Two-dimensional electrophoretic analysis of membranous protein from human thyroid tissues and cancer cell lines

Thyroid neoplasm is the most commonly encountered neoplastic disorder in endocrine clinics. Thyroid scan, ultrasonography, and fine needle aspiration cytology (FNAC) are used as diagnostic tools to differentiate a malignant nodule from a benign lesion. There are certain limitations and pitfalls in FNAC, especially in the diagnosing of follicular tumors. The lack of characteristic findings or a specific tumor marker are the most common problems in the preoperative diagnosis of thyroid follicular carcinoma. Although serum thyroglobulin level has been used as a tumor marker for post-operative, well-differentiated thyroid cancer, the assay cannot be used for preoperative diagnosis of thyroid carcinoma. In this study, various thyroid tissues and cancer cell lines including CGTH W-1, CGTH W-3, RO 82 W-1, SW 579 cell lines were used for the investigation of tumor markers. Specific spots were identified in the area near the 60 kDa molecular mass protein and isoelectric point (pI) 5.9 of the CGTH W-1 cell line. These spots could not be found in the papillary or anaplastic thyroid cancer cell lines. Another spot with a molecular weight of about 9.8 kDa with a low pI of 4.8 was present in the CGTH W-1 and RO 82 W-1 cell lines. This spot appeared to be a tumor marker of follicular cancer cells. This spot could not be found in the papillary and anaplastic cancer cell lines and other benign thyroid tissues. Specific proteins that were identified in this study may be useful as tumor markers for follicular thyroid carcinoma.