KEY POINTS
- Esophageal squamous-cell carcinoma was induced in female C57BL/6 mice using 4-nitroquinoline-1-oxide. Single-cell sequencing included 14 mice and 113,073 cells, while spatial transcriptomics included 15 mice and 3,946 spatial spots across untreated, radiotherapy, chemoradiotherapy, and immunoradiotherapy groups.
- Mouse radiotherapy was delivered as 8 Gy × 3 using 6-MV photons. Combination groups received either 5-fluorouracil 30 mg/kg three times weekly for six doses or anti-PD-1 treatment 10 mg/kg twice weekly for four doses; tissues were collected 21 days after treatment began.
- All three radiation-containing interventions reduced components associated with an immunosuppressive microenvironment, including regulatory T cells, PD-1-positive CD4 T cells, and Col12a1-positive cancer-associated fibroblasts. Radiotherapy and chemoradiotherapy also increased IL-17-producing CD4 T-cell populations.
- Chemoradiotherapy had the clearest effect on malignant epithelial programs. It reduced a poorly differentiated Lamc2-high epithelial state and decreased angiogenesis, hypoxia, glycolysis, HIF-1, and TGF-β-related transcriptional programs relative to untreated tumours, radiotherapy alone, and immunoradiotherapy.
- Chemoradiotherapy also reduced Hbegf-positive macrophages and their inferred interaction with EGFR-positive epithelial cells. Human immunohistochemistry similarly showed lower LAMC2 expression after chemoradiotherapy than after surgery alone or immunoradiotherapy.
- Immunoradiotherapy preferentially enriched a transitional Ccl5-positive, Eomes-positive CD8 T-cell population with chemokine and effector-memory features. Spatial mapping localized these cells within treated tumour tissue, and human immunofluorescence showed corresponding CCL5-positive and EOMES-positive CD8 infiltration after radioimmunotherapy.
- Human validation included only 14 surgical specimens: five untreated surgery cases, five after neoadjuvant chemoradiotherapy, and four after neoadjuvant immunoradiotherapy. Both neoadjuvant groups received 41.4 Gy; chemoradiotherapy used paclitaxel plus platinum, while immunoradiotherapy used two cycles of a PD-1 antibody.
- The study did not test whether LAMC2 suppression, macrophage reprogramming, or CCL5-positive CD8 enrichment predicts pathological response, recurrence, survival, or treatment toxicity. Treatment regimens also differed between mouse and human cohorts, and the human sample was too small for clinical comparisons.
CLINICAL TAKEAWAY
The study provides a mechanistic map suggesting that chemoradiotherapy acts predominantly through malignant epithelial and macrophage programs, whereas immunoradiotherapy preferentially expands an effector CD8 T-cell state. These findings are useful for biomarker and combination-therapy development but are not evidence that either regimen is clinically superior.