The radioresistance of oesophageal squamous cell carcinoma (OSCC) is a critical factor leading to a poor prognosis among patients. The expression of PBX1 is abnormally high in a broad range of human tissues, and this gene plays a key role in tumour proliferation. This research intended to explore the radiosensitization of OSCC by silencing PBX1. The OSCC cell lines KYSE450 and KYSE150 were subjected to PBX1 silencing and/or irradiation (IR). Cell proliferation, colony formation, and apoptosis were tested to evaluate the radiosensitization ability of PBX1 silencing. The levels of STAT3 and p-STAT3 in the OSCC cells were tested by Western blotting. Furthermore, KYSE150 cells with or without PBX1 silencing were xenografted into nude mice with or without radiation exposure. Concomitant PBX1 silencing and IR can obviously suppress growth and enhance radiosensitivity in OSCC cells and xenografts. Moreover, the downregulation of PBX1 inhibits the expression of STAT3 and p-STAT3. The downregulation of PBX1 may increase radiosensitivity in OSCC cells and xenografts via the PBX1/STAT3 pathway. Our findings demonstrate that PBX1 may be a potential target for promoting the effect of radiation therapy in OSCC patients.

食管鳞状细胞癌（OSCC）的放射抵抗是导致患者预后不良的关键因素。 PBX1在多种人体组织中表达异常高，该基因在肿瘤增殖中发挥着关键作用。本研究旨在探讨通过沉默PBX1对OSCC的放射增敏作用。对 OSCC 细胞系 KYSE450 和 KYSE150 进行 PBX1 沉默和/或照射 (IR)。通过测试细胞增殖、集落形成和凋亡来评估PBX1沉默的放射增敏能力。通过Western blotting检测OSCC细胞中STAT3和p-STAT3的水平。此外，将有或没有PBX1沉默的KYSE150细胞异种移植到有或没有辐射暴露的裸鼠中。 PBX1 沉默和 IR 联合使用可以明显抑制 OSCC 细胞和异种移植物的生长并增强放射敏感性。此外，PBX1的下调会抑制STAT3和p-STAT3的表达。 PBX1 的下调可能通过 PBX1/STAT3 途径增加 OSCC 细胞和异种移植物的放射敏感性。我们的研究结果表明，PBX1可能是促进口腔鳞癌患者放射治疗效果的潜在靶点。