflammation in normal colorectal tissue in humans, thus furthering our understanding of how they may help prevent colorectal cancer.

Comprehensive analysis of the immunological landscape of pituitary adenomas: implications of immunotherapy for pituitary adenomas.

PURPOSES: Immunotherapies for solid tumor are gaining traction in the clinic, however, the immunological landscape of pituitary adenomas (PAs) is not well defined. In the present study, we used the RNA-seq data of PAs to investigate the impact of immunological landscape on clinical features of pituitary adenomas and aim to evaluate the potential immunotherapy for PAs. METHODS: We analyzed tumor-infiltrating immune cells in 115 PA samples using RNA-seq. Main immune cell types (B cells, CD8+ T cells, CD4+ T cells, macrophages and NK cells) were detected from the expression of genes. The association between immune cells abundance and immune checkpoint, as well as inflammatory factors were analyzed. 10 additional patients were enrolled for validation. RESULTS: In RNA sequencing data, landscape of PAs were identified. Our computationally inferred immune infiltrates significantly associate with patient clinical features. Growth hormone-secreting adenomas (GHomas) were found with higher B cells and CD8+ T cells infiltration. Moreover, GHomas showed relative different genetic background, significant invasive behavior and independently correlated with reduced progress-free time. Tumor progression was related to increased expression of PD-1/PD-L1 and was associated with higher immune infiltration. Analysis of cancer-testis antigen expression and CD8+ T-cell abundance suggested CTAG2 and TSPYL6 were potential immunotherapeutic targets in GHomas and non-functioning adenomas, respectively. CONCLUSIONS: Tumor-infiltrating immune cells confer important clinical and biological implications. Our results of immune-infiltrate levels in PAs may inform effective cancer vaccine and checkpoint blockade therapies and make it possible to take immunotherapy into invasive PAs.

The GM-CSF-IRF5 signaling axis in eosinophils promotes antitumor immunity through activation of type 1 T cell responses.

The depletion of eosinophils represents an efficient strategy to alleviate allergic asthma, but the consequences of prolonged eosinophil deficiency for human health remain poorly understood. We show here that the ablation of eosinophils severely compromises antitumor immunity in syngeneic and genetic models of colorectal cancer (CRC), which can be attributed to defective Th1 and CD8+ T cell responses. The specific loss of GM-CSF signaling or IRF5 expression in the eosinophil compartment phenocopies the loss of the entire lineage. GM-CSF activates IRF5 in vitro and in vivo and can be administered recombinantly to improve tumor immunity. IL-10 counterregulates IRF5 activation by GM-CSF. CRC patients whose tumors are infiltrated by large numbers of eosinophils also exhibit robust CD8 T cell infiltrates and have a better prognosis than patients with eosinophillow tumors. The combined results demonstrate a critical role of eosinophils in tumor control in CRC and introduce the GM-CSF-IRF5 axis as a critical driver of the antitumor activities of this versatile cell type.

Streptococcus bovis Contributes to the Development of Colorectal Cancer via Recruiting CD11b⁺TLR-4⁺ Cells.

BACKGROUND An increasing number of studies have demonstrated that Streptococcus bovis and its concomitant inflammatory factors concentrate in the intestine in colorectal cancer (CRC). However, the molecular mechanism of S. bovis on colorectal tumorigenesis remains unclear. This study aimed to explore the role of S. bovis in carcinogenesis and its potential mechanism in CRC of mice orally pretreated with S. bovis. MATERIAL AND METHODS The colons of experimental mice were collected and evaluated for the extent of neoplasm. In addition, comparative feces DNA sequencing was adopted to verify the abundance change of S. bovis during the progression of CRC in patients. RESULTS The results of this study found that S. bovis is more likely to be present at higher levels in patients with progressive colorectal carcinoma compared to those adenoma patients and healthy volunteers (P<0.05). Pretreatment with S. bovis aggravated tumor formation in mice, resulting in more substantial and a higher number of tumor nodes (P<0.05). A cytokine expression pattern with increased levels of IL-6, Scyb1, Ptgs2, IL-1ß, TNF, and Ccl2 was detected in S. bovis pretreated CRC mice (all P<0.05). Furthermore, S. bovis recruited myeloid cells, especially CD11b⁺TLR-4⁺ cells, which could promote pro-tumor immunity in the tumor microenvironment (P<0.05). CONCLUSIONS Collectively, our study indicates that S. bovis may induce a suppressive immunity that is conducive to CRC by recruiting tumor-infiltrating CD11b⁺TLR-4⁺ cells. In conclusion, S. bovis contributes to colorectal tumorigenesis via recruiting CD11b⁺TLR-4⁺ cells.

The Immune Profile of Pituitary Adenomas and a Novel Immune Classification for Predicting Immunotherapy Responsiveness.

CONTEXT: The tumor immune microenvironment is associated with clinical outcomes and immunotherapy responsiveness. OBJECTIVE: To investigate the intratumoral immune profile of pituitary adenomas (PAs) and its clinical relevance and to explore a novel immune classification for predicting immunotherapy responsiveness. DESIGN, PATIENTS, AND METHODS: The transcriptomic data from 259 PAs and 20 normal pituitaries were included for analysis. The ImmuCellAI algorithm was used to estimate the abundance of 24 types of tumor-infiltrating immune cells (TIICs) and the expression of immune checkpoint molecules (ICMs). RESULTS: The distributions of TIICs differed between PAs and normal pituitaries and varied among PA subtypes. T cells dominated the immune microenvironment across all subtypes of PAs. The tumor size and patient age were correlated with the TIIC abundance, and the ubiquitin-specific protease 8 (USP8) mutation in corticotroph adenomas influenced the intratumoral TIIC distributions. Three immune clusters were identified across PAs based on the TIIC distributions. Each cluster of PAs showed unique features of ICM expression that were correlated with distinct pathways related to tumor development and progression. CTLA4/CD86 expression was upregulated in cluster 1, whereas programmed cell death protein 1/programmed cell death 1 ligand 2 (PD1/PD-L2) expression was upregulated in cluster 2. Clusters 1 and 2 exhibited a "hot" immune microenvironment and were predicted to exhibit higher immunotherapy responsiveness than cluster 3, which exhibited an overall "cold" immune microenvironment. CONCLUSIONS: We summarized the immune profile of PAs and identified 3 novel immune clusters. These findings establish a foundation for further immune studies on PAs and provide new insights into immunotherapy strategies for PAs.