Predictive factors of the tumor immunological microenvironment for long‐term follow‐up in early stage breast cancer

The aim of this research was to investigate the correlation of immunologic factors in the tumor environment of breast cancer, using immunohistological staining to evaluate the expression of programmed death 1/programmed death ligand 1 (PD‐1/PD‐L1), phosphatase and tensin homolog (PTEN), tumor infiltrating lymphocytes (TILs), and macrophages, and to analyze the association between the immunologic factors and clinical outcome for patients with early stage breast cancer (EBC). A total of 97 EBC patients who underwent standard surgery were investigated. Expression of PD‐1/PD‐L1 and PTEN and the density of CD3⁺ TILs, CD8⁺ TILs, and CD163⁺ macrophages were evaluated by immunohistochemical analysis. The association between the immunologic factors and clinical outcome was statistically analyzed. The density of CD3⁺ TILs, CD8⁺ TILs, and CD163⁺ macrophages and non‐expression of PTEN was significantly higher in cases of triple negative breast cancer. CD8⁺ TIL density and CD8⁺/PD‐L1⁺ expression were predictive factors for disease‐free survival and overall survival (OS). Human epidermal growth factor 2 (HER2)‐positive patients with PTEN expression and luminal/HER2‐negative patients without PD‐L1 expression had significantly longer OS compared to patients without PTEN expression (P = 0.049) and with PD‐L1 expression (P = 0.036), respectively. Furthermore, patients with PD‐L1⁺/CD8⁺ expression had worse median progression‐free survival (P = 0.022) and median OS (P = 0.037) compared with patients without PD‐L1⁺/CD8⁺ expression. The CD3⁺ TILs, CD8⁺ TILs, and CD163⁺ macrophages were shown to infiltrate the tumor area of EBC. In particular, triple negative breast cancer had a higher rate of TIL infiltration within the tumor environment. Expression of PTEN and lack of PD‐L1 expression were associated with favorable survival in HER2‐positive and luminal/HER2‐negative EBC patients, respectively. The PD‐L1 expression combined with CD8⁺ density was significantly associated with an aggressive clinical outcome.     

PD‐L1 expression is low in large B‐cell lymphoma with MYC or double‐hit translocation

In large B‐cell lymphoma (LBCL), MYC translocation and MYC/BCL2 or MYC/BCL6 double hit (DH) are associated with poor prognosis, and there is an unmet need for novel treatment targets in this patient group. Treatments targeting the PD‐L1/PD‐1 pathway are still poorly elucidated in LBCL. PD‐L1 expression might predict response to treatment targeting the PD‐L1/PD‐1 pathway. We therefore investigated the relationship between PD‐L1 protein and mRNA expression levels and MYC and DH translocation in LBCL. We detected MYC, BCL2, and BCL6 translocation by fluorescent in situ hybridization in tissue samples from 130 patients randomly selected from two cohorts of patients with LBCL: 49 patients with MYC translocation of whom 36 had DH and 81 without MYC translocation. PD‐L1 protein expression was detected by immunohistochemistry (IHC) in tissue samples from 77 patients and PD‐L1 mRNA expression by next‐generation RNA sequencing (NGS) in another 77 patients. Twenty‐four patients overlapped, ie, were analysed with both IHC and NGS. Nonparametric tests were performed to evaluate intergroup differences. PD‐L1 protein expression level was significantly lower in patients with MYC (n = 42, median = 3.3%, interquartile range [IQR] 0.0‐10.8) or DH translocations (n = 31, median = 3.3%, IQR 0.0‐10.0) compared with patients with no MYC (n = 35, median = 16.7%, IQR 3.3‐30.0) or no DH translocations (n = 46, 13.3%, IQR 2.5‐30.0), P = .004 and P ≤ .001, respectively. PD‐L1 mRNA expression was also significantly lower in patients with MYC or DH translocations, P = .001 and P = .006, respectively. Higher PD‐L1 protein and mRNA expression levels were associated with non–germinal centre (GC) type compared with germinal centre B‐cell (GCB)‐type diffuse LBCL (DLBCL), P = .004 and P = .002, respectively. In conclusion, we report an association between low PD‐L1 expression and MYC and DH translocation in patients with LBCL. Our findings may indicate that patients with MYC or DH translocation may benefit less from treatment with PD‐L1/PD‐1‐inhibitors compared with patients without these translocations. This should be evaluated in larger, prospective, consecutive trials.     

Upregulation of programmed cell death ligand 1 promotes resistance response in non‐small‐cell lung cancer patients treated with neo‐adjuvant chemotherapy

To assess the association of the programmed cell death ligand 1 (PD‐L1) with cisplatin‐based neo‐adjuvant chemotherapy (NAC) response, we investigated the level of PD‐L1 and found increased PD‐L1 expression in chemo‐resistant tumors compared with chemo‐sensitive tumors according to RNA‐Seq analysis. In a cohort of 92 patients with NAC, the positive staining of PD‐L1 was correlated with TNM stage, lower sensitive‐response rates and shorter overall survival rates. In another 30 paired tumor specimens pre‐ and post‐chemotherapy, the patients with high PD‐L1 expression post‐chemotherapy had a worse outcome and higher stable disease rate. CD8⁺ tumor‐infiltrating lymphocytes were found to be related to chemosensitive response and better prognosis and negative PD‐L1 expression. Furthermore, in two patient‐derived xenograft models and cell lines A549 and PC‐9, cisplatin upregulated PD‐L1 expression, and the enhancement of PD‐L1 in cancer cell lines was in a drug dose‐dependent manner. Moreover, the depletion of PD‐L1 significantly reduced cisplatin resistance. When phosphatidylinositol 3‐kinase/protein kinase B signaling was inhibited by corresponding inhibitors, PD‐L1 expression was downregulated and apoptosis was upregulated in the cisplatin‐treated cancer cells. These results suggest that the upregulation of PD‐L1 promotes a resistance response in lung cancer cells that might be through activation of the phosphatidylinositol 3‐kinase/protein kinase B pathway and suppression of tumor‐infiltrating lymphocytes. The high expression of PD‐L1 after NAC could be an indication of therapeutic resistance and poor prognosis in patients with non‐small‐cell lung cancer.     

Impact of tumor microenvironment on the efficacy of epidermal growth factor receptor‐tyrosine kinase inhibitors in patients with EGFR‐mutant non‐small cell lung cancer

We retrospectively investigated the impact of the tumor microenvironment (TME) on the efficacy of epidermal growth factor receptor (EGFR)‐tyrosine kinase inhibitors (TKIs) as first‐line treatment in 70 patients with advanced EGFR‐mutant non‐small cell lung cancer and who were seen at Osaka City University Hospital (Osaka, Japan) between August 2013 and December 2017. Using immunohistochemical staining with 28‐8 and D7U8C Abs, the tumor proportion score was assessed for programmed cell death‐1 ligand‐1 (PD‐L1), as high (50% or more) or low (less than 50%), and ligand‐2 (PD‐L2) expression, respectively. The extent of CD8⁺ tumor‐infiltrating lymphocytes was evaluated on a scale of 0‐3, with 0‐1 as low and 2‐3 as high. The TME of the 52 evaluable pretreatment specimens was categorized into 4 subtypes, according to the respective PD‐L1 tumor proportion and CD8⁺ scores, as follows: (a) high/high (13.5%, n = 7); (b) low/low (42.3%, n = 22); (c) high/low (17.3%, n = 9); and (d) low/high (26.9%, n = 14). Expression of PD‐L2 was significantly the highest in type 1 (57.1% vs 4.5% vs 11.1% vs 7.1%, respectively; P = .0090). Response rate was significantly the lowest in type 1 (14.3% vs 81.8% vs 66.7% vs 78.6%, respectively; P = .0085). Progression‐free survival was the shortest in type 1 and the longest in type 4 (median, 2.4 vs 11.3 vs 8.4 vs 17.5 months, respectively; P = .00000077). The efficacy of EGFR‐TKIs differed according to the TME, and the phenotype with high PD‐L1 and CD8⁺ expression might be the subset that would poorly benefit from such treatment.     

Hypoxia‐inducible factor‐1α and nuclear factor‐κB play important roles in regulating programmed cell death ligand 1 expression by epidermal growth factor receptor mutants in non‐small‐cell lung cancer cells

Some driver gene mutations, including epidermal growth factor receptor (EGFR), have been reported to be involved in expression regulation of the immunosuppressive checkpoint protein programmed cell death ligand 1 (PD‐L1), but the underlying mechanism remains obscure. We investigated the potential role and precise mechanism of EGFR mutants in PD‐L1 expression regulation in non‐small‐cell lung cancer (NSCLC) cells. Examination of pivotal EGFR signaling effectors in 8 NSCLC cell lines indicated apparent associations between PD‐L1 overexpression and phosphorylation of AKT and ERK, especially with increased protein levels of phospho‐IκBα (p‐IκBα) and hypoxia‐inducible factor‐1α (HIF‐1α). Flow cytometry results showed stronger membrane co‐expression of EGFR and PD‐L1 in NSCLC cells with EGFR mutants compared with cells carrying WT EGFR. Additionally, ectopic expression or depletion of EGFR mutants and treatment with EGFR pathway inhibitors targeting MEK/ERK, PI3K/AKT, mTOR/S6, IκBα, and HIF‐1α indicated strong accordance among protein levels of PD‐L1, p‐IκBα, and HIF‐1α in NSCLC cells. Further treatment with pathway inhibitors significantly inhibited xenograft tumor growth and p‐IκBα, HIF‐1α, and PD‐L1 expression of NSCLC cells carrying EGFR mutant in nude mice. Moreover, immunohistochemical analysis revealed obviously increased protein levels of p‐IκBα, HIF‐1α, and PD‐L1 in NSCLC tissues with EGFR mutants compared with tissues carrying WT EGFR. Non‐small‐cell lung cancer tissues with either p‐IκBα or HIF‐1α positive staining were more likely to possess elevated PD‐L1 expression compared with tissues scored negative for both p‐IκBα and HIF‐1α. Our findings showed important roles of phosphorylation activation of AKT and ERK and potential interplay and cooperation between NF‐κB and HIF‐1α in PD‐L1 expression regulation by EGFR mutants in NSCLC.     

Clinical significance of programmed cell death‐ligand 1 expression and the immune microenvironment at the invasive front of colorectal cancers with high microsatellite instability

Immunotherapy is reportedly effective in colorectal cancers (CRCs) with high microsatellite instability (MSI‐H); however, the specific cell types that respond to immune checkpoint therapy are unclear. Herein, we aimed to examine the expression of programmed cell death‐ligand 1 (PD‐L1) and related proteins in MSI‐H and microsatellite‐stable (MSS) CRCs to investigate the immune microenvironment at the tumor's invasive front. The MSI status was retrospectively assessed in 499 patients undergoing surgical resection of primary CRC; of these, 48 were classified as MSI‐H. Propensity score matching was performed, and tissues from 36 and 37 patients with MSI‐H and MSS CRCs, respectively, were immunohistochemically evaluated for PD‐L1, PD‐1, CD8 and CD68. PD‐L1 expression was evaluated separately for tumor cells (PD‐L1 [T]) and tumor‐infiltrating myeloid cells in the stroma (PD‐L1 [I]). PD‐L1 (T) was positive in only 5.4% and 36.1% of MSS and MSI‐H CRCs, while PD‐L1 (I) was positive in 27% and 72.2% of these CRCs, respectively. The PD‐L1 (T) and PD‐L1 (I) expression levels in MSI‐H CRCs significantly correlated with poor differentiation, lymphatic invasion and vascular invasion (p < 0.05), and with early‐stage adenocarcinoma and high budding grade (p < 0.05), respectively. Significantly more PD‐L1 (I), CD8‐positive cells and CD68‐positive macrophages were present at the invasive front than in the central tumor in MSI‐H CRCs (p < 0.005). PD‐L1 was expressed on both tumor cells and CD68/CD163‐positive (M2) macrophages at the invasive front of MSI‐H CRCs. In conclusion, PD‐L1‐positive tumor cells and M2‐type tumor‐associated macrophages may contribute to tumor invasion and immune escape at the invasive front.     

Programmed cell death ligand‐1 protein expression and CD274/PD‐L1 gene amplification in colorectal cancer: Implications for prognosis

Programmed cell death ligand‐1 (PD‐L1) detection assays have not been standardized for patients with colorectal cancer, and the prognostic value of PD‐L1 expression is unclear. We compared the PD‐L1 expression patterns in colorectal cancer samples using various immunohistochemical assays using 3 primary PD‐L1 antibodies (assay 1, MIH1; assay 2, E1L3; and assay 3, 22C3) and investigated the prognostic implication of PD‐L1 expression using each. Additionally, PD‐L1 gene amplification was evaluated using FISH. The percentage scorings and positivity rates of the 3 assays differed; the degrees of correlation and concordance between assays 2 and 3 were relatively high, whereas assay 1 was an outlier. Multivariate analyses indicated that PD‐L1 positivity in tumor cells and its negativity in tumor‐infiltrating lymphocytes were independent predictors of poorer overall and disease‐free survival in patients with colorectal cancer. PD‐L1 gene amplification was found in 2 patients (PD‐L1/CEP ratio, 5.60 and 5.84, respectively); both had strong PD‐L1 expression according to immunohistochemistry. Overall, our study showed that PD‐L1 expression status in tumor and immune cells is an independent prognostic factor in patients with colorectal cancer. Standardizations of both PD‐L1 detection using immunohistochemistry and the cut‐off for positivity are necessary. Finally, PD‐L1 gene amplification was found in a small fraction of samples, suggesting the possibility of an ancillary test for PD‐L1 evaluation.     

Programmed death ligand‐1 is associated with tumor infiltrating lymphocytes and poorer survival in urothelial cell carcinoma of the bladder

Drugs blocking programmed death ligand‐1 (PD‐L1) have shown unprecedented activity in metastatic and unresectable bladder cancer. The purpose of the present study was to investigate the expression, clinical significance and association of PD‐L1 with tumor‐infiltrating lymphocytes (TIL) in resectable urothelial cell carcinoma of the bladder (UCB). In this retrospective study, 248 UCB patients who received radical cystectomy or transurethral resection were examined. Immunohistochemistry was used to evaluate PD‐L1 expression and stromal CD8⁺ TIL, Th1 orientation T cell (T‐bet⁺) and PD‐1⁺ TIL densities within the intratumoral regions and associated stromal regions. Of the 248 specimens, 23% showed PD‐L1 expression in tumor cells and 55% in tumor‐infiltrating immune cells. CD8⁺ TIL, T‐bet⁺ TIL and PD‐1⁺ TIL were distributed throughout the tumor tissues and were more frequently distributed in stromal regions than in intratumoral regions. PD‐L1⁺ tumor cells and PD‐L1⁺ immune cells were positively associated with aggressive clinical features (all P < .05). Both PD‐L1⁺ tumor cells and PD‐L1⁺ immune cells were associated with poorer recurrence‐free and overall survival (all P < .05). Multivariate analysis showed that PD‐L1⁺ immune cells were an independent prognostic factor for overall (P = .001) and recurrence‐free survival (P = .024). Notably, high stromal CD8⁺ TIL and PD‐1⁺ TIL density were associated with poorer overall survival (P = .031 and P = .001, respectively). In the stroma, CD8⁺ TIL density has strong positive association with PD‐L1⁺ immune cells and PD‐1⁺ TIL density (all P < .0001). These results suggested that an exhausted immune state occurred in the tumor stroma in UCB. Further clinical development of immune‐checkpoint inhibitors may be effective for resectable patients with UCB.     

Tumor cell expression of programmed cell death‐1 ligand 1 is a prognostic factor for malignant melanoma

BACKGROUND:

Melanoma tends to be refractory to various immunotherapies because of tumor‐induced immunosuppression. To investigate the mechanism underlining the immunosuppression of melanoma patients, the authors focused on programmed cell death‐1 (PD‐1)/PD‐1 ligand 1 (PD‐L1) interaction between tumor cells and T cells.

METHODS:

Melanoma specimens were collected from 59 primary tumors, 16 lymph nodes, and 4 lesions of in‐transit metastasis. Specimens stained with anti‐PD‐L1 monoclonal antibodies were digitalized to jpg files. To evaluate the intensity of PD‐L1 expression, histograms were used, and the red density (RD) was measured. PD‐1 expression on T cells was analyzed in blood samples from 10 patients who had stage IV melanoma and in 4 samples of in‐transit metastases.

RESULTS:

Twenty‐five patients comprised the “low” PD‐L1 expression group (RD value, <90), and 34 patients comprised the “high” group (RD value, ≥90). Breslow tumor thickness in the high‐expression group was significantly higher than in the low‐expression group. Univariate and multivariate analyses revealed that the overall survival rate of the high‐expression group was significantly lower than that of the low‐expression group. In all patients with stage IV disease who were examined, both CD8‐positive and CD4‐positive T cells had significantly higher PD‐1 expression levels in the peripheral blood. Tumor‐infiltrating T cells expressed high levels of PD‐1, and its expression was elevated further during the clinical course.

CONCLUSIONS:

The current results indicated that there is a correlation between the degree of PD‐L1 expression and the vertical growth of primary tumors in melanoma. Multivariate analysis demonstrated that PD‐L1 expression is an independent prognostic factor for melanoma. Cancer 2010. © 2010 American Cancer Society.     

Checkpoint inhibitors in triple‐negative breast cancer (TNBC): Where to go from here

Advances in cancer immunotherapy and a growing body of research have focused on the role of the antitumor response in breast cancer. Triple‐negative breast cancer (TNBC) is the most immunogenic breast cancer subtype, and there is strong evidence that tumor‐infiltrating lymphocytes in TNBC have prognostic value and are associated with clinical outcome and improved survival. Evading antitumor immunity is a hallmark for the development and progression of cancer. Immunotherapy studies have focused on the role of the programmed cell death‐1 (PD‐1) receptor/programmed death‐ligand 1 (PD‐L1) pathway in maintaining immunosuppression in the tumor microenvironment. Blockade of the PD‐1/PD‐L1 axis has emerged as a promising therapeutic option to enhance antitumor immunity and is actively being investigated in TNBC, with encouraging results. In this article, the authors review the current literature on checkpoint inhibitors in TNBC with a focus on PD‐1/PD‐L1 antibodies and discuss combination strategies and novel approaches for improving antitumor immunity and clinical outcome. Cancer 2018;124:2086‐103 . © 2018 American Cancer Society.     

Human T‐cell lymphotropic/leukemia virus type 1 (HTLV‐1) Tax‐specific T‐cell exhaustion in HTLV‐1‐infected individuals

Adult T‐cell leukemia/lymphoma (ATL) is caused by Human T‐cell lymphotropic/leukemia virus type 1 (HTLV‐1), and a higher HTLV‐1 provirus load in PBMC is a risk factor for ATL development. Here, we document a significant inverse correlation between the function of HTLV‐1 Tax‐specific CTL (Tax‐CTL), as assessed by ex vivo cytokine production in response to cognate peptide, and the HTLV‐1 provirus load in PBMC in both HTLV‐1 asymptomatic carriers (AC) (Spearman rank correlation coefficient [Rs] = ?0.494, P = .037, n = 18) and ATL patients (Rs = ?0.774, P = .001, n = 15). There was also a significant correlation between the HTLV‐1 provirus load and the percentage of PD‐1‐positive Tax‐CTL in both HTLV‐1 AC (Rs = 0.574, P = .013) and ATL patients (Rs = 0.676, P = .006). Furthermore, the percentage of PD‐1‐positive Tax‐CTL was inversely correlated with their function in HTLV‐1 AC (Rs = ?0.542, P = .020), and ATL patients (Rs = ?0.639, P = .010). These findings indicate that the function of Tax‐CTL decreased as their programmed cell death protein 1 (PD‐1) levels increased, parallel to the increased HTLV‐1 provirus load in PBMC. We propose that functional Tax‐CTL are crucial for determining the HTLV‐1 provirus load in PBMC, not only in HTLV‐1 AC, but also in ATL, and that PD‐1 expression levels are reliable markers of Tax‐CTL function. Thus, modulating the immunological equilibrium between Tax‐CTL and HTLV‐1‐infected cells to achieve dominance of functional effectors could represent an ideal strategy for controlling HTLV‐1‐associated disease.     

PD‐L1 expression associated with worse survival outcome in malignant pleural mesothelioma

1 Aim

There is currently a need to identify prognostic biomarkers to assist in a risk adopted approach in treatment of malignant pleural mesothelioma (MPM). Expression of programmed death ligand 1 (PD‐L1) has been studied as a prognostic biomarker in a number of tumors given its central role in antitumoral immune response evasion. Four previously published analyses found PD‐L1 positivity to be an adverse survival prognostic factor in MPM. This study aims to further investigate the relationship between PD‐L1 expression in mesothelioma tissues and survival outcome.

2 Methods

Clinical data of MPM patients from a single institution between 2006 and 2016 were reviewed. Patient's archived tissues were stained with PD‐L1 (Clone Ventana SP263). PD‐L1 positivity was defined as > 1% membranous staining regardless of intensity.

3 Results

Data from fifty eight patients were analyzed. Median age was 73, majority was male (49, 84%) and had ECOG between 0 and 2 (46, 79%). Most common histopathological subtype was epithelioid (42, 72%), 9 (16%) biphasic subtype and 7 (12%) sarcomatoid. Thirty one patients (53%) received best supportive care and twenty seven patients (47%) received chemotherapy or combination treatment. Forty‐two patients had positive PD‐L1 expression (72.4%). The median survival time for PD‐L1 negative group is 15.5 months and 6 months for the positive group. Positive PD‐L1 expression is independently correlated with worse prognosis (HR = 2.02; 95% CI, 1.005–4.057; P‐value = 0.0484).

4 Conclusions

Our analysis found a higher percentage of MPM patients with positive PD‐L1 (> 1%) compared to other studies. Highly positive PD‐L1 expression was associated with statistically significantly lower median survival time.     

Programmed death‐ligand 1 is prognostic factor in esophageal squamous cell carcinoma and is associated with epidermal growth factor receptor

Programmed death‐ligand 1 (PD‐L1) expression either indicates immune inhibitory status or concurrent immune response. Although the relationship between PD‐L1 and clinical outcomes has been studied widely in recent years, its role in prognosis of esophageal squamous cell carcinoma (ESCC) remains unclear. Here, we assessed the significance of PD‐L1 in ESCC and its association with epidermal growth factor receptor (EGFR) and radiation response. We found that PD‐L1 was present both on the surface of tumor cells and tumor‐infiltrating immune cells. Patients with tumor‐infiltrating immune cell PD‐L1 expression had better survival. PD‐L1 expression on immune cells was an independent prognostic factor for patients with ESCC. PD‐L1 expression either on tumor‐infiltrating immune cells or tumor cells was negatively associated with EGFR expression. EGFR/PD‐L1 pairs could separate the survival between EGFR low/PD‐L1 positive and EGFR high/PD‐L1 negative groups. In ESCC cell lines with EGFR high expression, PD‐L1 expression was induced significantly when EGFR signaling was activated by radiation and was dramatically inhibited by an EGFR tyrosine kinase inhibitor. In conclusion, tumor‐infiltrating immune cell PD‐L1 expression is an independent prognostic factor for ESCC, and the association between EGFR and PD‐L1 is vital to determining survival. It is important to consider radiotherapy‐induced imbalance of pro‐tumor and anti‐tumor immune response. A combination of radiotherapy and PD‐L1‐targeted therapy could be a promising therapeutic strategy for ESCC patients.     

PD‐L1 expression of the residual tumor serves as a prognostic marker in local advanced breast cancer after neoadjuvant chemotherapy

This study sought to investigate the prevalence of programmed death ligand 1 (PD‐L1) and its prognostic value in patients with residual tumors after neoadjuvant chemotherapy (NCT) for locally advanced breast cancer. A total of 309 patients considered as non‐pathological complete responders (non‐pCR) after NCT followed by mastectomy were selected. The expression of PD‐L1 and tumor‐infiltrating lymphocytes (TILs) in residual breast cancer cells was assessed by immunohistochemistry in surgical specimens. The median density was used to classify PD‐L1 expression from low to high. The prognostic value of various clinicopathological factors was evaluated. The expression of PD‐L1 was more commonly observed in patients with low levels of total TILs (p < 0.001), high levels of FOXP3+ TILs (p < 0.001) and low levels of CD8+ TILs (p < 0.001). This served as an independent prognostic factor for both relapse‐free survival (Hazard ratio = 1.824, p = 0.013) and overall survival (OS) (Hazard ratio = 2.585, p = 0.001). High expression of PD‐L1 was correlated to worse survival, which is most significantly observed in triple‐negative patients. Patients classified as PD‐L1‐high/CD8‐low exhibited relatively unfavorable survival, whereas patients with either low expression of PD‐L1 or high expression of CD8 had similar outcomes. PD‐L1 expression in residual tumor can be used as a prognostic marker in non‐pCR patients after receiving NCT for breast cancer, which highlights the importance of immune evasion in the therapeutic vulnerability of chemoresistant cancer cells as well as the potential of anti‐PD‐L1 treatments in non‐pCR responders.     

Serum sPD-1 and sPD-L1 as Biomarkers for Evaluating the Efficacy of Neoadjuvant Chemotherapy in Triple-Negative Breast Cancer Patients

BackgroundNeoadjuvant chemotherapy (NAC) is widely administered in the primary treatment of triple-negative breast cancer (TNBC). However, serum biomarkers for evaluating or monitoring the curative efficacy of NAC have not been established. Accumulating data have shown that soluble programmed death 1 (sPD-1) and its ligand (sPD-L1) might be potential biomarkers for evaluating the curative efficacy of chemotherapy and patient prognosis in several cancers but not yet in breast cancer.Patients and MethodsBlood specimens were obtained from 66 TNBC patients who received NAC and 59 healthy women. The serum concentrations of sPD-1 and sPD-L1 were measured by enzyme-linked immunosorbent assay.ResultsCompared to healthy women, the serum concentration of sPD-1 was significantly elevated in TNBC patients before NAC (549.3 ± 58.76 pg/mL vs. 379.2 ± 17.30 pg/mL, P = .007), but there was only an increase tendency for sPD-L1 (227.7 ± 23.99 pg/mL vs. 195.0 ± 8.49 pg/mL, P = .22). The serum levels of sPD-1 and sPD-L1 before NAC in TNBC patients increased with tumor stage (P = .038 and .030, respectively). Patients who experienced complete or partial remission after NAC had significantly decreased serum levels of sPD-1 and sPD-L1 compared to patients with a poor response to NAC (P = .019 and .021, respectively).ConclusionSerum levels of sPD-1 and sPD-L1 could be used as noninvasive biomarkers for evaluating the malignancy of TNBC before NAC and for predicting the NAC response in TNBC patients.     

Accurate expression of PD‐L1/L2 in lung adenocarcinoma cells: A retrospective study by double immunohistochemistry

The percentage of programmed death ligand 1 (PD‐L1) positivity in cancer cells, named as the tumor proportion score, is considered to be a predictive biomarker for anti‐PD‐1/PD‐L1 therapy in lung cancer. PD‐L1 is expressed on not only cancer cells but also on immune cells, including macrophages. Although previous studies related to PD‐L1/2 expression in cancer tissues have been generally based on single immunohistochemistry (IHC), in the present study, we attempted to evaluate accurate PD‐L1/2 expression in cancer cells in lung adenocarcinoma cells using double IHC to also evaluate macrophages. Of the 231 patients, PD‐L1 expression was negative in 169 patients (73.2%), 1%‐49% positive in 47 patients (20.3%), and ≥50% positive in 15 patients (6.5%). Interestingly, PD‐L1 positivity was decreased when using double IHC compared with the estimation by single IHC. High PD‐L1 expression was associated with high‐grade cancer cells and in higher stage cancer. PD‐L2 was negative in 109 patients (47.2%), 1%‐49% positive in 50 patients (21.6%), and ≥50% positive in 72 patients (31.2%). The number of PD‐L2‐positive patients was increased in cases that had an epidermal growth factor receptor (EGFR) mutation and in lower stage cancer. Thirty‐five patients (15.2%) were positive for both PD‐L1 and PD‐L2, whereas 81 patients (35.1%) were negative for both PD‐L1 and PD‐L2. Log‐rank analysis showed that progression‐free survival and overall survival were significantly the longest in the PD‐L1‐negative and PD‐L2‐positive groups (P < .0001 and P = .0120). We observed lower PD‐L1 or PD‐L2 expression in lung adenocarcinoma than previously reported. Double IHC for macrophages may help clinicians to evaluate PD‐L1 or PD‐L2 expression specifically in cancer cells.     

Long‐term efficacy and predictive correlates of response to nivolumab in Japanese patients with esophageal cancer

The long‐term efficacy of nivolumab in esophageal squamous cell carcinoma and its association with disease biomarkers are currently not well known. Therefore, we investigated the association in Japanese patients with treatment‐refractory advanced esophageal cancer who participated in an open‐label, single‐arm, multicenter phase II study. Patients received nivolumab 3 mg/kg i.v. every 2 weeks until disease progression or unacceptable toxicity, and were followed up for 2 years after the initial dosing of the last patient. Archival tissue samples were collected before treatment and analyzed for programmed death ligand‐1 (PD‐L1) and CD8⁺ status of tumors and tumor‐infiltrating lymphocytes (TILs) and human leukocyte antigen class 1. Efficacy end‐points included objective response rate (ORR), overall survival (OS), progression‐free survival (PFS), time to response, and duration of response. Of 65 enrolled patients (83% male), 64 were evaluable for efficacy and 41 (63%) for biomarkers. The ORR, median OS, and survival rate were 17.2%, 10.78 months, and 17.2%, respectively. Time to response was 1.45 months and duration of response was 11.17 months. The PD‐L1 positivity of tumor cells was possibly associated with better PFS (2.04 vs 1.41 months, cut‐off 1%) and OS (11.33 vs 6.24 months, cut‐off 1%). Median OS was prolonged in patients with a median number of TILs greater than 63.75% vs 63.75% or less (11.33 vs 7.85 months). Nivolumab showed continued long‐term efficacy, as seen by the stability of PFS and OS, in Japanese patients with esophageal squamous cell carcinoma. Further investigation of PD‐L1 tumor expression and TILs as potential biomarkers for predicting patients likely to benefit from nivolumab therapy is warranted.     

The PD‐1/PD‐L1 axis and human papilloma virus in patients with head and neck cancer after adjuvant chemoradiotherapy: A multicentre study of the German Cancer Consortium Radiation Oncology Group (DKTK‐ROG)

We examined the prognostic role of PD‐1+ and CD8+ tumor infiltrating lymphocytes (TILs), and PD‐L1+ cells in patients with squamous cell carcinoma of the head and neck (SCCHN) treated with surgery and postoperative chemoradiotherapy (CRT). FFPE samples from 161 patients were immunohistochemically stained for PD‐1, CD8 and PD‐L1. The immune marker expression was correlated with clinicopathologic characteristics, and overall survival (OS), local progression‐free survival (LPFS) and distant metastases free‐survival (DMFS), also in the context of HPV16 DNA/p16 status. The median follow‐up was 48 months (range: 4–100). The 2‐year‐OS was 84.1% for the entire cohort. High PD‐1 and PD‐L1 expression were more common in patients with positive HPV16 DNA (p < 0.001 and p = 0.008, respectively) and high infiltration by CD8+ TILs (p < 0.001 for both markers). High PD‐L1 expression correlated with superior OS (p = 0.025), LPFS (p = 0.047) and DMFS (p = 0.048) in multivariable analysis, whereas no significance could be demonstrated for PD‐1. Patients with CD8^high/PD‐L1^high expression had favorable outcome (p < 0.001 for all endpoints) compared to other groups. We validated the superior OS data on CD8^high/PD‐L1^high using the Cancer Genome Atlas TCGA dataset (n = 518; p = 0.032). High PD‐L1 expression was a favorable prognostic marker in HPV16‐negative but not HPV16‐positive patients. In conclusion, HPV‐positive tumors showed higher expression of immune markers. PD‐L1 expression constitutes an independent prognostic marker in SCCHN patients post‐adjuvant CRT. In conjunction with CD8 status, these data provide an important insight on the immune contexture of SCCHN and are directly relevant for future treatment stratification with PD‐1/PD‐L1 immune checkpoint inhibitors to complement CRT.     

Combination immunotherapy with interleukin‐2 surface‐modified tumor cell vaccine and programmed death receptor‐1 blockade against renal cell carcinoma

Immunotherapy may be an effective way to prevent postoperative recurrence of renal cell carcinoma. Streptavidin‐interleukin‐2 (SA‐IL‐2) surface‐modified tumor cell vaccine developed through our protein‐anchor technology could induce specific antitumor T‐cell responses, but this immunotherapy cannot completely eradicate the tumor. These effector T cells highly expressed programmed death receptor‐1 (PD‐1), and the expression of programmed death ligand‐1 (PD‐L1) in the tumor environment also was upregulated after SA‐IL‐2‐modified vaccine therapy. PD‐1/PD‐L1 interaction promotes tumor immune evasion. Adding PD‐1 blockade to SA‐IL‐2‐modified vaccine therapy increased the number of CD4⁺, CD8⁺ and CD8⁺interferon‐γ⁺ but not CD4⁺Foxp3⁺ T cells. PD‐1 blockade could rescue the activity of tumor‐specific T lymphocytes induced by the SA‐IL‐2‐modified vaccine. Combination therapy delayed tumor growth and protected mice against a second Renca cells but not melanoma cells challenge. Taken together, PD‐1 blockade could reverse immune evasion in the treatment with SA‐IL‐2‐modified vaccine, and eventually induce a stronger specific antitumor immune response against renal cell carcinoma.     

Prognostic value of programmed death‐ligand 1 expression in patients with stage III colorectal cancer

The programmed death‐1/programmed death‐ligand 1 (PD‐L1) pathway is a negative feedback pathway that suppresses the activity of T cells. Previous studies reported that high PD‐L1 expression on tumor cells (TC) was associated with poor survival in patients with colorectal cancer; however, the prognostic evaluation of these studies was limited because they included patients at various disease stages. The purpose of the present study was to evaluate the relationship between PD‐L1 status in the immune microenvironment and the clinicopathological features of stage III colorectal cancer. Two hundred and thirty‐five patients were included in the analysis. PD‐L1 expression on TC and tumor‐infiltrating mononuclear cells (TIMC) was evaluated by immunohistochemistry. The median follow‐up of thisi study was 52.9 months. A total of 8.1% of stage III colorectal cancer showed high PD‐L1 expression on TC and 15.3% showed high PD‐L1 expression on TIMC. Patients with high PD‐L1 expression on TC had significantly shorter disease‐free survival (DFS) than patients with low expression (hazard ratio [HR] 2.36; 95% confidence interval [CI], 1.21–4.62; P = 0.012). In addition, patients with high PD‐L1 expression on TIMC were associated with longer DFS than patients with low expression (HR 0.40; 95% CI, 0.16–0.98; P = 0.046). These findings suggest that PD‐L1 expression status may be a new predictor of recurrence for stage III colorectal cancer patients and highlight the necessity of evaluating PD‐L1 expression on TC and TIMC separately in the tumor microenvironment.