RESUMO
To evaluate the association of the plasma riboflavin level in Kazak esophageal cancer patients and their riboflavin transporter (C20orf54) gene statuses. Plasma riboflavin levels were detected by high performance liquid chromatography in Kazak patients with esophageal squamous cell carcinoma (ESCC) and healthy controls. C20orf54 mRNA and protein expression were analyzed by real-time fluorogenic quantitative polymerase chain reaction and immunohistochemistry in samples from 61 ESCC patients consisting of both tumor and normal tissue, respectively. C20orf54 mRNA expression was decreased in ESCC (0.279 ± 0.102) than in normal counterpart tissue (0.479 ± 0.287; P = 0.049) significantly. Tumors exhibited low C20orf54 protein expression (42.6, 26.2, 18.0 and 13.1% for no C20orf54 staining, weak staining, medium staining and strong staining, respectively), which was significantly lower than that in the normal mucous membrane (13.1, 26.2, 41.0 and 19.7% for no C20orf54 staining, weak staining, medium staining and strong staining, respectively). Defective expression of C20orf54 in tumor cells was significantly associated with poor differentiation. However, other parameters such as depth of invasion and lymph node metastasis had no significant relationship with C20orf54 expression. The average blood concentration of riboflavin was 2.6468 ± 1.3474 ng/ml in ESCC patients lower than control group (4.2960 ± 3.2293 ng/ml, P = 0.015). A positive correlation of plasma riboflavin levels with defective expression of C20orf54 protein was found in ESCC patients (F = 8.626; P = 0.038). Defective expression of C20orf54 is associated with the development of Kazak esophageal squamous cell carcinoma and this may represent a mechanism underlying the decreased plasma riboflavin levels in ESCC.