Prognostic Role of β-catenin/PTEN Expressions and Braf/Kras Mutations in Papillary Thyroid Carcinoma: Correlation with Response to Radioactive Iodine Therapy

Background: Papillary thyroid carcinoma (PTC) is the most common endocrine 
cancer; nevertheless, despite a favorable prognosis, some PTCs demonstrate 
aggressive behavior and are refractory to radioactive iodine therapy (RAIT). 
The study aims to evaluate the association between PTEN/β-catenin expression 
as well as BRAF/KRAS mutations on the pathological features and 
responsiveness to RAIT.
Methods: A retrospective study included 52 cases of PTC. β-catenin and PTEN 
expressions were evaluated by immunohistochemistry. BRAFV600 and KRAS 
mutations were evaluated using PCR technique. All patients underwent 
thyroidectomy followed by RAIT, and at least 12 months of follow-up 
following initial therapy. 
Results: The study included 52 patients (38 females and 14 males, mean age:
42.07±14.17 years). Lost β-catenin membranous expression was significantly 
associated with nodal metastasis (P=0.011), lymphovascular invasion (P=0.041), 
and higher cumulative doses of RAI (P=0.0.034). Positive β-catenin cytoplasmic 
expression was significantly linked to persistent/recurrent structural disease 
(P=0.007). Negative PTEN cytoplasmic expression was significantly associated 
with advanced TNM staging (P=0.022), thyroid capsular infiltration, and 
extrathyroidal extension (P=0.005 and 0.008, respectively). There was no 
significant relationship found between PTCs harboring BRAFV600E mutation and 
pathological characteristics or responsiveness to RAI (P=0.521). 
Conclusions: Our results demonstrate that PTCs lacking membranous and 
expressing cytoplasmic β-catenin are significantly linked to more aggressive 
pathology, greater RAI dosages, and disease recurrence/persistence. Negative 
PTEN expression is substantially associated with advanced TNM staging and 
pathological characteristics. Furthermore, our data suggest that a positive BRAF 
mutation has no significant impact on RAIT efficacy in PTC patients without 
known distant metastases.