Multi-omics analyses reveal distinct molecular characteristics and transformation mechanisms of stage I-III micropapillary lung adenocarcinoma

The micropapillary (MIP) pattern is a high-grade histological subtype of lung adenocarcinoma (LUAD) with poor prognosis. In this study, surgically resected tumor samples from 101 patients with stage I-III MIP-LUAD (MIP >= 30%) were microdissected to separate MIP components from non-MIP components, all of which underwent RNA and DNA whole-exome sequencing (WES). The genomic and transcriptomic landscapes of MIP and non-MIP components within MIP-enriched tumor tissues demonstrated remarkable similarities, notably marked by high epidermal growth factor receptor (EGFR) alteration frequencies. However, when compared to MIP-na & iuml;ve LUAD tissues, MIP components showed higher chromosomal instability and revealed 18 enriched alterations, encompassing EGFR mutations, EGFR amplifications, and CDKN2A/CDKN2B deletions, which all linked to upregulation of cell proliferation pathways and downregulation of immune pathways. Shared mutations were observed in 97.8% (91/93) of patients with paired DNA WES data for MIP and non-MIP components within the same tissues, suggesting a common origin. The recurrence-free survival analysis identified MACF1, PCLO, ADGRV1, and Fanconi Anemia pathway mutations as negative indicators. In all, we conducted an in-depth analysis of the molecular characteristics and transformation mechanisms of MIP-LUAD, employing microdissection techniques to investigate the genomic and transcriptomic levels within a substantial cohort, providing insights for precision medicine of this aggressive cancer subtype. (c) 2025 The Pathological Society of Great Britain and Ireland.