Proportion Of Tumor-infiltrating Lymphocytes Research Articles

A novel [89Zr]-anti-PD-1-PET-CT to assess response to PD-1/PD-L1 blockade in lung cancer.

Harnessing the anti-tumor immune system response by targeting the program cell death protein (PD-1) and program cell death ligand protein (PD-L1) axis has been a major breakthrough in non-small cell lung cancer (NSCLC) therapy. Nonetheless, conventional imaging tools cannot accurately assess response in immunotherapy-treated patients. Using a lung cancer syngeneic mouse model responder to immunotherapy, we aimed to demonstrate that [89Zr]-anti-PD-1 immuno-PET is a safe and feasible imaging modality to assess the response to PD-1/PD-L1 blockade in NSCLC. A syngeneic mouse model responder to anti-PD-1 therapy was used. Tumor growth and response to PD-1 blockade were monitored by conventional 2-deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG) PET scans. Additionally, tumor lymphocyte infiltration was analyzed by the use of an [89Zr]-labeled anti-PD-1 antibody and measured as 89Zr tumor uptake. Conventional [18F]-FDG-PET scans failed to detect the antitumor activity exerted by anti-PD-1 therapy. However, [89Zr]-anti-PD-1 uptake was substantially higher in mice that responded to PD-1 blockade. The analysis of tumor-infiltrating immune cell populations and interleukins demonstrated an increased anti-tumor effect elicited by activation of effector immune cells in PD-1-responder mice. Interestingly, a positive correlation between [89Zr]-anti-PD-1 uptake and the proportion of tumor-infiltrating lymphocytes (TILs) was found (Cor = 0.8; p = 0.001). Our data may support the clinical implementation of immuno-PET as a promising novel imaging tool to predict and assess the response of PD-1/PD-L1 inhibitors in patients with NSCLC.

Abstract P2-21-04: The tumor immune microenvironment composition and prognostic value in breast cancer during pregnancy is dynamic during the gestation period

Abstract Introduction: Breast cancer (BC) during pregnancy (PrBC) is an uncommon malignancy characterized by a more aggressive clinical course compared to pregnancy-unrelated BC. Specific patterns of tumor-infiltrating lymphocytes (TILs) subpopulations have been observed in these patients, with significant prognostic roles. Previous studies demonstrated the varying histopathologic and prognostic profiles of PrBC by gestational age. However, the underlying immune landscape dynamics has never been investigated. Here, we sought to provide comprehensive insights into the association between gestational age at breast cancer diagnosis and tumor immune microenvironment (TIME) composition. Materials and Methods: A total of 110 PrBC were selected from our Institutional registry and categorized based on the trimester in which they were diagnosed. All cases were subjected to TILs profiling according to the International TILs Working Group recommendations. Immunohistochemistry for CD4, CD8, forkhead box P3 (FOXP3), and PD-L1 (clone 22C3) on a Dako Omnis platform was performed. Fisher’s and Chi-squared tests, multinomial logistic regression models, ROC curve, and survival analyses were performed. Results: The proportion of patients with high histologic grades incremented with the increase in gestational age (1st, n=24, 53%; 2nd, n=27, 69.2%; 3rd trimester, n=20, 87.0%; p=0.02). Neither breast cancer subtypes nor the hormone receptor (HR) and HER2 status changed significantly according to the pregnancy trimester. In HR+/HER2- subtype, the proportion of TILs+ tumors were higher in the early phases of pregnancy (1st, n=29, 100%; 2nd, n=17, 89.5%; 3rd trimester, n=9, 81.8%; p=0.04) imprinted by FOXP3 positivity where more FOXP3+ TILs were seen in the first months and decreased progressively (1st, n=10, 55.6%; 2nd, n=2, 11.8%; 3rd trimester, n=0, 0%; p< 0.01)). While in the triple negative breast cancer (TNBC) population, the proportion of PD-L1+ tumors (i.e. CPS>1) was significantly higher in the later stages of pregnancy (1st, n=2, 16.7%; 2nd, n=2, 18.2%; 3rd trimester, n=5, 71.4%; p=0.03). Patients who relapsed after a BC diagnosis during the 1st and 2nd trimesters lacked more frequently FOXP3+ and CD8+ cells, unlike those with no disease recurrence (n=21, 77.8% vs. n=17, 48.6%; p=0.02 and n=18, 66.7% vs. n=10, 28.6%; p< 0.01, respectively). Conclusions: TIME dynamics of PrBC are different according to the gestational age in both HR+ and TNBC PrBC. Our results suggest that immune tolerance events are likely to involve PrBC at later gestational age. Specific escape mechanisms (i.e., TILs and FOXP3 decrease in HR+ and PD-L1 expression in TNBC) might explain the aggressiveness of PrBC diagnosed during the later gestational age. Citation Format: Elham Sajjadi, Konstantinos Venetis, Mariia Ivanova, Marianna Noale, Concetta Blundo, Giovanna Scarfone, Eugenia Di Loreto, Stefano Ferrero, Stefania Maggi, Paolo Veronesi, Viviana Enrica Galimbreti, Giuseppe Viale, Fedro Alessandro A. Peccatori, Elena Guerini-Rocco, Nicola Fusco. The tumor immune microenvironment composition and prognostic value in breast cancer during pregnancy is dynamic during the gestation period [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-21-04.

Abstract 692: Patient-derived co-cultures of TRACERx lung cancer organoids and autologous T-cells reveal heterogeneity in immune evasion between cancer subclones

Abstract Introduction: Intra-tumor heterogeneity (ITH) is a major driver of treatment resistance. ITH also affects anti-tumor immunity, with immune cell infiltration, neo-antigen expression and T cell receptor (TCR) profiles differing between separate regions of an individual tumor. However, the extent to which separate tumor subclones differ in their capacity for immune evasion, the tumor-intrinsic mechanisms underlying any such heterogeneity, and its impact on cancer immunosurveillance remain largely unexplored. We have previously developed personalized models of anti-tumor immunity, based on co-cultures of cancer organoids and autologous T-cells. These co-culture systems can be used to evaluate the efficacy of cancer immunosurveillance at the level of an individual patient. Approach: Here, we leverage the multi-region TRACERx lung cancer evolution study to generate a patient-derived study platform that allows the evaluation of T-cell responses to individual cancer subclones. We generated libraries of >20 separate non-small cell lung cancer (NSCLC) organoid lines, based on isolating individual (clonal) organoids established from multiple spatially separated tumor regions. Each organoid subline was co-cultured with autologous tumor infiltrating lymphocytes (TIL) to evaluate how they differ in their capacity to elicit a T-cell response. Results: Our data reveal heterogeneity between individual clonal organoid sublines in their capacity to stimulate TIL. The proportion of TIL being activated by a particular subclone, as measured by 4-1BB (CD137) expression, ranged from 5 to 42%. These differences could not be explained by differences in MHC class I or PD-L1 expression. We are currently using DNA, RNA and TCR sequencing to characterize ‘immune evading’ and ‘non-immune evading’ sublines. Data will be updated on emerging subclonal immune evasion mechanisms inferred through DNA/RNA/TCR sequencing. Conclusion: Individual cancer subclones show differences in the degree of immune evasion. This patient-derived study platform allows moving beyond descriptive analyses of the heterogeneity of anti-tumor immunity, allowing fine-grained functional studies of how ITH affects cancer immunosurveillance. Citation Format: Krijn K. Dijkstra, Roberto Vendramin, Robert E. Hynds, David R. Pearce, Despoina Karagianni, Felipe Gálvez-Cancino, Oriol Pich, Mark S. Hill, Vittorio Barbè, Andrew Rowan, Selvaraju Veeriah, Cristina Naceur-Lombardelli, Antonia Toncheva, Supreet Bola, Mariam Jamal-Hanjani, Crispin Hiley, Kevin Litchfield, James Reading, Sergio A. Quezada, Charles Swanton, TRACERx consortium. Patient-derived co-cultures of TRACERx lung cancer organoids and autologous T-cells reveal heterogeneity in immune evasion between cancer subclones [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 692.

MIF improves immune microenvironment of Lewis lung cancer brain metastases after radiotherapy via reducing M2 macrophages.

e21026 Background: Our previous studies showed that inhibition of MIF/CD74 signaling pathway can promote the transformation of intracranial macrophages from M2 to M1 type after radiotherapy in brain metastases(BMs). It is reported that M2 macrophages are the main components of tumor immunosuppression microenvironment, and the surface marker, ARG-1, can decompose the Arginine which is essential in the growth and development of T cells. Therefore, this paper will focus on the mechanism of MIF regulating tumor infiltrating lymphocytes (TILs) by inducing macrophage phenotype transformation. Methods: MIF-Knockdown in Lewis cells were constructed by lentiviral shRNA interference technique. The expression levels of MIF in Lewis and iNOS (M1 type marker), Arg-1 (M2 type marker) in BV2 cells were detected by WB. The RNA expression levels of M1 and M2 tags were detected by qPCR. The expression of iNOS, Arg-1 and Iba-1 in lung cancer BMs model mice was detected by IF. The content of arginine in tumor tissue and clinical patient specimens were detected by Arginine kit. The proportion of TILs in vivo was measured by flow cytometry. BMs tumor growth in mice was observed by Small Animals Imaging Technology. Results: In animal experiments, WB、PCR and IF results showed that MIF knockdown (sh-MIF) combined with whole brain irradiation(IR) can raise the expression of iNOS, while the Arg-1 lessend, suggesting that downregulation of MIF can promote M1 phenotype and reduce M2 phenotype. Flow cytometry results showed that sh-MIF combined with IR increased the proportion of CD8+T/CD4+T cells . After clearance of macrophage, Flow cytometry showed no difference between the sh-MIF group and the control group (NC). Small Animals Imaging results also showed that the inhibition of tumor growth by sh-MIF was less significant than macrophages presence. It is indicated that down-regulation of MIF expression combined with irradiation promote T cell infiltration and inhibit tumor may be mediated by macrophages. Arginine kit results showed that the content of arginine increased after IR or sh-MIF, while it increased overall after macrophage clearance, but the difference between each groups was not significant, suggesting that IR or sh-MIF could increase the content of arginine by reducing M2-type macrophages. Flow cytometry and animals imaging results showed that the CD8+/CD4+TILs ratio was increased and tumor growth was inhibited after the addition of exogenous arginine. In clinical samples, the content of arginine in CSF decreased after radiotherapy, which suggests that arginine supplementation has the potential to improve the effect of radiotherapy. Conclusions: Inhibitory MIF expression can reduce the expression of Arg-1 from M2 type macrophages in BMs, thus raise the content of arginine, promote the infiltration of lymphocytes, improve the immune microenvironment, achieve radiotherapy sensitization finally.

Chemokine CCL17 Affects Local Immune Infiltration Characteristics and Early Prognosis Value of Lung Adenocarcinoma.

CCL17 is an important chemokine that plays a vital immunomodulatory role in the tumor microenvironment (TME). Analysis of lung adenocarcinoma (LUAD) data in Kaplan–Meier plotter databases found that the overall survival of patients in the CCL17 high-expression group was higher than that of the low-expression group, especially for patients with early (stages I and II) LUAD, which has a more positive prognostic value. Expression of CCL17 in LUAD was positively correlated with the proportion of tumor-infiltrating lymphocytes, immunostimulators, and major histocompatibility complexes using the TISIDB databases. Based on the RNA-seq and clinical data of 491 LUAD patients obtained from the TCGA database, 1,455 differential genes were found between the CCL17 high- and low-expression groups. Using WGCNA analysis confirmed that the expression of differential genes in the blue module is negatively correlated with poor survival and clinical stages of LUAD patients, and CCL17 and CCR4 genes belong to the hub genes in the blue module. Further analysis by the ESTIMATE and CIBERSORT algorithm found that the naive B cells and CD8+ T cells in the CCL17 high-expression group have a higher distribution ratio in the early LUAD patients, and the high immune score has a positive relationship with the overall survival rate. Using somatic mutation data of TCGA-LUAD, we found that 1) the tumor mutation burden values of the CCL17 high-expression group were significantly lower than those of the CCL17 low-expression group and 2) the expression levels of CCL17 and the tumor mutation burden values were negatively correlated. Transwell chemotaxis and cytotoxicity assays confirmed that CCL17 contributes to the migration of CCR4-positive lymphocytes into the H1993 LUAD TME and enhances the specific lysis of LUAD cells. In summary, high expression of CCL17 in the LUAD TME promotes local immune cell infiltration and antitumor immune response, which may contribute to the better survival and prognosis of patients with early LUAD.

Abstract OT-31-01: A phase II study to evaluate the efficacy and safety of pembrolizumab plus carboplatin in BRCA-related metastatic breast cancer: PEMBRACA trial

Abstract Background Considering the high proportion of tumor-infiltrating lymphocytes (TILs) in BRCA-related breast cancer, we expect that PD-1 pathway is highly expressed and PD-1 antagonist pembrolizumab could provide clinical activity in this kind of tumor. Furthermore, BRCA-related breast cancers are known to be more sensitive to platinum-derived drugs. Thus the association between Pembrolizumab and Carboplatin in metastatic BRCA-related breast cancer seems to be active in this setting of patients. This study will evaluate the safety and the efficacy of Pembrolizumab associated with Carboplatin in BRCA mutated or with unknown mutations metastatic breast cancer patients. Study and Statistical DesignThis is a national multicenter two-stage single arm phase II study, enrolling BRCA mutated or with unknown mutations metastatic breast cancer patients. The sample size has been estimated by using the two-stage Simon’s design. In the first stage, 20 subjects will be enrolled. If, after first stage ≤11 responses (r1) will be observed, accrual will terminate and the experimental regimen will be rejected. Otherwise if 12 or more responses will be seen then the accrual will continue to the second stage of an additional 33 subjects (total, 53 subjects). At the second stage if 33 or less responses out of 53 subjects will be observed the treatment will be rejected. With the null hypothesis (p0) being equal 0.55 with a type I (alfa) error of 0.10 (10%) and a type II (beta) error of 0.20 (power=80%) and the alternative hypothesis (p1) is 0.70, (response rate 70%), we expect to reach an overall response rate (ORR) ≥ 70% by the combination of Pembrolizumab plus Carboplatin. We also expect to reach a median Time to Progression (TTP) and Overall Survival (OS) of five and fifteen months respectively. The Disease Control Rate (DCR) will be expected as ≥ 80% by the combination of Pembrolizumab plus Carboplatin Study TreatmentCarboplatin at area under the time-concentration curve 6 (AUC 6) intravenously once every 3 weeks in combination with Pembrolizumab 200 mg intravenously every 3 weeks will be administered for six courses and then only Pembrolizumab alone will continue until occurrence of unacceptable toxicities or disease progression. Eligibility CriteriaIn order to be eligible for participation in this trial, the subject, aged ≥ 18 years, must have metastatic confirmed breast cancer, with a disease progression by radiological techniques within 12 months prior to signing informed consent, and a documented mutation in BRCA1 or BRCA2 genes that is predicted to be deleterious or suspected deleterious or with unknown significance. The subject must have measurable disease based on RECIST 1.1 and have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) Performance Scale. Prior chemotherapy with anthracyclines and taxanes has to be administered in neoadjuvant or adjuvant setting. In case of luminal tumors hormonal treatments for advanced disease can be administered before. The life expectancy must be greater than 3 months and the subject must demonstrate adequate organ function by screening labs performed within 10 days of treatment initiation. Objectives and HypothesisThe primary end-point will be the ORR, evaluated according to RECIST criteria. Secondary objectives will be the TTP, the duration of response (DOR ), the DCR, and the OS. The safety of the combination will be evaluated according to the worst toxicity grade reported throughout the whole treatment period.The Exploratory Objective will be the evaluation of ORR, TTP, DOR, and DCR based on irRECIST. Biological parameters of CD8/TILs and PD-L1 will be considered in the metastatic biopsy. Target AccrualThe first subject was enrolled in January 2019 and recruitment is ongoing. Enrollment of the first 20 subjects is expected to complete in Q2 2021. Citation Format: Laura Cortesi, Marta Venturelli, Federica Caggia, Luigi Marcheselli, Annita Gozzi, Alberto Zambelli, Valentina Guarneri, Antonino Musolino, Elena Fiorio, Giancarlo Bisagni, Andrea Rocca, Valentina Arcangeli, Elisabetta De Matteis, Sergio Rizzo, Andrea Michelotti. A phase II study to evaluate the efficacy and safety of pembrolizumab plus carboplatin in BRCA-related metastatic breast cancer: PEMBRACA trial [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-31-01.

Relationship between PD-L1 Expression and Tumor-Infiltrating Lymphocytes in Canine Mammary Tumor

Background: Studies pointed out that the tumor-infiltrating lymphocytes (TILs) have considerable importance in canine mammary tumor (CMT). On the other hand, cancer cells sometimes find ways to use immune checkpoint proteins as a shield to avoid being identified and attacked by the immune system as programmed death 1 ligand 1 (PD-L1). In this study, it was investigated the relationship between PD-L1 expression, stromal tumor-infiltrating lymphocytes (TILs) in canine mammary tumor (CMT), and the association with clinical and pathological characteristics of the tumors.Materials, Methods & Results: PD-L1 expression and TILs were assessed in 23 female dogs with CMT. The tumors were grouped into simple carcinoma (CA, n = 8) and complex carcinoma (CC, n = 15). Stromal TILs were assessed using two thresholds as TILs-Low representing < 50% of infiltrate within stromal area and TILs-High representing ≥ 50% of stromal area. Clinicopathological data of CMT was characterized according to key parameters, as well as survival rates. TILs evaluation within tumor stroma revealed that 65.2% (n = 15) of tumors had TILs-Low. PD-L1 expression and stromal TILs were significantly associated (P = 0.009). PD-L1 expression was observed in 39% (n = 9) of all tumors of which 17.4% (n = 4) were from CA group and 21.7% (n = 5) were from CC group. PD-L1 expression within TILs was observed in 39% (n = 9) of the tumors. PD-L1 in malignant epithelium was present in all lymph node metastasis (n = 5). PD-L1 was associated with involvement of regional lymph nodes (P = 0.034). Survival curves demonstrated TILs-Low had higher (P = 0.010) overall survival (OS) compared with TILs-High, and PD-L1+ and PD-L1– (P = 0.06) did not differed. The clinicopathological variables significantly correlated with OS by univariate analysis were the histological grade (P = 0.009), lymph node involvement (P = 0.004), stromal TILs (P = 0.016), and PD-L1+/TILs-High vs. PD-L1–/TILs-Low (P = 0.010). Multivariate analysis revealed that group of tumors with grade II-III was independent and negative prognostic factors for OS.Discussion: In this study, PD-L1 was differently expressed according to the histologic subtypes of TMC. Currently, has been showed the presence of PD-L1 in several canine cancer. Nevertheless, only a few studies have described PD-L1 protein expression in dog tumors and showed PD-L1 was constitutively expressed on canine tumor cell lines, although the levels of basal expression were very variable. This expression can be modulated by IFN-γ exposure. In the present study, it was found a strong PD-L1 expression on TILs. The increase in PD-L1 cell surface expression by tumor cells can lead to decreased T-cell proliferation and increased apoptosis. In human breast cancer (BC) the PD-L1 expression was expressed in TILs and tumor epithelium. It has been reported the association of stromal TILs and PD-L1 expression with aggressive types and stages of BC. In this study, it was detected PD-L1 expression in malignant epithelium in all lymph node metastasis. PD-L1 overexpression was significantly associated with a series of clinicopathological parameters. It was demonstrated that PD-L1+/TILs-High had higher risk of overall survival (OS) than another group of interaction. High PD-L1 expression may be a prognostic indicator for reduced OS, while tumor PD-L1+ was associated with poorer disease-free survival. The presence of TILs has shown to be potentially predictive and a prognostic factor in BC subtypes. In CMT, it has been reported that a high proportion of TILs was correlated to several malignancy characteristics. In relation to PD-L1, further research is necessary to clarify this immune checkpoint as a potential therapeutic target and its application in clinical practice in CMT.

Treatment with an immature dendritic cell-targeting vaccine supplemented with IFN-α and an inhibitor of DNA methylation markedly enhances survival in a murine melanoma model.

The chemokine MIP-3α (CCL20) binds to CCR6 on immature dendritic cells. DNA vaccines fusing MIP-3α to melanoma-associated antigens have shown improved efficacy and immunogenicity in the B16F10 mouse melanoma model. Here, we report that the combination of type-I interferon therapy (IFNα) with 5-Aza-2'-deoxycitidine (5Aza) profoundly enhanced the therapeutic efficacy of a MIP-3α-Gp100-Trp2 DNA vaccine. Beginning on day 5 post-transplantation of B16F10 melanoma, vaccine was administered intramuscularly (i.m.) by electroporation. CpG adjuvant was given 2days later. 5Aza was given intraperitoneally at 1mg/kg and IFNα therapy either intratumorally or i.m. as noted. Tumor sizes, tumor growth, and mouse survival were assessed. Tumor lysate gene expression levels and tumor-infiltrating lymphocytes (TILs) were assessed by qRT-PCR and flow cytometry, respectively. Adding IFNα and 5Aza treatments to mice vaccinated with MIP-3α-Gp100-Trp2 leads to reduced tumor burden and increased median survival (39% over vaccine and 95% over controls). Tumor lysate expression of CCL19 and CCR7 were upregulated ten and fivefold over vaccine, respectively. Vaccine-specific and overall CD8+ TILs were increased over vaccine (sevenfold and fourfold, respectively), as well as the proportion of TILs that were CD8+ (twofold). Efficient targeting of antigen to immature dendritic cells with a chemokine-fusion vaccine offers an alternative to classic and dendritic cell vaccines. Combining this approach with IFNα and 5Aza treatment significantly improved vaccine efficacy. This improved efficacy correlated with changes in chemokine gene expression and CD8+ TIL infiltration and was dependent on the presence of all therapeutic components.

Abstract P5-07-07: The immune microenvironment of ductal carcinoma in situ of the breast

Abstract Background: The importance of tumor-infiltrating lymphocytes (TIL) in invasive breast carcinoma for tumor development and therapeutic response is widely accepted. However, the immune microenvironment of breast ductal carcinoma in situ (DCIS) has not been fully elucidated. Evasion of immune surveillance is a necessary step in tumor evolution. In DCIS, the tumor cells are relatively protected from the immune system due to an myoepithelial cell layer and basement membrane, and intraductal immune cells are rarely detected. In contrast, in invasive disease, cancer cells and immune cells are often intermingled. Thus, understanding the immune microenviroment of in situ to invasive carcinoma transition might be particularly important to identify novel targets for early stage of tumor invasion. Aims: The aim of this study is to evaluate the clinical importance of TILs in DCIS. Methods: TILs were assessed in 133 DCIS samples with or without microinvasive disease according to the proposed method from the International Immuno-Oncology Working Group on Breast Cancer. In addition, the relationship between TILs in DCIS and clinicopathological features was evaluated. Results: TILs are present in most DCIS in varying levels. The median proportion of TILs in DCIS was 14%. Only a minority of DCIS showed >50% TILs, which represented only 12.8% of all cases. High TILs in DCIS was significantly associated with comedo necrosis (p<0.0001), high nuclear grade (p=0.0030), ER negativity (p<0.0001), PR negativity (p<0.0001), HER2 positivity (p=0.0030). Triple negative DCIS and HER2 positive DCIS had significantly higher level of TILs (p=0.0008). No correlation was demonstrated between TILs and recurrence risk. Conclusions: High TILs in DCIS was significantly associated with adverse histopathologic features. Further characterization of immune environment of DCIS may be essential for immunotherapy and breast cancer prevention. Citation Format: Yamashita N, Hisamatsu Y, Shigechi T, Tokunaga E, Saeki H, Oki E, Maehara Y. The immune microenvironment of ductal carcinoma in situ of the breast [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-07-07.

Expression of PD-L1 on Immune Cells Shows Better Prognosis in Laryngeal, Oropharygeal, and Hypopharyngeal Cancer.

Despite great enthusiasm towards immunotherapy, reliable biomarkers are still lacking. The importance of subsets based on human papillomavirus (HPV) status is supported by a growing body of evidence. However, role of other possible subgroups such as anatomic localization of primary tumor remains controversial. Our objective was to investigate immune cell infiltrate and checkpoint inhibitor proteins in above-mentioned head and neck cancer subsets. Archival tumor samples of 106 laryngeal, oropharyngeal, and hypopharyngeal cancer patients were stained with PD-L1, PD-L2, PD-1, and CTLA-4 antibodies. Proportion of tumor-infiltrating lymphocytes was assessed as well. In HPV-negative tumors, PD-L1 immune cell positivity was associated with better disease-specific survival. PD-L1 expression on immune cells correlated with improved disease-specific survival in laryngeal tumors. Furthermore, PD-L1 immune cell positivity correlated with CTLA-4 expression on immune cells and it was accompanied by high tumor-infiltrating lymphocyte rate. PD-L1 expression on tumor cells and PD-1 status showed strong correlation in all patients and in oropharyngeal and laryngeal localization, but not in hypopharynx. HPV-negative oropharyngeal cancers showed negative PD-L1 status on tumor cells. CTLA-4 positivity was observed in 49.5% and 20.6% on immune cells and on tumor cells, respectively. We concluded that PD-L1 expression on immune cells indicates better prognosis in laryngeal squamous cell carcinoma and in HPV-negative head and neck squamous cell carcinoma. We have not found any essential differences between anatomic subgroups. A possibly distinct role of hypopharyngeal localization regarding immune activity requires further clarification.

Abstract 1013: Analyzing infiltrating B cell populations in the tumor microenvironment using single cell transcriptomics

Abstract Understanding the complex interactions between malignant, stromal and infiltrating lymphocyte cell types within the tumor microenvironment is a critical component of personalized cancer treatments. We describe an approach that couples single-cell transcriptional profiling of tumors with high-resolution receptor profiling of tumor infiltrating lymphocytes (TILs). Using a fully integrated, droplet-based system for 5' single cell RNA sequencing (scRNA-seq), we simultaneously profiled the transcriptome and immune repertoire of the same cells from a primary colorectal cancer (CRC) tumor and a primary non-small cell lung cancer (NSCLC) tumor. Each tumor varied in type and proportion of its cellular components, noticeably in the proportion of TILs. The tumor cells in the CRC were mostly epithelial in nature, with the TILs comprising 21% of the total cells sequenced. This lymphocyte population consisted of both T (5% CD4+, 3% CD8+) and, interestingly, B cells (5% CD19+), with a number of plasma B cells (IGH high, CD138+) also identified. The NSCLC tumor had a high immune cell infiltrate, with lymphocytes comprising 43% of cells (19% T, 23% B, and 5% plasma B cells) indicating a robust adaptive immune response. To examine these cells further, CD45+ cells were subject to scRNA-seq. When compared to the unenriched sample, the enriched cell population had a similar B to T cell ratio with a reduction in the proportion of plasma B cells, likely due to exclusion of mature plasma B cells by the sort (47% T (44% CD4+, 29% CD8+), 42% B, and 2% plasma B cells). To fully characterize the B cell infiltrate we applied targeted 5' scRNA-seq to obtain full length, paired, B cell receptor heavy and light chain sequences. Despite the presence of plasma B cells in the CRC tumor, limited clonal expansion was observed. In the NSCLC tumor, clonal expansion of B cells was observed in the unenriched tumor sample but these clonotypes were not present in the CD45+ population, suggesting the clonally expanded cells are in the mature plasma B cell population. We also applied a targeted scRNA-seq approach to obtain full length paired T cell receptor alpha and beta sequences, however, no clear T cell expansion was observed in either sample. These findings emphasize the importance of examining receptor sequences rather than relying on the presence of B or T cells alone to determine if a robust immune response is being mounted. The presence of tumor-infiltrating B lymphocytes has been linked to a favorable clinical outcome in some types of cancers. Identification of these cells, their subsets and high resolution profiling of their receptor sequences using scRNA-seq allows a novel insight into the adaptive immune response in tumors. This technology will allow better characterization of tumor heterogeneity and the adaptive immune response to the tumor microenvironment and will serve as a foundation for future research into tumor immunology and immunotherapy. Citation Format: Sarah E. Taylor, Stephane Boutet, Valeria Giangarrá, Grace X. Zheng, Alvaro M. Barrio, Luz Montesclaros, Josephine Lee, Samuel Marrs, Kevin J. Wu, Paul Ryvkin, Tarjei Mikkelsen, Deanna M. Church. Analyzing infiltrating B cell populations in the tumor microenvironment using single cell transcriptomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1013.

PD-L1 expression as a predictive biomarker for cytokine-induced killer cell immunotherapy in patients with hepatocellular carcinoma

ABSTRACTCytokine-induced killer (CIK) cell immunotherapy represents an effective treatment strategy for treating hepatocellular carcinoma (HCC). However, the therapeutic benefits of CIK cell treatment can be influenced by differences in complex immune microenvironment between patients. Herein, we investigated the relationship between PD-L1 expression and survival benefits of CIK cell immunotherapy in HCC patients. This retrospective study included 448 HCC patients: 217 cases underwent hepatectomy alone; 231 cases received hepatectomy and post-operative CIK cell transfusion. Immunohistochemistry was used to measure PD-L1 expression in tumor tissue sections from all patients. Meanwhile, flow cytometry was performed to explore the relationship between PD-L1 expression and localized inflammatory response in HCC microenvironment. We found a significantly improved prognosis in CIK treatment group compared with surgery alone group. In the CIK treatment group, higher PD-L1 expression was observed in patients who exhibited long-term survival benefit. Survival analysis showed patients with ≥5% PD-L1 expression had better overall survival (OS) and recurrence-free survival (RFS) than patients with 1–5% or <1% PD-L1 expression, particularly in the subgroup with high hepatitis B viral load. By contrast, PD-L1 expression did not show direct impact on the survival of patients in surgery alone group. Additionally, PD-L1 expression was found to be highly associated with hepatitis B viral load and the proportion of tumor-infiltrating lymphocytes in HCC patients. In conclusions, our study indicates that PD-L1 expression may reflect the presence of endogenous host immune response to tumor and serve as a biomarker for predicting survival benefits from adjuvant CIK cell immunotherapy in HCC patients.

Abstract 2349: EGFR is transferred from triple negative breast cancer cells to immune cells via trogocytosis and expression of EGFR on immune cells is associated with high tumor grade of triple negative breast cancer patients

Abstract We and others previously reported that HER2 was transferred from HER2 overexpressing breast cancer cells to CD14+ monocytes via trastuzumab dependent trogocytosis. In the current study, we report that EGFR of MDA-MB-231 (triple negative human breast cancer cell line) is also transferred to immune cells via trogocytosis and those immune cells express EGFR on the cell surface without antibody administration. Interestingly, the EGFR-trogocytosed MDA-MB-231 cells reduced the expression of EGFR and changed their morphology to the spindle shape (well known as mesenchymal transition) and acquired greater cell motility. These cancer cell properties are representative as higher malignant potentials in breast cancer patients. Thus, we hypothesized that EGFR expression on tumor infiltrating lymphocytes (TILs), which probably is caused via EGFR trogocytosis by TILs, is correlated with higher tumor grade. We evaluated the EGFR expression of TILs in 36 triple negative breast cancer specimens and found the correlation between EGFR expression status on TILs and higher tumor grade (P = 0.02). These findings may explain the reason why triple negative breast cancer with greater proportion of TILs exhibit higher tumor grade and poor prognosis. Citation Format: Eiji Suzuki, Ayane Yamaguchi, Tatsuki R. Kataoka, Masahiro Hirata, Kosuke Kawaguchi, Mariko Nishie, Masakazu Toi. EGFR is transferred from triple negative breast cancer cells to immune cells via trogocytosis and expression of EGFR on immune cells is associated with high tumor grade of triple negative breast cancer patients. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2349. doi:10.1158/1538-7445.AM2015-2349

Depletion of CD4+CD25+ regulatory T cells enhances interleukin‐2‐induced antitumor immunity in a mouse model of colon adenocarcinoma

Interleukin 2 (IL)-2 induces antitumor immunity and clinical responses in melanoma and renal cell carcinoma. However, IL-2 also increases the number of CD4(+)CD25(+) regulatory T (Treg) cells that suppress antitumor immune responses. The aim of the present study was to elucidate the effect of depletion of Treg cells on IL-2-induced antitumor immunity. IL-2-transfected mouse colon adenocarcinoma (MC38/IL-2) cells were implanted subcutaneously or intrahepatically into male C57BL/6 mice, and tumor growth and the proportion of tumor-infiltrating lymphocytes with Treg-cell depletion in response to treatment with anti-CD25 monoclonal antibody (PC61) were determined. In mice treated with phosphate-buffered saline, 40-60% of MC38/IL-2 tumors were rejected. In contrast, all MC38/IL-2 tumors were rejected in mice treated with PC61. The number of tumor-infiltrating CD8(+) T cells in mice treated with PC61 was approximately twice that in mice treated with PBS. The numbers of tumor-infiltrating CD4(+) and natural killer cells were also increased significantly. To test the antimetastatic effects of IL-2 treatment in combination with Treg-cell depletion, human recombinant IL-2 (rIL-2) and PC61 were administered to mice implanted with MC38/mock cells in the spleen, and hepatic metastasis was investigated. The average liver weight in mice treated with rIL-2 plus PC61 was 1.04 +/- 0.03 g, less than that in mice treated with rIL-2 (2.04 +/- 0.51 g) or PC61 alone (1.81 +/- 0.38 g). We conclude that IL-2-induced antitumor immunity is enhanced by Treg-cell depletion and is due to expansion of the tumor-infiltrating cytotoxic CD8(+) T-cell population.

Effect of tumor infiltrating lymphocytes on the expression of MHC molecules in canine transmissible venereal tumor cells

Canine transmissible venereal tumor (CTVT) can be allo-transplanted across major histocompatibility complex barriers. The expression of MHC molecules is usually low in the progression (P) stage and then greatly increases during tumor regression (R). We investigated the effects of tumor infiltrating lymphocytes (TIL) on the expression of MHC molecules of CTVT cells. Isolated, viable CTVT cells were inoculated at each of 12 sites (1×10 8 CTVT cells per site) on the back of six, mixed-breed dogs. Tumor masses were collected every 2–3 weeks and prepared for histopathologic, immunocytochemistry, flow cytometry and immunoblotting studies. The level of MHC expression on tumor cells from different stages of growth was measured. Initially, expression of MHC I and II molecules in P phase CTVT was low. Twelve weeks post-inoculation (PI), expression increased dramatically and it continued to increase during R phase. Tumor growth slowed after 12 weeks PI and tumors entered R phase around 17 weeks PI. We hypothesize that CTVT evades host immunosurveillance and grows progressively for 12 weeks, when it becomes vulnerable and subject to the host’s anti-tumor immune responses. We further demonstrated that R phase, but not P phase, TIL were closely associated with the over-expression of MHC I and II molecules by CTVT cells. The number and proportion of TIL were higher in R phase tumors. Supernatants, from R phase co-cultures (CTVT+TIL) and TIL only, promoted MHC I and II expression on P phase CTVT cells. After culturing alone for 1 month, expression of MHC classes I and II molecules in R phase CTVT cells decreased to the level of P phase CTVT cells. However, the above-mentioned supernatants restored their expression of MHC I and II molecules. In contrast, supernatants from P phase TIL or CTVT cells increased expression slightly or had no effect. Therefore, TIL, not CTVT cells, produce the effective substance (s) to promote the expression of MHC molecules by the tumor cells. Heat treated supernatant was unable to promote the expression of MHC I and II molecules by CTVT cells. In conclusion, TIL isolated from R phase CTVT secreted a heat-sensitive, soluble substance(s) that triggered over-expression of MHC I and II after 12 weeks PI. This caused the tumor to enter R phase and helped stop CTVT growth. Our findings will facilitate the understanding and further investigation of the mechanisms that initiate host immune surveillance against tumors.

Expression and activity of P-glycoprotein in transplantable hamster melanomas

In the study described here we investigated the possibility of an association between the aggressiveness of melanoma and multidrug resistance phenotype by analyzing the expression and activity of P-glycoprotein (Pgp) in two genetically related transplantable hamster melanomas--a melanotic (Ma) and an amelanotic (Ab) form --which differed in aggressiveness and metastatic potential. Flow cytometric analysis of Pgp activity (using a verapamil-sensitive rhodamine R123 exclusion test) as well as Western blotting of cellular lysates showed its preferential (although not very marked) expression in the Ab melanoma cells. The Ab melanoma cells also exhibited a higher proportion of tumor-infiltrating lymphocytes (TIL), mostly of T cell phenotype, that may have reflected a higher immunogenicity of the tumor. In conclusion, Pgp activity appeared to be associated with less-differentiated more aggressively metastasizing melanoma (the Ab variant) although its role in maintaining this phenotype remains to be established.