B7-H3 immune checkpoint expression is a poor prognostic factor in colorectal carcinoma

B7H4 Role in Solid Cancers: A Review of the Literature

Anti-cancer immunotherapies entirely changed the therapeutic approach to oncological patients. However, despite the undeniable success of anti-PD-1, PD-L1, and CTLA-4 antibody treatments, their effectiveness is limited either by certain types of malignancies or by the arising problem of cancer resistance. B7H4 (aliases B7x, B7H4, B7S1, VTCN1) is a member of a B7 immune checkpoint family with a distinct expression pattern from classical immune checkpoint pathways. The growing amount of research results seem to support the thesis that B7H4 might be a very potent therapeutic target. B7H4 was demonstrated to promote tumour progression in immune "cold" tumours by promoting migration, proliferation of tumour cells, and cancer stem cell persistence. B7H4 suppresses T cell effector functions, including inflammatory cytokine production, cytolytic activity, proliferation of T cells, and promoting the polarisation of naïve CD4 T cells into induced Tregs. This review aimed to summarise the available information about B7H4, focusing in particular on clinical implications, immunological mechanisms, potential strategies for malignancy treatment, and ongoing clinical trials.

Incorporating IL7 receptor alpha signaling in the endodomain of B7H3-targeting chimeric antigen receptor T cells mediates antitumor activity in glioblastoma

CAR-T-cell therapy has shown promise in treating hematological malignancies but faces challenges in treating solid tumors due to impaired T-cell function in the tumor microenvironment. To provide optimal T-cell activation, we developed a B7 homolog 3 protein (B7H3)-targeting CAR construct consisting of three activation signals: CD3ζ (signal 1), 41BB (signal 2), and the interleukin 7 receptor alpha (IL7Rα) cytoplasmic domain (signal 3). We generated B7H3 CAR-T cells with different lengths of the IL7Rα cytoplasmic domain, including the full length (IL7R-L), intermediate length (IL7R-M), and short length (IL7R-S) domains, and evaluated their functionality in vitro and in vivo. All the B7H3-IL7Rα CAR-T cells exhibited a less differentiated phenotype and effectively eliminated B7H3-positive glioblastoma in vitro. Superiority was found in B7H3 CAR-T cells contained the short length of the IL7Rα cytoplasmic domain. Integration of the IL7R-S cytoplasmic domain maintained pSTAT5 activation and increased T-cell proliferation while reducing activation-induced cell death. Moreover, RNA-sequencing analysis of B7H3-IL7R-S CAR-T cells after coculture with a glioblastoma cell line revealed downregulation of proapoptotic genes and upregulation of genes associated with T-cell proliferation compared with those in 2nd generation B7H3 CAR-T cells. In animal models, compared with conventional CAR-T cells, B7H3-IL7R-S CAR-T cells suppressed tumor growth and prolonged overall survival. Our study demonstrated the therapeutic potential of IL7Rα-incorporating CAR-T cells for glioblastoma treatment, suggesting a promising strategy for augmenting the effectiveness of CAR-T cell therapy.

B7-H3 at the crossroads between tumor plasticity and colorectal cancer progression: a potential target for therapeutic intervention

B7-H3 (B7 homology 3 protein) is an important transmembrane immunoregulatory protein expressed in immune cells, antigen-presenting cells, and tumor cells. Studies reveal a multifaceted role of B7-H3 in tumor progression by modulating various cancer hallmarks involving angiogenesis, immune evasion, and tumor microenvironment, and it is also a promising candidate for cancer immunotherapy. In colorectal cancer (CRC), B7-H3 has been associated with various aspects of disease progression, such as evasion of tumor immune surveillance, tumor-node metastasis, and poor prognosis. Strategies to block or interfere with B7-H3 in its immunological and non-immunological functions are under investigation. In this study, we explore the role of B7-H3 in tumor plasticity, emphasizing tumor glucose metabolism, angiogenesis, epithelial-mesenchymal transition, cancer stem cells, apoptosis, and changing immune signatures in the tumor immune landscape. We discuss how B7-H3-induced tumor plasticity contributes to immune evasion, metastasis, and therapy resistance. Furthermore, we delve into the most recent advancements in targeting B7-H3-based tumor immunotherapy as a potential approach to CRC treatment.

New Emerging Targets in Cancer Immunotherapy: The Role of B7-H3

Immune checkpoints (ICs) are molecules implicated in the fine-tuning of immune response via co-inhibitory or co-stimulatory signals, and serve to secure minimized host damage. Targeting ICs with various therapeutic modalities, including checkpoint inhibitors/monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), and CAR-T cells has produced remarkable results, especially in immunogenic tumors, setting a paradigm shift in cancer therapeutics through the incorporation of these IC-targeted treatments. However, the large proportion of subjects who experience primary or secondary resistance to available IC-targeted options necessitates further advancements that render immunotherapy beneficial for a larger patient pool with longer duration of response. B7-H3 (B7 Homolog 3 Protein, CD276) is a member of the B7 family of IC proteins that exerts pleiotropic immunomodulatory effects both in physiologic and pathologic contexts. Mounting evidence has demonstrated an aberrant expression of B7-H3 in various solid malignancies, including tumors less sensitive to current immunotherapeutic options, and has associated its expression with advanced disease, worse patient survival and impaired response to IC-based regimens. Anti-B7-H3 agents, including novel mAbs, bispecific antibodies, ADCs, CAR-T cells, and radioimmunotherapy agents, have exhibited encouraging antitumor activity in preclinical models and have recently entered clinical testing for several cancer types. In the present review, we concisely present the functional implications of B7-H3 and discuss the latest evidence regarding its prognostic significance and therapeutic potential in solid malignancies, with emphasis on anti-B7-H3 modalities that are currently evaluated in clinical trial settings. Better understanding of B7-H3 intricate interactions in the tumor microenvironment will expand the oncological utility of anti-B7-H3 agents and further shape their role in cancer therapeutics.

B7-H3 regulates anti-tumor immunity and promotes tumor development in colorectal cancer

Colorectal cancer (CRC) is a common malignant tumor of the gastrointestinal tract and one of the most common causes of cancer-related deaths worldwide. Immune checkpoint inhibitors have become a milestone in many cancer treatments with significant curative effects. However, its therapeutic effect on colorectal cancer is still limited. B7-H3 is a novel immune checkpoint molecule of the B7/CD28 family and is overexpressed in a variety of solid tumors including colorectal cancer. B7-H3 was considered as a costimulatory molecule that promotes anti-tumor immunity. However, more and more studies support that B7-H3 is a co-inhibitory molecule and plays an important immunosuppressive role in colorectal cancer. Meanwhile, B7-H3 promoted metabolic reprogramming, invasion and metastasis, and chemoresistance in colorectal cancer. Therapies targeting B7-H3, including monoclonal antibodies, antibody drug conjugations, and chimeric antigen receptor T cells, have great potential to improve the prognosis of colorectal cancer patients.

Soluble B7-H3 in Colorectal Cancer

We present the results of comparative ELISA of the concentration of soluble form of immunity checkpoint B7-H3 (sB7-H3) in the serum of patients with colorectal cancer (CRC) at different stages before treatment and healthy control donors. The analysis revealed a statistically significant difference between the median levels of sB7-H3 in the blood serum of CRC patients (19.66 ng/ml) and healthy donors (16.76 ng/ml) (p=0.0025). ROC analysis showed 62.9% sensitivity and 56.7% specificity for CRC patients (cut-off 17.62 ng/ml; p=0.0028). An association of sB7-H3 levels with tumor progression was revealed. We demonstrated that sB7-H3 levels were significantly lower in patients with regional metastases than in patients without metastases (p=0.039) and that sB7-H3 concentration tends to decrease at the late stages of the disease. Thus, high serum level of sB7-H3 in CRC patients can be a favorable prognostic factor in future.

Anti-PD-1 therapy for advanced colorectal cancer based on intestinal microecology

To explore the effects of anti-programmed death-1 (PD-1) therapy on advanced colorectal cancer (CRC) based on the intestinal microecology. Ninety-two patients with advanced CRC were selected. Patients were treated with Apatinib alone or anti PD-1 treatment combined with Apatinib. The lactulose/mannitol (L/M) value of the urine was detected by high performance liquid chromatography. The changes of intestinal microflora were determined by real-time fluorescence quantitative PCR. The risk factors were analyzed through multivariate logistic regression analysis. The curative effect of anti PD-1 treatment combined with the Apatinib treatment (82.61%) was much higher than that of the Apatinib treatment alone (63.04%, p < 0.05). After treatment, the contents of Bifidobacterium, Lactobacillus, and Enterococcus faecalis were higher with lower levels of Escherichia coli in the observation group than the control (p < 0.05). The level of D-lactic acid and urinary L/M value of the urine in the observation group was lower than that in control after treatment (p < 0.001). The patients had a 3-year survival rate of 91.30%. Age >60 years old, histological types of mucinous adenocarcinoma and signet ring cell carcinoma, vascular tumor thrombus, nerve invasion, TNM stage of Ⅲ-Ⅳ were independent risk factors, and anti PD-1 treatment was the protective factor (p < 0.05). In advanced CRC patients receiving anti PD-1 treatment combined with the Apatinib treatment, the progression of advanced CRC was effectively controlled by maintaining the intestinal microflora balance. Anti PD-1 therapy can improve the living quality of CRC patients.

Homologous recombination repair gene mutations in colorectal cancer favors treatment of immune checkpoint inhibitors

Immune checkpoint inhibitor (ICI) therapy is insensitive for Colorectal cancer (CRC) patients with microsatellite stable (MSS). Genomic data of three CRC cohort, n = 35), and the Cancer Genome Atlas (TCGA CRC cohort, n = 377), were analyzed. A cohort treated with ICIs from Memorial Sloan Kettering Cancer Center (MSKCC CRC cohort, n = 110) and two cases from the local hospital were characterized the impact of the HRR mutation on prognosis of CRC. Homologous recombination repair (HRR) gene mutations were more common in CN and HL cohorts (27.85%; 48.57%) than in TCGA CRC cohort (15.92%), especially in the MSS populations, the frequencies of HRR mutation were higher in CN and HL cohort (27.45%, 51.72%) than in TCGA cohort (6.85%). HRR mutations were associated with high tumor mutational burden (TMB-H). Although HRR mutation uncorrelated with an improved overall survival in the MSKCC CRC cohort (p = 0.97), HRR mutated patients had a significantly improved OS compared to the HRR wildtype population particularly in MSS subgroups (p = 0.0407) under ICI treatment. It probably contributed by a higher neoantigen and increased CD4+ T cell infiltration which found in the TCGA MSS HRR mutated CRC cohort. The similar phenomenon on cases was observed that MSS metastatic CRC patient with HRR mutation seemed more sensitive to ICI after multi-line chemotherapy in clinical practice than HRR wildtype. This finding suggests the feasibility of HRR mutation as an immunotherapy response predictor in MSS CRC, which highlights a potential therapeutic approach for these patients.

B7H3 Role in Reshaping Immunosuppressive Landscape in MSI and MSS Colorectal Cancer Tumours

The study aimed to assess the expression of B7H3 concerning clinicopathological and histological parameters, including MSI/MSS status, CD-8 cells, tumour-infiltrating lymphocytes (TILs), budding, TNM scale and grading. Moreover, we analyzed the B7H3-related pathways using available online datasets and the immunological context of B7H3 expression, through the 48-cytokine screening panel of cancer tissues homogenates, immunogenic features and immune composition. The study included 158 patients diagnosed with CRC. To assess B7H3 levels, we performed an immunohistochemistry method (IHC) and enzyme-linked immunosorbent assay (ELISA). To elucidate the immune composition of colorectal cancer, we performed the Bio-Plex Pro Human 48-cytokine panel. To study biological characteristics of B7H3, we used online databases. Expression of B7H3 was upregulated in CRC tumour tissues in comparison to adjacent noncancerous margin tissues. The concentrations of B7H3 in tumours were positively associated with T parameter of patients and negatively with tumour-infiltrating lymphocytes score. Additionally, Principal Component Analysis showed that B7H3 expression in tumours correlated positively with cytokines associated with M2-macrophages and protumour growth factors. The expression of B7H3 in tumours was independent of MSI/MSS status. These findings will improve our understanding of B7H3 role in colorectal cancer immunity. Our study suggests that B7-H3 is a promising potential target for cancer therapy. Further studies must clarify the mechanisms of B7H3 overexpression and its therapeutic importance in colorectal cancer.

Tumour necrosis factor stimulated gene 6 intrinsically regulates PD-L1 expressions in breast cancer cells, leading to modulation of tumour microenvironment

Recent studies have shown that tumour cells express tumour necrosis factor-inducible gene 6 (TSG-6) and its protein, which is known to play a key role in regulating excessive immune responses and proliferation and growth of mesenchymal stem cells (MSCs). It has not been confirmed whether the inhibition of TSG-6 for tumour cells can suppress tumour cell growth and regulate the activation of immune cells in the tumour microenvironment (TME). TSG-6-specific small interfering RNA was transfected into canine and human breast cancer cells (CIPp, CIPm and BT-20). TSG-6-down-regulated (siTSG-6) cells showed decreased cell proliferation, migration, and invasion abilities. Decreased mRNA expressions of NF-κB, STAT3 and Sox2, confirming that TSG-6 is an upper factor governing tumour growth and metastasis. Notably, siTSG-6 cells showed significantly decreased expression levels of CD44 and PD-L1. Direct and indirect co-culture of canine peripheral blood mononuclear cells (cPBMCs) and the siTSG-6 cells showed significant activation in M1 type macrophages and cytotoxic T cells. They also showed a tendency to decrease in the expression of CTLA-4 and increase in the expression of PD-1. In conclusion, this study suggests that the down-regulation of TSG-6 in breast cancer cells could not only suppress tumour growth and metastasis, and but also regulate TME. Since modulation of immune checkpoint proteins occurs in both tumour cells and immune cells, inhibiting TSG-6 and its protein within the TME could be novel therapeutic target for anticancer treatment.

Expression and Prognostic Value of B7 Family Immune Checkpoints in Pancreatic Neuroendocrine Tumors

CONTEXT.—

Pancreatic neuroendocrine tumors (PanNETs) are rare malignancies with heterogeneous clinical courses requiring novel prognosticators and therapies. B7 family molecules have an important role in various cancers; however, these have not been distinguished in PanNETs.

OBJECTIVE.—

To investigate the expression and clinical significance of programmed death ligand-1 (PD-L1), programmed death ligand-2 (PD-L2), B7 homolog 3 (B7-H3), B7 homolog 4 (B7-H4), and V-domain immunoglobulin suppressor of T-cell activation (VISTA) in 182 PanNETs (with a high proportion of functioning versus nonfunctioning PanNETs: 51% versus 49%).

DESIGN.—

Molecules were immunostained by using tissue microarrays from 182 patients with grade 1/2 PanNETs. VISTA-positive microvessel density (VISTA+ MVD) was evaluated in 4 high-power fields (HPFs) (×200) and mean count was calculated; immune cells with 1% or greater VISTA staining were considered positive. PD-L1 tumoral expression was considered positive in samples with 5% or more membranous staining. Tumoral VISTA, stromal PD-L1, PD-L2, B7-H3, and B7-H4 expression were deemed positive if any staining was observed.

RESULTS.—

VISTA+ MVD was high (≥10.8/HPF) in 45 patients (25%), while VISTA stained positively on immune and tumor cells in 121 (66%) and 0 patients, respectively. Positive PD-L1 tumoral and stromal expression was observed in 23 (13%) and 0 patients, with positive B7-H3 expression in 76 (42%) and 98 (54%) patients, respectively, in these cells; PD-L2 and B7-H4 were not detected. PD-L1 positivity rate was high in functioning PanNETs. Stromal B7-H3 and high VISTA+ MVD correlated with unfavorable clinicopathologic features. Moreover, high VISTA+ MVD was an independent predictor of shorter progression-free survival.

CONCLUSIONS.—

VISTA may serve as a prognosticator and immunotherapeutic target for patients with pancreatic neuroendocrine tumor (PanNET).

Significance of Siglec-15 expression in colorectal cancer: association with advanced disease stage and fewer tumor-infiltrating lymphocytes

Siglec-15, a novel immune suppressor, is upregulated in many human cancers. The aim of this study was to explore the expression of Siglec-15 in colorectal cancer (CRC), and investigate whether Siglec-15 could be a potential target for cancer immunotherapy in patients with CRC. We performed immunohistochemical analyses of Siglec-15 on a cohort of 805 patients with CRC and made comparisons between clinicopathological characteristics, PD-L1 expression, CD3, CD8, CD45RO tumor-infiltrating lymphocytes (TILs), and prognosis. We found that Siglec-15 expression was commonly detected in tumor cells (48.3%) and tumor-associated stromal cells (33.4%), and was more frequently observed than PD-L1 expression in tumor cells. In contrast, Siglec-15 expression was weakly and scarcely found in normal mucosa (13%). Siglec-15 overexpression in tumor cells was associated with advanced TNM stage (p = 0.020). Co-expression of Siglec-15 and PD-L1 in tumor cells was found in 14.4% of patients, and Siglec-15 expression was detected in almost half of PD-L1 negative cases. Elevated Siglec-15 expression in tumor and stromal cells was associated with sparser CD45RO and CD8 TILs (p = 0.035 and p = 0.004, respectively). The expression of Siglec-15 did not have prognostic significance. In summary, compared to PD-L1, Siglec-15 protein expression is more prevalent in CRC and is associated with advanced disease stage and fewer TILs. These findings support Siglec-15 as a potential cancer immunotherapy target, in addition to PD-1/PD-L1 inhibitors, in patients with CRC.

Immune checkpoint of B7-H3 in cancer: from immunology to clinical immunotherapy

Immunotherapy for cancer is a rapidly developing treatment that modifies the immune system and enhances the antitumor immune response. B7-H3 (CD276), a member of the B7 family that plays an immunoregulatory role in the T cell response, has been highlighted as a novel potential target for cancer immunotherapy. B7-H3 has been shown to play an inhibitory role in T cell activation and proliferation, participate in tumor immune evasion and influence both the immune response and tumor behavior through different signaling pathways. B7-H3 expression has been found to be aberrantly upregulated in many different cancer types, and an association between B7-H3 expression and poor prognosis has been established. Immunotherapy targeting B7-H3 through different approaches has been developing rapidly, and many ongoing clinical trials are exploring the safety and efficacy profiles of these therapies in cancer. In this review, we summarize the emerging research on the function and underlying pathways of B7-H3, the expression and roles of B7-H3 in different cancer types, and the advances in B7-H3-targeted therapy. Considering different tumor microenvironment characteristics and results from preclinical models to clinical practice, the research indicates that B7-H3 is a promising target for future immunotherapy, which might eventually contribute to an improvement in cancer immunotherapy that will benefit patients.

PD-L1 Expression in Colorectal Adenocarcinoma Is Associated With the Tumor Immune Microenvironment and Epithelial-Mesenchymal Transition

OBJECTIVES

Colorectal carcinomas are the third-most common tumors in the world, and colorectal cancer ranks second in cancer-related deaths. Our aim in this study was to investigate the correlation between programmed cell death ligand 1 (PD-L1) expression and clinicopathologic parameters in colorectal carcinomas and their relationship to the tumor immune microenvironment, epithelial-mesenchymal transition (EMT), and microsatellite instability. We also investigated the predictive and prognostic role of PD-L1.

METHODS

One hundred patients with a diagnosis of colorectal adenocarcinoma who did not receive neoadjuvant therapy were included in the study. The relationships among the altered expression of PD-L1; vimentin; E-cadherin; mismatch repair status; and pathologic microenvironmental features, including the presence of tumor budding and CD8-positive tumor infiltrating lymphocytes (TILs), were assessed.

RESULTS

Increased PD-L1 expression in tumor cells was associated with increased TILs (P = .013), high histologic grade (P = .011), advanced pathologic T stage (P = .007), lymph node metastasis (P = .002), distant metastasis (P < .001), perineural invasion (P = .009), high bud score (P = .023), EMT (P < .001), and shorter disease-free survival (P = .029).

CONCLUSIONS

Overall, PD-L1 expression in colorectal carcinoma tumor cells is a marker of poor prognosis, and the positive correlation detected between EMT status and PD-L1 expression suggests that patients with the mesenchymal phenotype may be more likely to benefit from programmed cell death 1 protein/PD-L1 immunotherapy.

Prognostic values of B7-H3, B7-H4, and HHLA2 expression in human pancreatic cancer tissues based on mIHC and spatial distribution analysis

BACKGROUND

Pancreatic cancer (PC) is one of the most malignant solid tumors and its 5-year survival rate remains poor. Although immunotherapy has achieved certain therapeutic efficacy in some clinical trials, such treatment still shows low responses and overall remission rate. Therefore, it is urgently necessary to dissect the tumor microenvironment and optimize the immunotherapeutic strategies against this malignancy.

METHODS

Using the multi-color immunohistochemistry assay, we investigated the expressions of B7-H3, B7-H4, HHLA2, CD8, and CD68 in 63 cases of PC tissues in a tissue microarray. Moreover, we analyzed immunolocalization features, clinical associations and prognostic values of these molecules.

RESULTS

The expressions of B7-H3, B7-H4, and HHLA2 could be detected in cytokeratin staining positive (CK+) cancer epithelial cells, CD68+tumor-associated macrophages (TAMs), and even other cells defined as CK-CD8-CD68-. Higher expression of B7-H3 in tumor cells could predict a better survival of the PC patients. A positive correlation was found between the expressions of B7-H3 and HHLA2 in tumor cells, while there was a negative correlation between the expressions of B7-H4 and HHLA2 in tumor cells. A positive correlation was found between the expressions of B7-H3 and B7-H4 or HHLA2 in CD68+TAMs, but not B7-H4 and HHLA2. Tumor-infiltrating CD8+T cells in combination with CD68+TAMs could serve as an important predictor for the postoperative prognosis of PC patients. Higher expression of B7-H3, or HHLA2 in CD68+TAMs could serve as an important predictor for poorer prognosis of PC patients. Patients with B7-H3lowB7-H4low, B7-H3lowHHLA2low, or B7-H4lowHHLA2low on CD68+TAMs could have a better postoperative prognosis compared with the other sub-populations in the combinational analysis.

CONCLUSIONS

Taken together, our study indicated variable expressions and prognostic values of B7-H3, B7-H4, and HHLA2, in human PC tissues, and demonstrated that these co-stimulator molecules expressed by CD68+TAMs could be used as important bio-markers for the prognostic prediction of PC patients. Moreover, these results supported that the evaluation of these markers could be used as essential candidate targets for immunotherapy against PC.

Expression of B7 family checkpoint proteins in cervical cancer

The role of programmed cell death-ligand 1 (PD-L1) in cervical cancer has been widely investigated; however, the influences of other inhibitory B7 family members are poorly understood. We investigated the expression of PD-L1, B7 homolog 3 (B7-H3), B7-H4, and V-domain Ig suppressor of T-cell activation (VISTA) and their association with the clinicopathological features and outcomes of a large cohort of 673 patients with squamous cell carcinoma or adenocarcinoma of the uterine cervix. The positivity rates for PD-L1 (combined positive score ≥1), B7-H3 in tumor cells (TCs), B7-H4 (exclusively in TCs), VISTA in immune cells (ICs), and VISTA in TCs were 57.9%, 62.8%, 44.8%, 92.6%, and 4.8%, respectively, in 606 primary cervical cancer samples. Co-expression of PD-L1 with B7-H3 in TCs and with B7-H4 and VISTA in ICs was observed in 38.8%, 25.4%, and 57.9% of samples, respectively. B7-H3 in TCs and B7-H4 and VISTA in ICs were observed in 58.1%, 46.6%, and 83.1% of PD-L1-negative samples, respectively. These proteins were observed more frequently in squamous cell carcinomas and in moderately to poorly differentiated carcinomas. VISTA (in ICs) and B7-H4 were more frequent in primary tumors than in recurrent counterparts and correlated with improved survival; in contrast, B7-H3 positivity in TCs was less frequent in primary tumors and correlated with short disease-specific survival. Co-expression of B7-H4 and VISTA in ICs was an independent predictor of favorable outcomes overall and among patients with PD-L1-negative tumors. These data indicate that B7 family proteins exhibit differing expression patterns, distributions, and prognostic implications in cervical cancer. Furthermore, the co-expression of PD-L1 with other checkpoint proteins suggests that PD-1/PD-L1 blockade combined with modulating other immune checkpoints may present a novel therapeutic approach for cervical cancer. Future studies are needed to validate prognostic values of B7 family proteins and explore their biological roles in this malignancy.

Tumor Microenvironment Profiles Reveal Distinct Therapy-Oriented Proteogenomic Characteristics in Colorectal Cancer

Advances in immunotherapy have made an unprecedented leap in treating colorectal cancer (CRC). However, more effective therapeutic regimes need a deeper understanding of molecular architectures for precise patient stratification and therapeutic improvement. We profiled patients receiving neoadjuvant chemotherapy alone or in combination with immunotherapy (PD-1 checkpoint inhibitor) using Digital Spatial Profiler (DSP), a high-plex spatial proteogenomic technology. Compartmentalization-based high-plex profiling of both proteins and mRNAs revealed pronounced immune infiltration at tumor regions associated with immunotherapy treatment. The protein and the corresponding mRNA levels within the same selected regions of those patient samples correlate, indicating an overall concordance between the transcriptional and translational levels. An elevated expression of PD-L1 at both protein and the mRNA levels was discovered in the tumor compartment of immunotherapy-treated patients compared with chemo-treated patients, indicating potential prognostic biomarkers are explorable in a spatial manner at the local tumor microenvironment (TME). An elevated expression of PD-L1 was verified by immunohistochemistry. Other compartment-specific biomarkers were also differentially expressed between the tumor and stromal regions, indicating a dynamic interplay that can potentiate novel biomarker discovery from the TME perspectives. Simultaneously, a high-plex spatial profiling of protein and mRNA in the tumor microenvironment of colorectal cancer was performed.

Tumor B7-H3 expression in diagnostic biopsy specimens and survival in patients with metastatic prostate cancer

BACKGROUND

Prostate cancer spans a broad spectrum from indolent to deadly disease. In the management of prostate cancer, diagnostic biopsy specimens are important sources of data that inform the selection of treatment. B7-H3 (CD276), an immune checkpoint molecule, has emerged as a promising immunotherapy target. B7-H3 expression is related to adverse clinical outcomes in various types of cancer; however, little is known concerning the association between tumor B7-H3 expression in diagnostic biopsy specimens and clinical outcome in patients with metastatic prostate cancer.

METHODS

We evaluated tumor B7-H3 expression levels in diagnostic biopsy specimens from 135 patients with metastatic prostate cancer and 113 patients with localized prostate cancer.

RESULTS

High B7-H3 expression was more frequently observed in patients with metastatic cancer than in those with localized cancer (31 vs. 12%; p = 0.0003). In patients with localized cancer, the B7-H3 expression status was not associated with biochemical recurrence-free survival. However, among patients with metastatic cancer, high B7-H3 expression was independently associated with high disease-specific mortality (multivariable hazard ratio [HR] = 2.72; p = 0.047) and overall mortality rates (multivariable HR = 2.04; p = 0.025).

CONCLUSIONS

Tumor B7-H3 expression in diagnostic biopsy specimens may be a useful biomarker for identifying highly aggressive metastatic prostate cancer. Given the potential utility of anti-B7-H3 immunotherapy, this information may aid in stratifying prostate cancer based on its responsiveness to B7-H3-targeted treatment.

B7 homologue 3 as a prognostic biomarker and potential therapeutic target in gastrointestinal tumors

The most common digestive system (DS) cancers, including tumors of the gastrointestinal tract (GIT) such as colorectal cancer (CRC), gastric cancer (GC) and esophageal cancer (EC) as well as tumors of DS accessory organs such as pancreatic and liver cancer, are responsible for more than one-third of all cancer-related deaths worldwide, despite the progress that has been achieved in anticancer therapy. Due to these limitations in treatment strategies, oncological research has taken outstanding steps towards a better understanding of cancer cell biological complexity and heterogeneity. These studies led to new molecular target-driven therapeutic approaches. Different in vivo and in vitro studies have revealed significant expression of B7 homologue 3 (B7-H3) among the most common cancers of the GIT, including CRC, GC, and EC, whereas B7-H3 expression in normal healthy tissue of these organs was shown to be absent or minimal. This molecule is able to influence the biological behavior of GIT tumors through the various immunological and nonimmunological molecular mechanisms, and some of them are shown to be the result of B7-H3-related induction of signal transduction pathways, such as Janus kinase 2/signal transducer and activator of transcription 3, phosphatidylinositol 3-kinase/protein kinase B, extracellular signal-regulated kinase, and nuclear factor-κB. B7-H3 exerts an important role in progression, metastasis and resistance to anticancer therapy in these tumors. In addition, the results of many studies suggest that B7-H3 stimulates immune evasion in GIT tumors by suppressing antitumor immune response. Accordingly, it was observed that experimental depletion or inhibition of B7-H3 in gastrointestinal cancers improved antitumor immune response, impaired tumor progression, invasion, angiogenesis, and metastasis and decreased resistance to anticancer therapy. Finally, the high expression of B7-H3 in most common cancers of the GIT was shown to be associated with poor prognosis. In this review, we summarize the established data from different GIT cancer-related studies and suggest that the B7-H3 molecule could be a promising prognostic biomarker and therapeutic target for anticancer immunotherapy in these tumors.

Expression of B7-H3 Correlates with PD-L1 and Poor Prognosis in Patients with Cervical Cancer

Purpose

The purpose of this study was to investigate B7 homolog 3 (B7-H3) expression patterns and define its associations with programmed cell-death ligand 1 (PD-L1), pathological features, and survival in patients with cervical cancer.

Patients and Methods

Immunohistochemical staining was used to investigate B7-H3 and PD-L1 expression in tissue microarrays from 552 patients with stage IB1 and IIA1 cervical cancer, including 406 with squamous cell carcinoma and 146 with endocervical adenocarcinoma.

Results

B7-H3 was expressed in the tumor cells (TCs) of 32.1% of the samples as well as in the stromal cells of 92.9% of the specimens. B7-H3 was co-expressed with PD-L1 in 21.0% of the samples, while only one or the other was expressed in 41.7% of the samples. B7-H3 expression in TCs was more frequent in squamous cell carcinoma, PD-L1-positive samples, and tissues from patients with lymph node metastasis; moreover, its expression was an independent predictor of shorter survival.

Conclusion

B7-H3 positivity in TCs is a promising prognostic biomarker, and targeting B7-H3 alone or in combination with PD-1/PD-L1 may be a potential immunotherapeutic strategy for patients with cervical cancer.

Perspectives on Immunotherapy of Metastatic Colorectal Cancer

Colorectal cancer, especially liver metastasis, is still a challenge worldwide. Traditional treatment such as surgery, chemotherapy and radiotherapy have been difficult to be further advanced. We need to develop new treatment methods to further improve the poor prognosis of these patients. The emergence of immunotherapy has brought light to mCRC patients, especially those with dMMR. Based on several large trials, some drugs (pembrolizumab, nivolumab) have been approved by US Food and Drug Administration to treat the patients diagnosed with dMMR tumors. However, immunotherapy has reached a bottleneck for other MSS tumors, with low response rate and poor PFS and OS. Therefore, more clinical trials are underway toward mCRC patients, especially those with MSS. This review is intended to summarize the existing clinical trials to illustrate the development of immunotherapy in mCRC patients, and to provide a new thinking for the direction and experimental design of immunotherapy in the future.

Characterization of immune infiltration in sarcomatoid hepatocellular carcinoma

Sarcomatoid hepatocellular carcinoma (sHCC) is a rare type of liver malignancy. Currently, the tumor immune features of sHCC are poorly understood. We recruited 31 patients with resected sHCC for whom tissue samples and complete clinicopathologic and follow-up data were available. To understand the immune infiltration of sHCC, immunohistochemical staining was performed on the resected sHCC samples to compare the expressions of programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), B7-H3, indoleamine 2,3-dioxygenase (IDO), lymphocyte-activation gene 3 (LAG-3), CD8, FOXP3, and CD68 in tumor and peritumoral tissues. Kaplan-Meier and Cox regression analyses were used to assess the predictive value of immune markers. Sarcomatoid components were characterized with significantly higher expression of PD-L1 and B7-H3 in tumor cells than in conventional HCC components, as well as in peritumoral tissue. Additionally, sarcomatoid components had a higher density of FOXP3⁺ and LAG-3⁺ cells and a lower density of CD8⁺ cells than conventional HCC components or peritumoral tissue. Higher expression of PD-L1 in tumor cells significantly correlated with higher densities of CD8⁺, PD-1⁺, and LAG-3⁺ cells. Increased tumor PD-L1 expression and decreased CD8⁺ T-cell density were associated with poor overall survival (OS) and disease-free survival (DFS) in patients of sHCC. These findings suggest further characterization on relative mechanism of sHCC immune infiltration may identify therapeutic targets for immunotherapy.

B7-H3 targeted antibody-based immunotherapy of malignant diseases

Introduction: Recent advances in immuno-oncology and bioengineering have rekindled the interest in monoclonal antibody (mAb)-based immunotherapies for malignancies. Crucial for their success is the identification of tumor antigens (TAs) that can serve as targets. B7-H3, a member of the B7 ligand family, represents such a TA. Although its exact functions and receptor(s) remain unclear, B7-H3 has predominantly a pro-tumorigenic effect mainly by suppressing the anti-tumor functions of T-cells.Areas covered: Initially we present a historical perspective on TA-specific antibodies for diagnosis and treatment of malignancies. Following a description of the TA requirements to be an attractive antibody-based immunotherapy target, we show that B7-H3 fulfills these criteria. We discuss its structure and functions. In a review and pooled analysis, we describe the limited B7-H3 expression in normal tissues and estimate B7-H3 expression frequency in tumors, tumor-associated vasculature and cancer initiating cells (CICs). Lastly, we discuss the association of B7-H3 expression in tumors with poor prognosis.Expert opinion: B7-H3 is an attractive target for mAb-based cancer immunotherapy. B7-H3-targeting strategies are expected to be highly effective and - importantly - safe. To fully exploit the diagnostic and therapeutic potential of B7-H3, its expression in pre-malignant lesions, serum, metastases, and CICs requires further investigation.

B7-H3 and PD-L1 Expression Are Prognostic Biomarkers in a Multi-racial Cohort of Patients with Colorectal Cancer

BACKGROUND

Immunotherapy has emerged as an effective and durable treatment modality for solid cancers. However, its use in colorectal cancer (CRC) is limited to deficient mismatch repair (dMMR) tumors. As such, assessing immune regulatory proteins from the B7-CD28 family, other than PD-1, PD-L1, and CTLA-4, is critical. This study aimed to evaluate the expression of novel protein regulators in a racially diverse population of patients with CRC.

METHODS

A tumor microarray was created for 214 samples from a multiracial patient population with metastatic CRC, and expression of HHLA2, B7-H3, PD-L1, CK7, CK20, and CDX2 was determined. The expression pattern was scored as 0 to 12, based on tumor tissue prevalence and the intensity. Clinical information was obtained by chart review and vital statistics from the National Death Index. Associations between low and high expression groups for each protein by race/ethnic groups were assessed, and Kaplan-Meier curves were plotted to evaluate association with survival.

RESULTS

The median age at diagnosis was 61 years, with a female predominance. The majority of the patients were diagnosed with de novo metastatic disease with left-sided, moderately differentiated tumors. There were no racial disparities in the expression of any protein. Overall, a high frequency of tumors had no expression of B7-H3 (62.5%) or PD-L1 (43.5%). Low expression of both PD-L1 and B7-H3 was a significant prognostic biomarker associated with better survival (median overall survival, 43.3 months vs. 24.6 months; P < .01).

CONCLUSION

In this multiracial tumor microarray of CRC samples, low PD-L1 and B7-H3 expression was associated with an improved prognosis. There was no significant variation among races with respect to the relevant CRC protein markers.

B7-H3 expression in upper tract urothelial carcinoma associates with adverse clinicopathological features and poor survival

B7-H3, a member of the B7 superfamily, is an immune checkpoint molecule. An association between B7-H3 expression and poor survival has been reported in many types of cancer. However, its prognostic value in patients with upper tract urothelial carcinoma (UTUC) has not yet been reported. The aim of this study was to examine the clinical significance of tumor B7-H3 expression in UTUC. B7-H3 positivity was observed in 36 of 271 cases (13 %) by immunohistochemistry and was significantly associated with several adverse clinicopathological features such as tumor grade, tumor stage, and lymph node metastasis. In addition, B7-H3 positivity was significantly associated with shorter metastasis-free survival and cancer-specific survival. We also found that B7-H3/programmed cell death ligand-1 (PD-L1) co-positivity was significantly associated with worse prognosis. These results suggest the utility of B7-H3 positivity and B7-H3/PD-L1 co-positivity as novel prognostic biomarkers in UTUC, and the potential usefulness of B7-H3 targeted therapy for patients with UTUC, the effect of which may be enhanced by combination with programmed cell death-1 /PD-L1 blockade.