Galectin-7 as a biomarker for aggressiveness and poor prognosis in thymic epithelial tumors

To identify molecular determinants of tumor aggressiveness in TETs and to elucidate their functional roles and underlying mechanisms in tumor progression.

We performed proteomic profiling using data-independent acquisition mass spectrometry on 40 TET samples and their paired adjacent normal tissues to explore potential molecular differences. TETs were stratified into high-risk (WHO types B2, B3, and thymic carcinoma) and low-risk (types A, AB, and B1) groups based on histological classification. Gene set enrichment analysis (GSEA) was applied to the proteomic data to delineate pathways enriched in high-risk tumors. A validation cohort comprising 164 TET patients, along with 6 non-TET controls, was analyzed to assess Galectin-7 expression by immunohistochemistry and to evaluate its prognostic value. To further explore the biological role of Galectin-7, functional assays were performed in Tc1889 cells following Galectin-7 overexpression.

Proteomic analysis revealed Galectin-7 as a highly upregulated protein in high-risk TETs. GSEA analysis identified enrichment of mitochondrial and extracellular matrix-related pathways in high-risk tumors. Immunohistochemistry showed Galectin-7 expression in 82 % of high-risk TETs and only 13 % of low-risk TETs (p < 0.001), with higher expression correlating with advanced tumor stage and reduced progression-free survival. Functional assays demonstrated that Tc1889 cells with Galectin-7 overexpression exhibited enhanced proliferation and invasion. Additionally, MAPK signaling pathway activation was observed in Galectin-7-overexpressing cells.

Galectin-7 is a potential biomarker for aggressive TETs, with expression levels associated with features of poor prognosis. These findings provide insight into TET biology and support further exploration of Galectin-7 in tumor stratification and therapeutic research.