Serum Sialyl Fibronectin Is an Indicator of Good Prognosis in Thyroid Cancer

Background/Aim: Sialyl-fibronectin (S-FN), a type of glycoprotein like Sialyl Lewisa and MAC1 thyroid cancer biomarkers, has been found to be expressed in thyroid cancer. In this study, we examined the usefulness of serum S-FN as a biomarker, as well as prognostic factor in various tumors including thyroid cancer. Patients and Methods: Using the MoAb JT-95, an ELISA kit was created and S-FN levels in sera (blood S-FN) of a total of 182 cases were investigated. Analysis included 63 cases of thyroid cancer, 33 cases of thyroid benign tumors, 7 cases of parathyroid benign tumors, and 79 cases of breast cancer. Results: The incidence of blood S-FN-positive cases was 24 (38.0%) in 63 examined patients with thyroid cancer. Out of 40 examined benign neck tumor cases, 16/40 (40%) were S-FN-positive. Out of 79 examined breast cancer cases, 20/79 (25.3%) were S-FN-positive, with significant differences between thyroid and breast cancer cases (p=0.007). Regarding the association of blood S-FN expression and prognosis in thyroid cancer, there was a significant difference between 39 blood S-FN-negative cases and 15 recurrent or metastatic cases in terms of progression and pathological factors: tumor size, lymph node metastasis, extra-membrane infiltration, and clinical stage. All 63 assessed thyroid cancer cases also had a significant difference in these factors. There were no significant differences between these factors in the 24 blood S-FN-positive thyroid cancer cases. In cases of recurrent metastasis, intravascular cells were observed in all recurrent metastasis patients of both groups. Regarding staining of intravascular infiltrating cells, recurrent metastasis appeared at a higher rate in cases with S-FN-negative infiltrating cells. Conclusion: S-FN presence in blood can be used as an indicator of good prognosis in thyroid cancer patients.