Immunohistochemical evaluation of midkine and nuclear factor-kappa B as diagnostic biomarkers for papillary thyroid cancer and synchronous metastasis

AimsMidkine (MK) is a multifunctional cytokine identified to be a promising cancer biomarker. Nuclear factor-kappa B (NF-κB) is an important transcription factor that plays a pivotal role in tumorigenesis. We aimed to investigate values of MK and NF-κB as markers for diagnosis and synchronous metastasis prediction in papillary thyroid cancer (PTC).Main methods76 cases of PTC and 70 cases of multi-nodular goiter (MNG) were retrieved. The PTC group was further divided into subgroup 1 (16 cases with synchronous metastases) and subgroup 2 (60 cases without metastases). A retrospective review of demographic and clinical information was performed. Immunohistochemistry of MK, NF-κB p65 and Ki-67 was performed on paraffin-embedded specimens and results were quantified. Diagnostic values of the parameters were conducted by receiver operating characteristic (ROC) curves. Protein levels of MK and NF-κB p65 were then confirmed by Western blot.Key findingsImmunoreactivities of MK, NF-κB p65 and Ki-67 were significantly higher in the PTC group than in the MNG group with good differential diagnostic capabilities. Moreover, immunoreactivities of all three parameters were significantly higher in subgroup 1 than in subgroup 2 with good synchronous metastasis predictive efficacies. Western blot showed that MK and NF-κB p65 protein levels in lesions from subgroup 1 were significantly higher than those from subgroup 2, both of which were significantly higher than in MNG lesions.SignificanceWe discovered that MK and NF-κB immunohistochemistries can potentially be used for differential diagnosis between PTC and MNG, and for prediction of synchronous metastases.