Enhance C-Myc and cyclinD1 experssion is associated with the recurrence of papillary thyroid carcinoma

Background: A direct role of C-Myc and cyclinD1 genes in the proliferation of human thyroid tumor cells has been identified. In thyroid cancer, a relation had been found withcyclin D1 expression and tumor differentiation, aggressive biological behavior and metastatic .Additional C- Myc also plays a critical role in malignant transformation. Wehave shown that βeta catenin gene expression was positively correlated with recurrence, distant metastasis and TNM stage in papillary thyroid cancer. Cyclin D1, C-Myc aretargets for beta catenin. Objectives: This study aimed to determine if there is an association between C-Myc and cyclinD1 genes expression and the staging, recurrence, metastasis, and disease free survival of papillary thyroid cancer. Materials/Patients and Methods: A retrospective cohort study was conducted using data from available information in the medical records and paraffin blocks of 77 patients referred to the endocrine clinic over a 10-year period. Real-time polymerase chain reaction (PCR) was used to evaluate cyclin D1 and C- Myc gene expression. Disease-free survival was assessed using Kaplan- Meier method.Results: The ten-year survival rate in these patients was 98.25% and disease-free survival was 48.1%. In patients with recurrence, cyclinD1 expression was higher (5.5 fold increasep =0.004) and C- Myc expression was higher too (19.5 fold increase p ≤0.0001). Patients with distant metastasis had higher cyclinD1 and C- Myc gene expression than patientswithout metastasis. There are statistically significant 24.2 fold increase incyclinD1 (p≤0.05) but no increase in C- Myc gene expression (p=0.1). Beta catenin gene expressionhas correlation with C- Myc and cyclinD1 gene expression(r=0.5, P<0.0001) Conclusion: We concluded that in addition to the beta catenin, Cyclin D1 and C-Myc geneexpression are also positively correlated with recurrence, distance metastasis and TNM stage. So it seems that the probable pathway of disease recurrence and aggressiveness inthyroid papillary cancer is the wnt signaling pathway via Cyclin D1 and C-Myc gene.

Keywords:

Cyclin D1 and C-Myc , Papillary Thyroid Cancer , recurrence , survival