Introduction: Esophageal cancer is a deadly disease with high mortality. Treatment with chemotherapy, radiation, and surgery continues to leave many patients with disease progression and recurrence. Novel treatments are needed for this patient population. The development of molecular markers are important for identifying therapeutic targets, as well as prognosis.

Areas covered: This review evaluates three molecular markers in esophageal cancer: HER2, PD-L1, and MSI. The fundamentals of these markers, diagnosis, and rates of occurrence in esophageal cancer are explored. The prognostic potential of these markers is based on existing literature as well as application in clinical trials. Key trial findings pertaining to the therapeutic targets for HER2 and PD-1 as well as the role of MSI are discussed.

Expert commentary: Molecular markers are changing the practice for esophageal cancer. Therapeutic targeting for HER2 and PD-L1 have shown positive results in recent clinical trials. Trials evaluating immunotherapy as first-line agents are currently underway.

导读：食管癌是一种致死性疾病，死亡率很高。化疗、放疗和手术治疗继续使许多患者出现疾病进展和复发。该患者群体需要新的治疗方法。分子标志物的开发对于确定治疗靶点和预后很重要。

涵盖的领域：本综述评估了食管癌的三种分子标志物：HER2、PD-L1 和 MSI。探索了这些标志物、诊断和食管癌发生率的基本原理。这些标志物的预后潜力基于现有文献以及临床试验中的应用。讨论了与 HER2 和 PD-1 的治疗靶点以及 MSI 的作用有关的主要试验结果。

专家评论：分子标志物正在改变食道癌的治疗方法。HER2 和 PD-L1 的治疗靶向在最近的临床试验中显示出积极的结果。评估免疫疗法作为一线药物的试验目前正在进行中。