OBJECTIVES:The aim of this study was to investigate the risk of TB in advanced non-small cell lung cancer (NSCLC) patients treated with Immune checkpoint inhibitors (ICI) after a platinum-based chemotherapy. MATERIALS AND METHODS:A nationwide population-based retrospective cohort study using National health insurance dataset was designed. Patients who were diagnosed as lung cancer between September 1st, 2017 and August 31st, 2018 in South Korea were selected. Among them, those with NSCLC who initiated a platinum-based chemotherapy within 3 months were finally included and followed up until December 31st, 2018. Patients who received nivolumab, pembrolizumab, and atezolizumab within study period were classified as the ICI group. Cox proportional hazard model with time-varying covariates was used to determine effects of the duration of conventional chemotherapy, ICI, and consecutive use of systemic steroid on TB. RESULTS:A total of 6335 patients were enrolled with 3568.7 years of total follow-up period. Among them, 899 patients underwent ICI treatment. Within the follow-up period, 15 TB cases were identified in the ICI group (incidence: 2582.5 per 100,000 person-years) and 63 TB cases were found in the conventional chemotherapy group (incidence: 2108.5 per 100,000 person-years). In a multivariable Cox proportional hazard model, treatment with ICI was not a significant risk factor for TB development (hazard ratio (HR): 1.21, 95 % confidence interval (CI): 0.45-3.26,p =  0.700). Instead, prolonged use of steroid was associated with an increased TB risk (HR: 1.91, 95 %CI: 0.89-4.08, p =  0.095), although its statistical significance was dependent on the operational definition of the effect duration. Previous TB history and older age were independent risk factors for TB disease. CONCLUSION:In this real-world study, additional treatment with ICI did not increase the risk of TB in advanced NSCLC patients who underwent a cytotoxic chemotherapy. However, TB incidence in these patients was high regardless of ICI treatment. CLASSIFICATIONS:Systemic Treatments.

Oncogenic KRAS-mutant lung cancers remain treatment refractory. A better understanding of the immune response of KRAS-mutant lung cancers is required to facilitate the development of potential therapeutic strategies. Regulatory T cells (Tregs) are a subset of immune cells that promote tumor progression through suppressing anti-tumor immune response. Here, we used Kras lung cancer mice to examine the characteristics of tumor-infiltrating Tregs. In tumor-bearing animals, Tregs are increased during tumor progression. Of note, a majority of Tregs that localized in lung tumors of Kras-mutant mice expressed ST2, a receptor for IL-33, which are different from Tregs in secondary lymphoid organs. To investigate the function of local Tregs influencing immune response in primary lung tumor development, we used anti-ST2 antibody to deplete Tregs in lung tumors of Kras-mutant mice. Treatment of Kras-mutant mice with anti-ST2 antibody resulted in depletion of activated Tregs in lung tumor while leaving Tregs in secondary lymphoid organs intact. Also, localized Tregs depletion led to a significant reduction in lung tumor burden. Immune response after Tregs depletion in tumors showed restoration of NK cell activity and enhanced Th1 activity, with increased CD8 cytotoxic T cell response. In addition, we found that the M2 macrophage signature in lung tumors was suppressed upon Tregs depletion, accompanied by upregulation of surface expression of MHC-II molecules and reduced expression of , and . These data suggest that therapeutic strategies targeting activated Tregs in lung cancer have the potential to restrain tumor progression by enhancing anti-tumor immunity.

Immune checkpoint inhibitors against PD-1/PD-L1 yield improved survival rates of KRAS-mutant NSCLC patients, who conferred a poor prognosis without effective targeted therapy until now. Yet, the underlying association between KRAS mutations and immune responses remains unclear. We performed an integrated analysis of the data from publicly available repositories and from clinical center cohorts to explore the association between KRAS mutation status and tumor immunity-associated features, including PD-L1 expression, CD8 tumor-infiltrating lymphocytes (TILs) and tumor mutational burden (TMB). Our results revealed that KRAS mutations are correlated with an inflammatory tumor microenvironment and tumor immunogenicity, resulting in superior patient response to PD-1/PD-L1 inhibitors. Meanwhile, three-pool analysis further confirmed that KRAS-mutant NSCLC patients show remarkable clinical benefit from anti-PD-1/PD-L1 immunotherapy. In addition, a KRAS-mutant lung adenocarcinoma mouse model was established to estimate the relative efficacy of anti-PD-L1 monoclonal antibody monotherapy or combination treatment with docetaxel versus docetaxel alone. Most surprisingly, we found that PD-L1 blockade combined with docetaxel did not promote an anti-tumor response. These findings uncover that PD-1/PD-L1 blockade monotherapy may be the optimal therapeutic schedule in NSCLC patients harboring KRAS mutations.

OBJECTIVES:The efficacy of anti- programmed cell death 1 (PD-1)/PD-1 ligand (PD-L1) immune checkpoint inhibitors remains controversial in patients with KRAS mutation. In addition, whether and how KRAS gene and its mutant subtypes might influence immunity has not been clarified yet. Here we examine some important biomarkers for the efficacy of immunotherapy in specific KRAS subtypes. MATERIALS AND METHODS:We conducted a bioinformatics analysis on somatic mutations data, transcriptome sequencing data and proteomic data from The Cancer Genome Atlas (TCGA) database. CIBERSORT was used to provide an estimation of the abundances of immune cells using gene expression data. RESULTS:From a cohort of 567 patients with lung adenocarcinoma (LUAD) based on TCGA, the overall mutation rate of KRAS was 26.29 %, including KRAS/TP53 co-mutation rate of 9.7 %. We observed increased Tumor mutation burden (TMB) in KRAS mutant group compared with wild type, while no difference in PD-L1 expression and immune cell infiltration. More importantly, TP53 and KRAS/TP53 co-mutation group not only significantly increased tumor mutation burden, but also had higher PD-L1 protein level and immune cell infiltration. We further focused on influence of KRAS mutant subtype on immune biomarker. The most prevalent mutant subtype of KRAS in lung adenocarcinoma was G12C(9.88 %,56/567), followed by G12 V(5.82 %,33/567), G12D(3.00 %,17/567), G12A(3.00 %,17/567), respectively. Among them, G12D mutation appeared to be a special mutant subtype with an obviously lower TMB. This low mutation load was more significant when co-mutation with TP53. Besides, our results also revealed significantly decreased expressions of PD-L1 protein level and immune cell infiltration (activated CD4 memory T cell, helper T cell, M1 macrophage and NK cell) in KRAS G12D/TP53 mutant group. CONCLUSION:KRAS G12D/TP53 co-mutation drives immune suppression and might be a negative predictive biomarker for anti-PD-1/PD-L1 immune checkpoint inhibitors in patients with lung adenocarcinoma.

PURPOSE:Mutated KRAS oncogene in exhaled breath condensate (EBC) can be a genetic marker of non-small cell lung cancer (NSCLC). However, a possibility of inhomogeneous distribution in cancer tissue and intratumor heterogeneity of KRAS mutation may decrease its significance. We investigated a status of KRAS point mutation and its sequence at codon 12 in 51 NSCLC patients after tumor resection. The comparison of KRAS mutation status between EBC-DNA and cancer tissue was performed in 19 cases. METHODS:Five cancer tissue samples from disparate tumor regions and one from normal lung were harvested at surgery. EBC was collected for DNA analysis the previous day. KRAS point mutations at codon 12 were detected using mutant-enriched PCR technique and pyrosequenced. RESULTS:Forty-six cancers revealed concordance of KRAS mutation status: 27 contained mutated KRAS and 19 had only wild KRAS. Five NSCLCs revealed inhomogeneous distribution of KRAS mutation. Two different mutations were found in 14 NSCLCs and the most frequent one was G12D and G12V (n = 8). No mutated KRAS was found in normal lung. The concordance ratios of KRAS sequence in codon 12 between EBC-DNA and cancer were 18/19 for NSCLC patients and 11/12 for KRAS mutation positive NSCLC. CONCLUSIONS:Intratumor heterogeneity and inhomogeneous distribution of KRAS point mutation in codon 12 in cancer tissue can occur in NSCLCs. There was a high accordance between KRAS mutation status in EBC-DNA and cancer tissue in NSCLC patients what suggests usefulness of monitoring KRAS mutation in EBC-DNA as a biomarker of NSCLC.

OBJECTIVES:Non-small cell lung cancer (NSCLC) is a heterogeneous disease with unique combinations of somatic molecular alterations in individual patients, as well as significant differences in populations across the world with regard to mutation spectra and mutation frequencies. Here we aim to describe mutational patterns and linked clinical parameters in a population-based NSCLC cohort. MATERIALS AND METHODS:Using targeted resequencing the mutational status of 82 genes was evaluated in a consecutive Swedish surgical NSCLC cohort, consisting of 352 patient samples from either fresh frozen or formalin fixed paraffin embedded (FFPE) tissues. The panel covers all exons of the 82 genes and utilizes reduced target fragment length and two-strand capture making it compatible with degraded FFPE samples. RESULTS:We obtained a uniform sequencing coverage and mutation load across the fresh frozen and FFPE samples by adaption of sequencing depth and bioinformatic pipeline, thereby avoiding a technical bias between these two sample types. At large, the mutation frequencies resembled the frequencies seen in other western populations, except for a high frequency of KRAS hotspot mutations (43%) in adenocarcinoma patients. Worse overall survival was observed for adenocarcinoma patients with a mutation in either TP53, STK11 or SMARCA4. In the adenocarcinoma KRAS-mutated group poor survival appeared to be linked to concomitant TP53 or STK11 mutations, and not to KRAS mutation as a single aberration. Similar results were seen in the analysis of publicly available data from the cBioPortal. In squamous cell carcinoma a worse prognosis could be observed for patients with MLL2 mutations, while CSMD3 mutations were linked to a better prognosis. CONCLUSION:Here we have evaluated the mutational status of a NSCLC cohort. We could not confirm any survival impact of isolated driver mutations. Instead, concurrent mutations in TP53 and STK11 were shown to confer poor survival in the KRAS-positive adenocarcinoma subgroup.

Lung cancer is the leading cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) accounts for 80%-85% of all patients with lung cancer, the majority of patients with lung cancer at the time of diagnosis is in the advanced stage. The development of target therapy based on has changed the mode of treatment in patients with advanced NSCLC. In NSCLC, epidermal growth factor receptor mutation (EGFR) fusion with echinoderm microtubule-associated protein-like4-anaplastic lymphoma kinase (EML4-ALK) has been shown to be a powerful biomarker. It is well known that KRAS is also NSCLC one of the most common mutations in oncogenes, although more than 20 years ago KRAS mutation was found in NSCLC. At present, although there are many drugs used to treat NSCLC patients with KRAS mutation, there is no selective or specific inhibitor for the direct elimination of KRAS activity. NSCLC patients with KRAS mutation have poor responsiveness to most systemic therapy. However, individualized therapy for activated signaling pathways with targeted drugs has a good effect on the prognosis of NSCLC patients with KRAS mutation. In addition, the prognostic and predictive role of KRAS mutation in NSCLC remains unclear. In this review, we focus on the research progress of NSCLC with KRAS mutation, including molecular biology, clinicopathological features, prognosis and prediction of KRAS mutation, which will help to improve the understanding of NSCLC in KRAS mutation.
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OBJECTIVES:Concurrent genetic mutations are prevalent in KRAS-mutant non-small cell lung cancer (NSCLC) and may differentially influence patient outcomes. We sought to characterize the effects of KRAS mutation subtypes and concurrent pathogenic mutations on overall survival (OS) and PD-L1 expression, a predictive biomarker for anti-PD-1/PD-L1 immunotherapy. MATERIALS AND METHODS:We retrospectively identified patients with KRAS-mutant NSCLC at a single institution and abstracted clinical, molecular, and pathologic data from electronic health records. Cox regression and multinomial logistic regression were used to determine how KRAS mutation subtypes and concurrent pathogenic mutations are associated with OS and tumor PD-L1 expression, respectively. RESULTS:A total 186 patients were included. Common KRAS mutation subtypes included G12C (35%) and G12D (17%). Concurrent pathogenic mutations were identified in TP53 (39%), STK11 (12%), KEAP1 (8%), and PIK3CA (4%). On multivariable analysis, KRAS G12D mutations were significantly associated with poor OS (hazard ratio [HR] 2.43, 95% confidence interval [CI] 1.15-5.16; P = 0.021), as were STK11 co-mutations (HR 2.95, 95% CI 1.27-6.88; P = 0.012). Compared to no (<1%) PD-L1 expression, KRAS G12C mutations were significantly associated with positive yet low (1-49%) PD-L1 expression (odds ratio [OR] 4.94, 95% CI 1.07-22.85; P = 0.041), and TP53 co-mutations with high (≥50%) PD-L1 expression (OR 6.36, 95% CI 1.84-22.02; P = 0.004). CONCLUSION:KRAS G12D and STK11 mutations confer poor prognoses for patients with KRAS-mutant NSCLC. KRAS G12C and TP53 mutations correlate with a biomarker that predicts benefit from immunotherapy. Concurrent mutations may represent distinct subsets of KRAS-mutant NSCLC; further investigation is warranted to elucidate their role in guiding treatment.