This study systematically reveals that lung adenocarcinomas with mucinous components possess distinct clinical, pathological, genomic, and immune microenvironment features, and confirms their poor response to immunotherapy and KRASG12C inhibitors, providing crucial evidence for precision treatment strategies.
Literature Overview
This article, 'Lung adenocarcinomas with mucinous histology: clinical, genomic, and immune microenvironment characterization and outcomes to immunotherapy-based treatments and KRASG12C inhibitors,' published in the journal Annals of Oncology: official journal of the European Society for Medical Oncology, reviews and summarizes differences between lung adenocarcinomas with mucinous components (LUADMuc) and non-mucinous lung adenocarcinomas (LUADnon-muc) in terms of clinicopathological characteristics, genomic alterations, immune microenvironment, and responses to immune checkpoint inhibitors (ICI) and KRASG12C inhibitors. Based on multi-center cohorts and TCGA data, the study systematically analyzes the molecular profiles and treatment outcomes of LUADMuc, revealing lower PD-L1 expression, tumor mutation burden, and immune cell infiltration, along with suboptimal responses to ICI and targeted therapies. The study emphasizes the important prognostic and predictive value of histological subtypes in precision lung cancer treatment. The paragraph is coherent and logical, ending with a Chinese period.Background Knowledge
Lung adenocarcinoma is the most common histological subtype of non-small cell lung cancer, with approximately 3–10% exhibiting mucinous components, classified by the World Health Organization (WHO) as mucinous adenocarcinoma. These tumors are typically TTF-1 negative or weakly positive, more common in never-smokers, and frequently harbor KRAS mutations, particularly KRASG12D. Although targeted and immunotherapies have significantly improved outcomes for non-mucinous lung adenocarcinoma, the response of mucinous variants to current treatments remains unclear. Previous studies suggest these tumors may exhibit an immunologically 'cold' microenvironment, implying limited efficacy of immune checkpoint inhibitors. However, large-scale, multi-omics integrated analyses validating their unique biological behaviors and treatment outcomes are lacking. Moreover, with the clinical application of KRASG12C inhibitors, it has become imperative to determine whether this subtype benefits from such therapies. Therefore, systematically characterizing the molecular and immune features of LUADMuc and evaluating their sensitivity to current standard treatments hold significant clinical implications.
Research Methods and Experiments
The study included 4,082 lung adenocarcinoma patients from five international medical centers and the TCGA PanCancer Atlas database, classified according to WHO criteria into those with mucinous components (LUADMuc) and non-mucinous types (LUADnon-muc). Genomic alterations were analyzed using next-generation sequencing (NGS), and immune cell densities of CD8+, PD-1+, FOXP3+ cells in the tumor microenvironment were assessed via multiplex immunofluorescence. Transcriptomic data were obtained from the TCGA database and subjected to unsupervised clustering analysis. Treatment outcomes included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) for patients receiving ICI monotherapy, chemotherapy combined with ICI, or KRASG12C inhibitors. Multivariable Cox regression models were used to adjust for confounding factors. Subgroup analyses further distinguished pure mucinous from mixed mucinous adenocarcinomas and evaluated the impact of mutations in genes such as STK11, KEAP1, and SMARCA4.Key Conclusions and Perspectives
Research Significance and Prospects
This study provides the first large-scale confirmation that lung adenocarcinomas with mucinous components represent a distinct molecular subtype, whose immunologically 'cold' microenvironment and specific genomic alterations lead to poor response to immunotherapy. These findings suggest that mucinous components should be considered an independent prognostic and predictive factor in clinical practice, particularly warranting caution when considering ICI treatment. For patients with KRASG12C mutations, although targeted therapy offers some clinical benefit, overall survival remains short, indicating the need to explore combination strategies to overcome resistance.
Future studies should further dissect the intratumoral heterogeneity of LUADMuc, particularly the evolutionary pathways and microenvironmental regulatory mechanisms of pure versus mixed subtypes. Developing novel therapies targeting mucinous-specific antigens or reprogramming the microenvironment—such as bispecific antibodies or metabolic modulators—may overcome current therapeutic bottlenecks. Additionally, validating these findings in more prospective cohorts will help optimize personalized treatment approaches.
Conclusion
This study systematically reveals lung adenocarcinomas with mucinous components (LUADMuc) as a distinct clinical and molecular subtype, characterized by minimal smoking history, low PD-L1 expression, low tumor mutation burden, and a specific mutational profile (e.g., KRASG12D, GNAS, STK11). Compared to non-mucinous lung adenocarcinoma, LUADMuc exhibits significantly reduced tumor-infiltrating lymphocytes, resulting in an immunologically 'cold' microenvironment that leads to markedly diminished efficacy of immune checkpoint inhibitors, whether used alone or in combination with chemotherapy. Although KRASG12C inhibitors can induce partial responses, overall survival remains significantly shorter. The study further identifies biological and prognostic differences between pure and mixed mucinous subtypes, highlighting the impact of histological heterogeneity on treatment decisions. These findings underscore the necessity of considering histological subtypes in precision lung cancer therapy, providing critical evidence for developing specific treatment strategies for LUADMuc, and calling for independent stratification of these patients in future clinical trial designs。
