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Aims: Host immunity influences cancer progression and therapeutic response. We investigated the potential of tumour‐infiltrating lymphocytes (TILs) around ductal carcinoma in situ (DCIS) in predicting recurrence and progression. Methods and results: CD4, CD8, programmed cell death 1 (PD‐1) and programmed cell death ligand 1 (PD‐L1) expression in DCIS from 198 patients was determined by immunohistochemistry. We correlated disease‐free survival (DFS), clinicopathological parameters and biomarker expression with TIL density and CD4/CD8 ratio. High TIL density was associated with high nuclear grade (P < 0.001), DCIS PD‐L1 expression (P = 0.008), TIL PD‐L1 expression (P < 0.001), oestrogen (ER) negativity (P < 0.001), progesterone (PR) negativity (P < 0.001), human epidermal growth factor receptor 2 (HER2) positivity (P = 0.002) and triple negativity (P = 0.001). TIL PD‐L1 expression was associated with triple‐negative DCIS (P = 0.028). TIL density was associated with molecular subtypes (P < 0.001). High CD4+ T cell density was associated with high nuclear grade (P = 0.001), microinvasion (P = 0.037), ER negativity (P < 0.001), PR negativity (P = 0.001), HER2 positivity (P = 0.004), triple negativity (P = 0.023) and PD‐L1 expression in TILs (P < 0.011). High CD4/CD8 ratio was associated with PD‐L1 expression in DCIS (P = 0.035) and TILs (P < 0.001). DCIS with higher TIL density disclosed worse DFS (P = 0.012) and was affirmed with multivariate analysis [95% confidence interval (CI) = 1.109–2.554, hazard ratio (HR) = 1.683, P = 0.014]. Poorer DFS for ipsilateral invasive recurrence was found for DCIS with higher CD4+ T cell density (P = 0.006) or CD4/CD8 ratio (P = 0.02), confirmed by multivariate analysis for the former (95% CI = 1.369–10.196, HR = 3.736, P = 0.01) and latter (95% CI = 1.311–7.935, HR = 3.225, P = 0.011). Conclusion: DCIS with higher TIL density was associated with poorer prognostic parameters and predicted recurrence, while both CD4+ T cell density and CD4/CD8 ratio were associated with both recurrence and ipsilateral invasive recurrence. [ABSTRACT FROM AUTHOR]

Purpose: HER2 -altered non-small-cell lung cancer (NSCLC) represents a diverse subgroup, including mutations, amplifications, and overexpression. However, HER2 exon 20 insertion mutations are emerging as a distinct molecular subtype with expanding therapeutic options. We describe the molecular epidemiology and genomic features of HER2 -altered NSCLC in an Asian tertiary cancer center., Methods: We identified patients with HER2 -mutated NSCLC in our institutional database, collating clinicopathological features and treatment outcomes. The genomic landscape of human epidermal growth factor receptor 2 ( HER2 )-mutated NSCLC was further evaluated using whole-exome sequencing (WES) data from combined local and publicly available data sets. HER2 amplification and overexpression as selection biomarkers in NSCLC were further interrogated using HER2 immunohistochemistry and correlations with WES and RNA sequencing data., Results: Among 1,252 patients with consecutive lung adenocarcinoma undergoing routine next-generation sequencing, the prevalence of HER2 mutations was 3.1%-exon 20 insertion mutations comprised 2.7%. We examined the clinicopathological features in 55 patients with HER2 -mutated NSCLC comprising 40 exon 20 insertion and 15 nonexon 20 insertion mutations. The most common exon 20 insertion mutation was HER2 Y772&#95;A775dup in 30 (75%), followed by HER2 G776delinsVC in five patients (13%). There were limited responses to HER2-directed therapies apart from trastuzumab-deruxtecan, and no responses were seen with immunotherapy monotherapy. Evaluating the genomics features of HER2 exon 20 insertion mutations using WES data revealed low tumor mutational burden (TMB), low incidence of cancer driver comutations, and a predominance of aging mutational signature-similar to EGFR -mutated tumors. In contrast, uncommon (or nonexon 20 insertion) HER2 -mutated tumors resembled EGFR wild-type tumors with higher TMB, higher frequency of cancer driver comutations, and greater presence of smoking and APOBEC mutational signature. Finally, in evaluating HER2 immunohistochemistry in all lung adenocarcinoma, there was significant discordance comparing different scoring systems and poor correlation with HER2 RNA expression and HER2 amplification., Conclusion: The incidence of HER2 mutations is 3.1% in East Asian nonsquamous NSCLC. HER2 exon 20 insertion-mutated tumors appear genomically distinct from uncommon (nonexon 20 insertion) HER2 mutations, the latter demonstrating higher TMB, co-occurring drivers, and predominant nonaging mutational signature. The therapeutic implications of the genomic and clinical features of HER2 -mutated NSCLC warrant further investigation.

Introduction: Although immune checkpoint inhibitors (ICIs) have dramatically improved outcomes for nononcogene-addicted NSCLC, monotherapy with programmed cell death protein-1 (PD1) inhibition has been associated with low efficacy in the EGFR-mutant setting. Given the potential for synergism with combination checkpoint blockade, we designed a trial to test the activity of combination nivolumab (N)-ipilimumab (NI) in EGFR-mutant NSCLC., Methods: This is a randomized phase 2 study (NCT03091491) of N versus NI combination in EGFR tyrosine kinase inhibitor (TKI)-resistant NSCLC, with crossover permitted on disease progression. The primary end point was the objective response rate, and the secondary end points included progression-free survival, overall survival, and safety of ICI after EGFR TKI., Results: Recruitment ceased owing to futility after 31 of 184 planned patients were treated. A total of 15 patients received N and 16 received NI combination. There were 16 patients (51.6%) who had programmed death-ligand (PDL1) 1 greater than or equal to 1%, and 15 (45.2%) harbored EGFR T790M. Five patients derived clinical benefits from ICI with one objective response (objective response rate 3.2%), and median progression-free survival was 1.22 months (95% confidence interval: 1.15-1.35) for the overall cohort. None of the four patients who crossed over achieved salvage response by NI. PDL1 and tumor mutational burden (TMB) were not able to predict ICI response. Rates of all grade immune-related adverse events were similar (80% versus 75%), with only two grade 3 events., Conclusions: Immune checkpoint inhibition is ineffective in EGFR TKI-resistant NSCLC. Whereas a small subgroup of EGFR-mutant NSCLC may be immunogenic and responsive to ICI, better biomarkers are needed to select appropriate patients., (© 2022 by the International Association for the Study of Lung Cancer.)

Purpose: Despite the established role of EGFR tyrosine kinase inhibitors (TKIs) in EGFR -mutated NSCLC, drug resistance inevitably ensues, with a paucity of treatment options especially in EGFR T790M -negative resistance., Experimental Design: We performed whole-exome and transcriptome analysis of 59 patients with first- and second-generation EGFR TKI-resistant metastatic EGFR -mutated NSCLC to characterize and compare molecular alterations mediating resistance in T790M-positive (T790M + ) and -negative (T790M - ) disease., Results: Transcriptomic analysis revealed ubiquitous loss of adenocarcinoma lineage gene expression in T790M - tumors, orthogonally validated using multiplex IHC. There was enrichment of genomic features such as TP53 alterations, 3q chromosomal amplifications, whole-genome doubling and nonaging mutational signatures in T790M - tumors. Almost half of resistant tumors were further classified as immune hot , with clinical outcomes conditional on immune cell-infiltration state and T790M status. Finally, using a Bayesian statistical approach, we explored how T790M - and T790M + disease might be predicted using comprehensive genomic and transcriptomic profiles of treatment-naïve patients., Conclusions: Our results illustrate the interplay between genetic alterations, cell lineage plasticity, and immune microenvironment in shaping divergent TKI resistance and outcome trajectories in EGFR -mutated NSCLC. Genomic and transcriptomic profiling may facilitate the design of bespoke therapeutic approaches tailored to a tumor's adaptive potential., (©2021 The Authors; Published by the American Association for Cancer Research.)