Single-cell analysis identifies a stemness-associated tumor cell subpopulation and develops a prognostic scoring model in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) exhibits marked heterogeneity and poor prognosis, but the contribution of stemness‑related tumor cells remains unclear. Using single‑cell RNA sequencing, we identified eight tumor subpopulations in ESCC, among which one cluster displayed prominent stem‑like and proliferative features with high expression of MKI67, STMN1, and UBE2C. Based on its marker genes, we established a stemness‑associated scoring model (SASM). Validation in independent TCGA and GSE53624 cohorts confirmed that higher SASM scores predicted shorter overall survival and reduced immune infiltration, particularly of CD8⁺ T cells. SASM scores were positively correlated with tumor mutational burden (TMB), and patients with high SASM and low TMB exhibited the poorest outcomes. Further analysis identified TFDP1 as a key gene associated with SASM and adverse prognosis, which was upregulated in tumor tissues and promoted ESCC cell proliferation in vitro. Overall, our study delineates stemness‑related tumor heterogeneity in ESCC, proposes a prognostic scoring system with immunological relevance, and highlights TFDP1 as a potential therapeutic target.