Relationship of PPARG overexpression with prognostic parameters in papillary thyroid carcinoma

Abstract

Objectives. PAX8/PPARG chromosomal rearrangement is frequently seen in thyroid cancer, and PPARG overexpression has been shown in the follicular variant of papillary thyroid carcinoma, but not in papillary thyroid carcinoma other than the follicular variant. The main aim of this study was to investigate the frequency of PPARG overexpression among papillary thyroid carcinoma and if there were any variants of papillary thyroid carcinoma with PPARG overexpression other than the follicular variant. Methods. Immunohistochemical analysis of PPARG overexpression was performed using a PPARG monoclonal antibody in a series of 111 paraffin-embedded blocks of thyroid tumours. Of the patients in our study, 100 were diagnosed with papillary thyroid carcinoma, 9 with follicular adenoma and 2 with follicular carcinoma. Results. PPARG staining was detected in 19 of the 111 cases. Sixteen patients with PPARG overexpression had papillary thyroid carcinoma and 3 had follicular adenoma. Conclusion. PPARG overexpression was detected mainly in follicular-variant papillary thyroid carcinoma. Vascular invasion, lymphatic invasion, thyroid capsule invasion and lymph node positivity were lower in patients with PPARG overexpression. KEY WORDS: papillary thyroid carcinoma, PPARG overexpression, prognostic parameters, PAX8/PPARG fusion protein (PPFP), pioglitazone RIASSUNTO Obiettivi. Il riarrangiamento cromosomico PAX8/PPARG è frequentemente osservato nel cancro della tiroide, la sovraespressione della proteina PPARG è stata già dimostrata nella variante follicolare del carcinoma papillare della tiroide, ma non nelle varianti del carcinoma papillare della tiroide, diverse da quella follicolare. L'obiettivo principale di questo studio è stato quello di indagare la sovraespressione di PPARG nel carcinoma papillare della tiroide e se ci sia qualche variante del carcinoma papillare della tiroide, diversa da quella follicolare, con sovraespressione di PPARG. Metodi. È stata eseguita una analisi immunoistochimica della sovraespressione di PPARG, utilizzando un anticorpo monoclonale PPARG in una serie di 111 campioni di tumori tiroidei inclusi in paraffina. In 100 casi, è stato diagnosticato un carcinoma papillare della tiroide, in 9, adenoma follicolare e 2, carcinoma follicolare. Risultati. La proteina PPARG è stata rilevata in 19 dei 111 casi. Sedici di quei pazienti con sovraespressione di PPARG avevano carcinoma papillare della tiroide e 3 pazienti avevano adenoma follicolare. Conclusione. La sovraespressione di PPARG è stata rilevata principalmente nella variante follicolare del carcinoma papillare della tiroide. L'invasione vascolare, l'invasione linfatica, l'invasione della capsula tiroidea e la positività dei linfonodi sono risultate inferiori nei pazienti con sovraespressione di PPARG.

Autophagy-Related MicroRNA: Tumor miR-125b and Thyroid Cancers

“…Thyroid cancers are prevalent in women, indicating the sex hormone disorders as an essential risk factor [ 84 ]. The peroxisome proliferator receptor gamma (PPARγ) alteration associated with steroids transcriptional factors was detected only in follicular thyroid cancer and follicular adenoma [ 85 ].…”

“…The association of hsa-mir-125b with STAT3, PRDM1, TP53, EZH2, NFkB1, AKT1, ERS1 and PPARG was revealed. The complex of factors represented the processes activated in PTC development [ 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 ]. They recover the mechanism of immune response, microenvironment modification, hormone receptors signal transduction, oxidative stress and etc.…”

Molecular genetic markers of highly differentiated thyroid cancer (literature review and personal observations)

“…Genetic mutations of PAX8/PPARγ are more common in young patients with small tumours with vascular invasion [54,55]. A PAX8/PPARγ mutation is not a diagnostic sign of malignancy, but should prompt a thorough search for vascular or capsular invasion.…”

Indeterminate Thyroid Nodules: From Cytology to Molecular Testing

“…In thyroid cancer, the PPARG gene is rearranged with PAX8 , a gene encoding for a transcription factor required for thyroid differentiation. PAX8/PPARG is a chimeric oncogenic protein that promotes cell growth and reduces the rate of apoptosis [ 25 , 26 ].…”