Analysis of protein profile MAGE A3, P53, MDM2 and KAP-1 in malignancy identification and in the characterization of thyroid follicular lesions

Author(s)

Mariana Bonjiorno Martins

• Document type: Master's Dissertation
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 23-07-2012

Examining board members

André Almeida Schenka; Hans Graf

• Advisor: Laura Sterian Ward

Abstract

The lesions of thyroid follicular constitute about 30% of thyroid lesions and are a major clinical problem since they include benign and malignant conditions. This requires patients who are potential candidates to perform surgery, which appears unnecessary in 70% of indeterminate cytology that the histological examination revealed to be benign. The antigens Cancer Testis have member as MAGE A3, a specific protein involved in regulation of apoptosis and cell cycle progression. The TP53 is a tumor suppressor, its protein p53 has a fundamental role in cell cycle control, DNA repair and activation of apoptosis, and is responsible for transcription of MDM2, which inhibits the functions of p53 transcribers and produces negative feedback. The KAP-1 protein can act as a co-repressor of p53 to bind to MDM2 and MAGE A3 and it has been implicated in diverse cellular processes such as development, differentiation and neoplasic transformation. This paper sets to analyze the expression of MAGE A3, P53, MDM2 and KAP-1 as potential markers for diagnosis and prognosis of Differentiated Thyroid Cancer. We used immunohistochemistry to evaluate protein expression. We investigated 364 patients with thyroid nodules (malignant and benign tissue). The expression of all proteins identified malignancy (p <0.0001) and also can differentiate between some follicular lesions. Protein expression of MAGE A3, P53, MDM2 and KAP-1 were associated with clinical and pathological aggression, but only KAP-1 correlated with tumor recurrence, but not with patient survival. Our data suggest that the expression of MAGE A3, P53, MDM2 is not a good marker of recurrence, but all proteins may help in the differential diagnosis of follicular thyroid lesions and to confirm malignancy and may be useful as part of a panel of markers that help diagnosis of differential thyroid câncer. (AU)