Cancer Med. 2026 Apr;15(4):e71833. doi: 10.1002/cam4.71833.

ABSTRACT

OBJECTIVES: This study aims to elucidate the role of FGFR1 in activating the Wnt/β-catenin signaling pathway and the underlying mechanisms by which it promotes malignant progression in lung squamous cell carcinoma (LUSC). By integrating multi-omics analysis with functional experiments, the clinical heterogeneity of FGFR1 amplification, signaling crosstalk, and their regulatory networks governing tumor phenotypes were revealed.

METHODS: Using TCGA data (n = 490), we analyzed the relationship between FGFR1 copy number variation (CNV) and mRNA expression in LUSC, and validated the correlation with protein expression in a clinical cohort (n = 38). GSEA and single-gene GSEA were performed to identify signaling pathways associated with high FGFR1 expression. The interaction between FGFR1 and the Wnt/β-catenin pathway was investigated by immunohistochemistry, immunofluorescence, stable cell lines, Western blot, qPCR, and functional assays.

RESULTS: FGFR1 amplification correlated with increased mRNA and protein expression. The top 25% FGFR1 high-expression group enriched Wnt/β-catenin, PI3K-Akt, and cAMP pathways. Mechanistically, FGFR1 promoted β-catenin nuclear accumulation and enhanced β-catenin signaling through PKA-associated phosphorylation and Akt/GSK3β-related regulation of β-catenin stability, and these effects were attenuated by AKT inhibition. CTNNB1 knockdown significantly inhibited proliferation, migration, invasion, and tumor growth of LUSC cells.

CONCLUSIONS: Our findings indicate that FGFR1 activates Wnt/β-catenin signaling through coordinated regulation of β-catenin phosphorylation, stability, and subcellular localization, thereby promoting malignant progression in LUSC. These results provide a rationale for targeting the FGFR1-Wnt/β-catenin axis as a potential therapeutic strategy.

PMID:41998829 | DOI:10.1002/cam4.71833

Cell Rep Med. 2026 Apr 10:102741. doi: 10.1016/j.xcrm.2026.102741. Online ahead of print.

ABSTRACT

Combined small-cell lung cancer (cSCLC) is an aggressive subtype of SCLC with mixed histologic components. Despite heterogeneity and poorer prognosis than de novo SCLC, cSCLC is managed as SCLC because molecular insight into biology, lineage plasticity, and tumor microenvironment (TME) is limited. We perform spatial whole-exome sequencing, spatial transcriptomics, and single-nucleus RNA sequencing across 19 treatment-naive cSCLC tumors. Different histologic components share a monoclonal origin, whereas divergence associates with distinct mutation and copy-number alteration patterns. Our results define spatially exclusive or interspersed tumor domains with distinct TME and immune landscapes; fibroblast-rich boundaries enriched for an aggressive fibroblast subtype may shape TME and treatment responses. We identify lineage plasticity, including adenocarcinoma-to-SCLC transdifferentiation and SCLC-subtype coexistence, and develop cSCLC Detector, a sensitive mutation-based assay improving cSCLC detection in tissue and liquid biopsies. These findings illuminate cSCLC evolution and heterogeneity, underscoring the need for tailored diagnostic and therapeutic strategies for this aggressive subtype.

PMID:41966692 | DOI:10.1016/j.xcrm.2026.102741