CLIC1 plasma concentration is associated with lymph node metastases in oral squamous cell carcinoma

Background. Previous studies have shown that the chloride intracellular channel 1 (CLIC1) protein is overexpressed in oral squamous cell carcinoma (OSCC) and nasopharyngeal carcinoma. Patients with these diseases had significantly higher CLIC1 plasma levels than healthy controls. Objectives. To determine the plasma concentration of CLIC1 in patients with OSCC and laryngeal squamous cell carcinoma (LSCC). Materials and methods. We collected blood samples from patients diagnosed with OSCC (n = 13) and LSCC (n = 7), as well as from healthy controls (n = 8). The blood samples were centrifuged to obtain plasma and stored at -80 degrees C. The CLIC1 plasma concentration was determined using enzyme-linked immunosorbent assay (ELISA). Results. The mean CLIC1 plasma concentration was higher in the OSCC group than in the LSCC and control groups. Patients with OSCC and nodal metastases had significantly higher CLIC1 plasma concentration levels than nonmetastatic patients (p < 0.0001; Tukey's multiple comparisons test) and controls (p = 0.0004). The CLIC1 concentration correlated significantly with the presence of nodal spread (p = 0.0003; Spearman's r = 0.8613) and overall TNM staging (p = 0.0167; Spearman's r = 0.6620). No differences in CLIC1 plasma levels were observed between the LSCC and control groups. The CLIC1 plasma concentration was not associated with age, sex, tumor stage, or tumor grade. Conclusions. There were no differences in CLIC1 plasma concentration between healthy controls and patients with LSCC. However, our findings suggest that the presence of this protein in plasma may be associated with lymphatic metastasis in patients with OSCC. More research is needed to confirm this possible association.