Tumor infiltrated immune cell types support distinct immune checkpoint inhibitor outcomes in patients with advanced non-small cell lung cancer.

The evaluation of PD-L1 expression alone has limitations in predicting clinical outcome in immune-checkpoint inhibitors (ICI). This study aimed to evaluate the predictive and prognostic effects of the presence of various immune cells in pretreatment tissue samples and to identify determinants associated with response in patients with advanced non-small cell lung cancer (NSCLC) treated with PD-1 blockade. Immune cell distribution was heterogeneous and the most dominant immune cell type was T cells. Patients with durable clinical benefit (DCB) showed significantly higher PD-L1 expression. The ratio of tumor/stroma region of T cell, B cell, and macrophage was significantly higher in patient with DCB. High intratumoral T- and B-cell density (≥median) was associated with DCB in the low PD-L1 expression (<50%) group. In univariate analyses, the overall survival (OS) benefit was shown according to intratumoral B-cell density (p = 0.0337). The incidence of hyperprogressive disease (HPD) was 13.0%. The Chi-square test revealed that HPD was significantly associated with intratumoral B-cell density but not T-cell or macrophage density. Our results demonstrate different predictive and prognostic values for infiltrating immune cells in tumor tissue, which may help in selecting patients for ICI.

ERK inhibitor ASN007 effectively overcomes acquired resistance to EGFR inhibitor in non-small cell lung cancer.

The emergence of acquired resistance limits the long-term efficacy of EGFR tyrosine kinase inhibitors (EGFR TKIs). Thus, development of effective strategies to overcome resistance to EGFR TKI is urgently needed. Multiple mechanisms to reactivate ERK signaling have been successfully demonstrated in acquired resistance models. We found that in EGFR mutant non-small cell lung cancer (NSCLC) patients, acquired resistance to EGFR TKIs was accompanied by increased activation of ERK. Increased ERK activation was also found in in vitro models of acquired EGFR TKI resistance. ASN007 is a potent selective ERK1/2 inhibitor with promising antitumor activity in cancers with BRAF and RAS mutations. ASN007 treatment impeded tumor cell growth and the cell cycle in EGFR TKI-resistant cells. In addition, combination treatment with ASN007 and EGFR TKIs significantly decreased the survival of resistant cells, enhanced induction of apoptosis, and effectively inhibited the growth of erlotinib-resistant xenografts, providing the preclinical rationale for testing combinations of ASN007 and EGFR TKIs in EGFR-mutated NSCLC patients. This study emphasizes the importance of targeting ERK signaling in maintaining the long-term benefits of EGFR TKIs by overcoming acquired resistance.

Role of Circulating Tumor DNA Profiling in Patients with Non-Small Cell Lung Cancer Treated with EGFR Inhibitor.

OBJECTIVES: During targeted therapy, tumor heterogeneity can drive the evolution of multiple tumor subclones harboring unique resistance mechanisms. Sequential profiling of plasma cell-free DNA (cfDNA) provides a noninvasive method for early detection of patient progression. We investigated whether the genetic dynamics detected in cfDNA during treatment can act as a predictive or prognostic marker of outcome. METHODS: Patients with advanced EGFR-mutated non-small cell lung cancer (NSCLC) were included for consecutive blood sampling during EGFR-tyrosine kinase inhibitor (TKI) treatment. Blood samples were serially collected from patients at baseline, first follow-up, and progression. Extracted cfDNA was analyzed with next-generation sequencing. RESULTS: Serial plasma samples (n = 187) from 63 patients were analyzed, and 44 patients showed circulating tumor DNA (ctDNA). EGFR mutations were detected in 36 of the 44 patients at baseline (81.8%). EGFR mutations were no longer detected in 19 of 36 shedders (52.8%) at 2 months after EGFR-TKI treatment and rebounded with resistant EGFR mutations (T790M or C797S) at progression. Other driver mutations such as KRAS G12D and BRAF V600E were found at baseline regardless of tissue EGFR status, suggesting tumor heterogeneity. Detection of ctDNA (shedder) at baseline associated with poor overall survival (p = 0.04) compared to nonshedder. Furthermore, in patients showing EGFR mutations in plasma at baseline, the clearing rate of those during the first 8 weeks of treatment served as a positive predictor for clinical outcome. CONCLUSION: Longitudinal liquid biopsies capture spatial and temporal heterogeneity underlining resistance to EGFR-TKIs in NSCLC. Thus, ctDNA monitoring during EGFR-TKI treatment is useful for detecting resistance mutations or predicting response. Dense serial monitoring using blood enables early prediction of treatment failure and provides a window of opportunity for well-timed intervention.

High concordance of actionable genomic alterations identified between circulating tumor DNA-based and tissue-based next-generation sequencing testing in advanced non-small cell lung cancer: The Korean Lung Liquid Versus Invasive Biopsy Program.

BACKGROUND: Because of the growing number of actionable biomarkers in non-small cell lung cancer (NSCLC), sufficient tissue availability for testing is becoming a greater challenge. Liquid biopsy offers a potential solution by complementing standard tissue-based methods. In this study, the authors analyzed the concordance of actionable genomic alterations sequenced from circulating tumor DNA (ctDNA; Guardant360) and tissue (Oncomine Focus Assay). METHODS: From September 2015 to May 2018, 421 paired plasma and tissue samples from patients with advanced NSCLC who had previously undergone tissue testing by standard methods were collected. Both types of samples were available for 287 patients (262 in cohort 1 [treatment-naive] and 25 in cohort 2 [treatment failure]), and only 1 sample type was available for 134 patients (50 in cohort 3 [plasma only] and 84 in cohort 4 [tissue only]). RESULTS: In cohort 1, 198 samples (77.6%) showed concordance between tissue and plasma next-generation sequencing (NGS). Among the discordant cases, plasma testing detected additional genomic alterations in 11 patients (4.2%). In 50 patients without tissue-based NGS results (cohort 3), the ctDNA-based test detected genomic alterations in 20 samples (40.0%). The median allele frequency (AF) of mutations identified with ctDNA-based NGS (0.74%) was lower than that identified with the tissue-based NGS test (13.90%). Clinical responses to matched targeted therapy occurred, regardless of the ctDNA AF. Upfront ctDNA-based testing identified 60.4% of patients with genomic alterations. In addition, ctDNA-based testing uncovered 12.0% more actionable alterations when it was performed after tissue-based NGS testing. CONCLUSIONS: The results indicate that a ctDNA-based test identifies additional patients with actionable genomic alterations and could, therefore, be used to complement traditional tissue-based testing for NSCLC. LAY SUMMARY: Circulating tumor DNA (ctDNA)-based next-generation sequencing (NGS) testing is becoming essential as the number of actionable genomic biomarker increases for the treatment selection of non-small cell lung cancer. This study demonstrates the additive value of ctDNA-based testing in addition to tissue-based NGS and standard of care-based biomarker testing for detecting additional patients with actionable genomic alterations. Clinical responses have also been observed in patients with a low allele frequency detected by ctDNA-based NGS testing.

MDSC subtypes and CD39 expression on CD8+ T cells predict the efficacy of anti-PD-1 immunotherapy in patients with advanced NSCLC.

The major suppressive immune cells in tumor sites are myeloid derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and Treg cells, and the major roles of these suppressive immune cells include hindering T-cell activities and supporting tumor progression and survival. In this study, we analyzed the pattern of circulating MDSC subtypes in patients with non-small cell lung cancer (NSCLC) whether those suppressive immune cells hinder T-cell activities leading to poor clinical outcomes. First, we verified PMN-MDSCs, monocytic-MDSCs (M-MDSCs), and Treg cells increased according to the stages of NSCLC, and MDSCs effectively suppressed T-cell activities and induced T-cell exhaustion. The analysis of NSCLC patients treated with anti-PD-1 immunotherapy demonstrated that low PMN-MDSCs, M-MDSCs, and CD39+ CD8+ T cells as an individual and all together were associated with longer progression free survival and overall survival, suggesting PMN-MDSCs, M-MDSCs, and CD39+ CD8+ T cells frequencies in peripheral blood might be useful as potential predictive and prognostic biomarkers.

Therapeutic efficacy of cancer vaccine adjuvanted with nanoemulsion loaded with TLR7/8 agonist in lung cancer model.

Although immune checkpoint inhibitors have significantly improved clinical outcomes in various malignant cancers, only a small proportion of patients reap benefits, likely due to the low number of T cells and high number of immunosuppressive cells in the tumor microenvironment (TME) of patients with advanced disease. We developed a cancer vaccine adjuvanted with nanoemulsion (NE) loaded with TLR7/8 agonist (R848) and analyzed its therapeutic effect alone or in combination with immune checkpoint inhibitors, on antitumor immune responses and the reprogramming of suppressive immune cells in the TME. NE (R848) demonstrated robust local and systemic antitumor immune responses in both subcutaneous and orthotopic mouse lung cancer models, inducing tumor-specific T cell activation and mitigating T cell exhaustion. Combination with anti-PD-1 antibodies showed synergistic effects with respect to therapeutic efficacy and survival rate. Thus, NE (R848)-based cancer vaccines could prevent tumor recurrence and prolong survival by activating antitumor immunity and reprogramming immunosuppression.

Entrectinib resistance mechanisms in ROS1-rearranged non-small cell lung cancer.

Entrectinib is a pan-tyrosine-kinase inhibitor that targets oncogenic rearrangements in NTRK, ROS1 and ALK. The combined results of two clinical trials demonstrated the efficacy of entrectinib in ROS1-rearranged NSCLC. Because the development of drug resistance is inevitable, it would be helpful to determine the mechanisms of entrectinib resistance in a ROS1-rearranged tumor model so that future therapeutic strategies can be developed. Here, we characterized the molecular basis of resistance in entrectinib-resistant ROS1-rearranged HCC78 cells (HCC78ER cells). These cells were analyzed by next-generation sequencing and genetic profiling, which revealed the acquisition of KRAS G12C and the amplification of KRAS and FGF3. However, there were no secondary mutations in the ROS1 kinase domain. We also found that sustained ERK activation was involved in entrectinib resistance, and that combined treatment with selumetinib resensitized HCC78ER cells to entrectinib in cell viability and colony formation assays. Our data suggest that activation of the RAS signaling pathway can cause entrectinib resistance in ROS1-rearranged NSCLC, and is unlikely to be overcome by sequential single agent ROS1-targeting strategies against such tumors. Instead, co-targeting ROS1 and MEK may be an effective strategy for overcoming entrectinib resistance in ROS1-rearranged NSCLC.

Characteristics and outcomes of RET-rearranged Korean non-small cell lung cancer patients in real-world practice.

OBJECTIVE: Since the first discovery of rearranged during transfection (RET) fusion in lung adenocarcinoma in 2011, two tyrosine kinase inhibitors, namely vandetanib and cabozantinib, are currently available. Despite favorable outcomes in systemic control, the intracranial therapeutic response remains insufficient. In this study, the clinical characteristics and outcomes of non-small cell lung cancer (NSCLC) patients with RET rearrangements were analyzed. METHODS: Patients with NSCLC harboring RET fusion who received treatment between January 2006 and January 2018 were analyzed. RET rearrangement was identified by FISH or NGS. RESULTS: A total of 59 patients were identified. About half of the patients were female (47.5%) and never smokers (50.9%). Most patients had adenocarcinoma (89.8%). A total of 17 patients (28.8%) had an intracranial lesion at the initial diagnosis of stage IV disease, and 11 additional patients (18.6%) developed intracranial metastases during follow-up. The median time to development of intracranial metastases was 19.0 months (95% CI: 9.6-28.5), resulting in a >60% cumulative incidence of brain metastasis at 24 months. The systemic efficacy of pemetrexed-based regimens was favorable with progression-free survival of 9.0 (95% CI: 6.9-11.2) and OS of 24.1 (95% CI: 15.2-33.0) months. The median progression-free survival for vandetanib and immunotherapy was 2.9 (95% CI: 2.0-3.8) and 2.1 (95% CI: 1.6-2.6) months, respectively. CONCLUSIONS: Given the likelihood of RET-rearranged NSCLC progressing to intracranial metastases and the absence of apparent clinical benefit of currently available targeted or immunotherapeutic agents, development of novel treatment with higher selectivity and better penetration of the blood-brain barrier remains a priority.

AZD9291 overcomes T790 M-mediated resistance through degradation of EGFR(L858R/T790M) in non-small cell lung cancer cells.

The discovery of activating mutations of epidermal growth factor receptor (EGFR) has resulted in the development of more effective treatments for non-small cell lung cancer (NSCLC). Although first-generation EGFR tyrosine kinase inhibitors (EGFR TKIs) provide significant clinical benefit, acquired resistance often occurs, most commonly (>50 %) via a T790 M resistance mutation. Although AZD9291 is selective for both T790 M and activating EGFR mutations over wild-type EGFR, it is highly active when T790 M is present, especially EGFR(L858R/T790M), and modestly active when T790 M is absent. The aim of this study was to elucidate the underlying mechanism of the high sensitivity of NSCLC cells harboring EGFR(L858R/T790M) to AZD9291. In H1975 cells harboring EGFR(L858R/T790M), AZD9291 potently inhibited cellular growth and EGFR signaling pathways together with depletion of mutant EGFR protein. AZD9291-induced depletion of EGFR(L858R/T790M) protein was abrogated through inhibition of the proteasome with MG132. However, AZD9291 had no effect on protein levels of EGFR(WT) and EGFR(L858R). In addition, AZD9291 induced apoptosis and caused expression changes in cell cycle-related genes. Moreover, oral administration of AZD9291 as a single agent induced tumor regression in vivo in a H1975 tumor xenograft model and reduced EGFR(L858R/T790M) protein levels in xenograft tumors. Taken together, our results provide a potential mechanism for the sensitivity of EGFR(L858R/T790M) cells to AZD9291 and suggest that AZD9291 may be effective in cases of T790 M-positive EGFR resistance.

BYL719, a selective inhibitor of phosphoinositide 3-Kinase α, enhances the effect of selumetinib (AZD6244, ARRY-142886) in KRAS-mutant non-small cell lung cancer.

PURPOSE: KRAS is frequently mutated in non-small cell lung cancers (NSCLC), resulting in activation of the MEK/ERK pathway. Because there are currently no drugs that target oncogenic KRAS, MEK inhibitors have been tested clinically as a possible treatment option for patients with NSCLC. However, KRAS-mutant cancers exhibit resistance to MEK inhibitors. Therefore, a combinational strategy is necessary for effective therapy. To address this, we investigated the therapeutic effects of combining selumetinib, a MEK1/2 inhibitor, with BYL719, a PI3Kα inhibitor. METHODS: We evaluated the effects of selumetinib and BYL719 in vitro and in vivo in NSCLC cell lines. RESULTS: The combination of BYL719 and selumetinib resulted in synergistic cytotoxic activity compared with the single agents alone in KRAS-mutant NSCLC cells. At the molecular level, we found that AKT activation strongly influenced the sensitivity of KRAS-mutant NSCLC cells to selumetinib. Selumetinib upregulated phospho-AKT and phosphorylated BAD at ser136, which is responsible for intrinsic drug resistance in KRAS-mutant NSCLC cells. In contrast, inhibition of the PI3K/AKT pathway by BYL719 hindered selumetinib-induced BAD phosphorylation and increased the antitumor efficacy of selumetinib. Furthermore, selumetinib and BYL719 combination therapy showed synergy in the suppression of A549 xenograft tumor growth. On analysis of the pharmacodynamics, selumetinib and BYL719 together resulted in effective inhibition of both p-ERK and p-AKT expression in tumor tissue. CONCLUSION: Taken together, these data suggest that combination treatment with selumetinib and BYL719 is a promising therapeutic approach to overcoming resistance to MEK inhibitors.

High-throughput profiling identifies clinically actionable mutations in salivary duct carcinoma.

BACKGROUND: Salivary duct carcinoma (SDC) is a highly aggressive subtype of salivary gland cancers and there is no established standard therapy for this disease. Thus, development of molecular markers for SDC will be important to guide the diagnosis and therapy of this aggressive tumor. METHODS: We performed next-generation sequencing using the Ion Torrent AmpliSeq cancer panel, which explores the mutational status of hotspot regions in 50 cancer-associated genes, and we analyzed copy number variations (CNVs) of 21 genes by NanoString nCounter for 37 patients with SDC. Fluorescent in situ hybridization was also conducted to confirm ERBB2 gene amplification. Clinical records and tumor histopathology of the patients were retrospectively reviewed. RESULTS: Genetic alterations were detected in 29 of 37 (78.3%) tumors, including mutations in PIK3CA (N = 9, 24.3%), ERBB2 (N = 4, 10.8%), and EGFR (N = 4, 10.8%). To our knowledge, this is the first time that ERBB2 mutations have been reported in this tumor type. Both PIK3CA and ERBB2 mutation status were associated with poor overall survival, but without statistical significance. ERBB2 amplification was strong and common in SDC and almost all cases also exhibited EGFR and ERBB3 amplifications. CONCLUSIONS: This study reports the largest and most comprehensive analysis of DNA aberrations in SDC. Our results show that PIK3CA and/or ERBB2 alterations in the development of SDC might be a useful diagnostic tool and could serve as a potential therapeutic target.

Transglutaminase 2 inhibition found to induce p53 mediated apoptosis in renal cell carcinoma.

Renal cell carcinoma (RCC), the predominant form of kidney cancer, is characterized by high resistance to radiation and chemotherapy. This study shows that expression of protein cross-linking enzyme transglutaminase 2 (TGase 2) is markedly increased in 7 renal cell carcinoma (RCC) cell lines in comparison to HEK293 and other cancer cell lines, such as NCI 60. However, the key role of TGase 2 in RCC was not clear. The down-regulation of TGase 2 was found to stabilize p53 expression, thereby inducing a 3- to 10-fold increase in apoptosis for 786-O, A498, CAKI-1, and ACHN cell lines by DAPI staining. MEF cells from TGase 2(-/-) mice showed stabilized p53 under apoptotic stress to compare to MEFs from wild-type mice. TGase 2 directly cross links the DNA binding domain of p53, leading to p53 depletion via autophagy in RCC. TGase 2 and p53 expression showed an inverse relationship in RCC cells. This finding implies that induced expression of TGase 2 promotes tumor cell survival through p53 depletion in RCC.

Increased expression of transglutaminase 2 drives glycolytic metabolism in renal carcinoma cells.

Transglutaminase 2 (TGase 2) expression and glycolysis are increased in most renal cell carcinoma (RCC) cell lines compared to the HEK293 kidney cell line. Although increased glycolysis and altered tricarboxylic acid cycle are common in RCC, the detailed mechanism by which this phenomenon occurs remains to be elucidated. In the present study, TGase 2 siRNA treatment lowered glucose consumption and lactate levels by about 20-30 % in RCC cells; conversely, high expression of TGase 2 increased glucose consumption and lactate production together with decreased mitochondrial aconitase (Aco 2) levels. In addition, TGase 2 siRNA increased mitochondrial membrane potential and ATP levels by about 20-30 % and restored Aco 2 levels in RCC cells. Similarly, Aco 2 levels and ATP production decreased significantly upon TGase 2 overexpression in HEK293 cells. Therefore, TGase 2 leads to depletion of Aco 2, which promotes glycolytic metabolism in RCC cells.

A Phase 2 Study of Palbociclib for Recurrent or Refractory Advanced Thymic Epithelial Tumors (KCSG LU17-21).

INTRODUCTION: Thymic epithelial tumors (TETs) are rare but are the most common tumors of the anterior mediastinum. Platinum-based combination chemotherapy is the standard of care for such tumors and is associated with a 50% to 90% objective response rate (ORR) in metastatic disease. Nevertheless, there is no standard chemotherapeutic option after failure of platinum-based combination chemotherapy. Genetic alterations associated with the cell cycle, including pRB, p16INK4A, and cyclin D1, are most often observed in TETs. On the basis of these results, we conducted a phase 2 trial to evaluate the efficacy and safety of palbociclib in patients with recurrent or refractory advanced TETs. METHODS: This is a phase 2, multicenter, open-label, single-arm study of palbociclib monotherapy in patients with recurrent or metastatic advanced TETs who failed one or more cytotoxic chemotherapies. The patients received 125 mg of oral palbociclib daily for 21 days, followed by a 7-day break. The primary end point was progression-free survival (PFS). The secondary end points were ORR, duration of response, overall survival, and safety. RESULTS: Between August 2017 and October 2019, a total of 48 patients were enrolled. The median number of previous chemotherapies was one (range: one to four), and 21 (43.7%) of 48 patients received thymectomy. By the WHO classification, the patients were type A (n = 1), type B1 (n = 2), type B2 (n = 8), type B3 (n = 13), thymic carcinoma (n = 23), and unknown (n = 1). With a median follow-up of 14.5 months (range: 0.8-38.2), the median number of cycles of palbociclib monotherapy was 10 (range: 1-40). The ORR was 12.5% (four partial responses in thymoma and two partial responses in thymic carcinoma). The PFS at 6 months was 60.2%, and the median PFS was 11.0 months (95% confidence interval: 4.6-17.4). The median overall survival was 26.4 months (95% confidence interval: 17.4-35.4). The most common treatment-related adverse events of any grade were neutropenia (62.5%), anemia (37.5%), and thrombocytopenia (29.1%), and the most common grade 3/4 treatment-related hematologic adverse event was neutropenia (41.7%). Neutropenia above grade 3 was reversible, and there were no cases with neutropenic fever. CONCLUSIONS: Palbociclib monotherapy was well tolerated and had encouraging efficacy in patients with TETs who failed platinum-based combination chemotherapy.

Association of T Cell Senescence with Radiation Pneumonitis in Patients with Non-small Cell Lung Cancer.

PURPOSE: Associations between immunosenescence and radiation pneumonitis (RP) are largely unknown. We aimed to identify a peripheral blood T cell senescence biomarker to predict RP in patients with non-small cell lung cancer (NSCLC). METHODS AND MATERIALS: Patients with locally advanced NSCLC who received definitive concurrent chemoradiotherapy (dCRT) were prospectively registered (cohort 1, n=23; cohort 2, n=31). Peripheral blood was collected at baseline, during dCRT, and at 1 month post-dCRT. Patients were dichotomized to grade ≥2 (G2+) RP and grade 0-1 (G0-1) RP. Flow cytometry was performed to assess phenotypes and functional properties of T cell subsets. RP incidence was estimated via competing risk analysis. RESULTS: Five and six patients exhibited G2+ RP following dCRT in cohorts 1 and 2, respectively. Patients with G2+ RP exhibited a more aged T cell pool and higher frequencies of senescent CD57+CD28-CD8+ T cells than patients with G0-1 RP at baseline, during dCRT, and at 1 month post-dCRT. These senescent cells exhibited increased granzyme B, IFN-γ, and TNF-α production. Higher baseline frequency of CD57+CD28-CD8+ T cells was an independent predictor of G2+ RP (hazard ratio, 8.42; 95% confidence interval, 2.58-27.45; P<0.001). Recursive partitioning analysis revealed three distinct risk groups stratified by baseline CD57+CD28-CD8+ T cell frequency and lung V20 Gy, with 1-year cumulative G2+ RP incidences of 50.0%, 16.7%, and 0% for high-, intermediate-, and low-risk groups, respectively (P=0.002). CONCLUSIONS: Higher baseline frequencies of CD57+CD28-CD8+ T cells correlated with increased G2+ RP risks. Our results suggest the need for further investigation of the role of T cell senescence on radiation-induced organ damage.

Longitudinal Monitoring of Circulating Tumor DNA From Plasma in Patients With Curative Resected Stages I to IIIA EGFR-Mutant Non-Small Cell Lung Cancer.

INTRODUCTION: For patients with early stage EGFR-mutant-positive (EGFR-M+) NSCLC, curative surgery followed by adjuvant chemotherapy is considered the standard of care. This study evaluated the feasibility and efficacy of longitudinal monitoring of circulating tumor DNA (ctDNA) as a valuable biomarker for early detection of minimal residual disease (MRD) and provides identification of the group at high risk for recurrence in resected stages I to IIIA EGFR-M+ NSCLC. METHODS: Between August 2015 and October 2017, a total of 278 patients with curative resected, stages I to IIIA (American Joint Committee on Cancer seventh version) common EGFR-M+ NSCLC were analyzed. Radiological follow-up was accompanied with longitudinal monitoring of ctDNA using a droplet-digital polymerase chain reaction from baseline (preoperative), 4 weeks after curative surgery, and follow-up per protocol until 5 years. The primary outcomes were disease-free survival (DFS) according to the status of ctDNA positivity at landmark points and the sensitivity of longitudinal monitoring of ctDNA. RESULTS: Among 278 patients, preoperative baseline ctDNA was detected in 67 (24%) patients: 23% (stage IA), 18% (IB), 18% (IIA), 50% (IIB), and 42% (IIIA) (p = 0.06). Of patients with baseline ctDNA, 76% (51 of 67) had clearance at 4 weeks after surgery (postoperative). Patients were classified into the following three groups; group A, baseline ctDNA negative (n = 211) versus group B, baseline ctDNA positive but postoperative MRD negative (n = 51) versus group C, baseline ctDNA positive and postoperative MRD positive (n = 16). The 3-year DFS rate was significantly different among the three groups (84% for group A, 78% for group B, and 50% for group C, p = 0.02). After adjusting for clinicopathologic variables, ctDNA still remains an independent risk factor for DFS along with stage (p < 0.001) and micropapillary subtype (p = 0.02). With longitudinal monitoring of ctDNA, MRD was detected before radiological recurrence in 69% of patients with exon 19 deletion and in 20% with L858R mutation. CONCLUSIONS: These results suggest that patients with baseline ctDNA-positive or MRD-positive status were associated with poor DFS in curative resected stages I to IIIA EGFR-M+ NSCLC and that longitudinal monitoring of ctDNA, a noninvasive method, might be useful to detect early recurrence before radiological recurrence.

Prognostic value of FOXP3+ regulatory T cells for patients with locally advanced oropharyngeal squamous cell carcinoma.

BACKGROUND: Oropharyngeal squamous cell carcinoma (OPSCC) is the most common neoplasm originating at the base of the tongue or in the tonsils or soft palate. In this study, we investigated the prognostic value of FOXP3+ regulatory T cells in OPSCC. METHODS: Tumor tissues of patients with locally advanced OPSCC were analyzed using quantitative multiplex immunohistochemistry. Staining of CD8+ T cells, conventional CD4+FOXP3- T cells (Tconv cells), CD4+FOXP3+ regulatory T cells (Treg cells), CD20+ B cells, and CD68+ macrophages was performed, and cell density was evaluated in both the tumor and its stroma. RESULTS: Among the 71 patients included in this study, males constituted 93.0% of the cohort, and the median age was 59 years (range: 42-80 years). A total of 56 patients (78.9%) had a smoking history, and 53 (74.6%) patients were positive for human papillomavirus (HPV). The most frequent site of OPSCC was the tonsils (70.4%), followed by the base of the tongue (25.4%). The proportion of Treg cells was lower in the tumors of patients with HPV than in those of patients without HPV. Patients with OPSCC whose tumor Treg cell levels were above the median had longer relapse-free survival (RFS) periods than those with tumor Treg cell levels below the median (HR, 0.12; 95% CI, 0.03-0.46; p = 0.02). Our multivariate analysis identified high Treg levels (HR, 0.13; 95% CI, 0.02-1.00; p = 0.05) as an RFS factor that predicted a good prognosis. CONCLUSIONS: Our results demonstrated that high Treg cell density in locally advanced OPSCC tumors was correlated with longer RFS.

Longitudinal monitoring by next-generation sequencing of plasma cell-free DNA in ALK rearranged NSCLC patients treated with ALK tyrosine kinase inhibitors.

BACKGROUND: Patients with ALK-rearranged non-small cell lung cancer (ALK+ NSCLC) inevitably acquire resistance to ALK inhibitors. Longitudinal monitoring of cell-free plasma DNA (cfDNA) next-generation sequencing (NGS) could predict the response and resistance to tyrosine kinase inhibitor (TKI) therapy in ALK+ NSCLC. METHODS: Patients with ALK+ NSCLC determined by standard tissue testing and planned to undergo TKI therapy were prospectively recruited. Plasma was collected at pretreatment, 2 months-post therapy, and at progression for cfDNA-NGS analysis, Guardant 360. RESULTS: Among 92 patients enrolled, circulating tumor DNA (ctDNA) was detected in 69 baseline samples (75%): 43 ALK fusions (62.3%) and two ALK mutations without fusion (2.8%). Two patients showed ALK-resistance mutations after ceritinib; G1202R, and co-occurring G1202R and T1151R. Eight patients developed ALK resistance mutations after crizotinib therapy; L1196M (n = 5), G1269A (n = 1), G1202R (n = 1), and co-occurring F1174L, G1202R, and G1269A (n = 1). Absence of ctDNA at baseline was significantly associated with longer progression-free survival (PFS; median 36.1 vs. 11.4 months, p = 0.0049) and overall survival (OS; not reached vs. 29.3 months, p = 0.0200). ctDNA clearance at 2 months (n = 29) was associated with significantly longer PFS (25.4 vs. 11.6 months, p = 0.0012) and OS (not reached vs. 26.1 months, p = 0.0307) than those without clearance (n = 22). Patients with co-occurring TP53 alterations and ALK fusions at baseline (n = 16) showed significantly shorter PFS (7.28 vs. 13.0 months, p = 0.0307) than those without TP53 alterations (n = 25). CONCLUSIONS: cfDNA-NGS facilitates detection of ALK fusions and resistance mutations, assessment of prognosis, and monitoring dynamic changes of genomic alterations in ALK+ NSCLC treated with ALK-TKI.

Dynamics of Circulating Immune Cells During Chemoradiotherapy in Patients with Non-Small Cell Lung Cancer Support Earlier Administration of Anti-PD-1/PD-L1 Therapy.

PURPOSE: Chemoradiotherapy (CRT) followed by consolidation immune checkpoint inhibitors significantly improves survival in unresectable locally advanced non-small cell lung cancer. However, the optimal sequence for CRT and immune checkpoint inhibitors has not yet been established. We investigated the dynamics of peripheral blood immune cells during CRT to determine the best sequence for treatment. METHODS AND MATERIALS: Peripheral blood samples were prospectively collected pretreatment, weekly during CRT for 6 weeks, and 1 month posttreatment in 24 patients with locally advanced non-small cell lung cancer who received definitive CRT. Immune cell analysis was performed by flow cytometry. Ex vivo PD-1 blockade assays were performed by IFN-γ intracellular cytokine staining. RESULTS: Lymphopenia was prominently observed during CRT and mostly recovered 1 month post-CRT. Robust proliferation of CD8+ T cells was induced, peaking in the last week during CRT and decreasing post-CRT. The robust proliferation of CD8+ T cells led to an increase in the frequency of CD28-CD57+ replicative senescent and terminally differentiated cells post-CRT. Tumor-reactive CD8+ T cells increased during CRT and peaked in the last week. One month post-CRT, the frequency of tumor-reactive CD8+ T cells decreased and TOXhiTCF1lo terminally exhausted CD8+ T cells significantly increased. Anti-PD-1-induced functional restoration of PD-1+CD8+ T cells was maximized in the last week of CRT and significantly decreased post-CRT. CONCLUSIONS: The findings suggest that earlier administration of PD-1 blockade may be associated with superior efficacy compared with delayed administration after completion of CRT. These findings provide an immunologic rationale for optimal timing of combining immune checkpoint inhibitors with CRT in clinical trials.

CHI3L1 (YKL-40) is expressed in human gliomas and regulates the invasion, growth and survival of glioma cells.

Chitinase 3-like 1 (CHI3L1) is a secreted glycoprotein that has pleiotropic activity in aggressive cancers. In our study, we examined the expression and function of CHI3L1 in glioma cells. CHI3L1 was highly expressed in human glioma tissue, whereas its expression in normal brain tissue was very low. CHI3L1 suppression by shRNA reduced glioma cell invasion, anchorage-independent growth and increased cell death triggered by several anticancer drugs, including cisplatin, etoposide and doxorubicin, whereas CHI3L1 overexpression had the opposite effect in glioma cells. Because the invasive nature of glioma cells plays a critical role in the high morbidity of glioma, we have further defined the role of CHI3L1 in the process of glioma invasion. Downregulation of CHI3L1 results in decreased cell-matrix adhesion and causes a marked increase in stress fiber formation and cell size with fewer cellular processes. Furthermore, the expression and activity of matrix metalloproteinase-2 was also decreased in glioma cells in which CHI3L1 was knocked down. Taken together, these results suggest that CHI3L1 plays an important role in the regulation of malignant transformation and local invasiveness in gliomas. Thus, targeting the CHI3L1 molecule may be a potential therapeutic molecular target for gliomas.