Human leukocyte antigen class I on peripheral blood mononuclear cells as a non-invasive biomarker for esophageal cancer

Esophageal cancer (EC) is a common malignant cancer threatening people's health. There are no universally accepted parameters for its early diagnosis. The aim of this study was to observe the expression of human leukocyte antigen class I (HLA-I) on peripheral blood mononuclear cells (PBMCs) of EC patients and in individuals of high-incidence area of EC so as to evaluate the feasibility of using this parameter as a potential non-invasive biomarker for the early diagnosis of EC. The present study enrolled 58 pathological confirmed EC patients, 46 patients with benign esophageal disease, and 65 healthy volunteers. Expression levels of HLA-I protein and mRNA on PBMCs were determined by flow cytometry and quantitative reverse transcriptase polymerase chain reaction, respectively. Then, 181 volunteers from Lijiadian, a village with high morbidity of EC, and 153 age- and gender-matched health volunteers were involved in this study to observe HLA-I expressions in individuals of high-incidence area of EC. Compared with benign esophageal disease and health volunteers, the expressions of HLA-I protein and mRNA on PBMCs of EC patients are significantly decreased, especially in patients with stage III and IV EC, but was not influenced by patient's age and gender. Furthermore, individuals of high-incidence area of EC also show downregulated HLA-I protein, but not mRNA, expression on PBMCs. Altogether, HLA-I expression on PBMCs of EC patients and individuals from high-incidence area of EC is downregulated, and this parameter might be used as a potential predictor of EC.