European Journal of Molecular & Clinical Medicine

Abstract

Background: The Prevalence of thyroid nodules is rising nowadays, luckily most of
them are benign. The risk of malignancy 5-15%, which necessitates the ultimate need to
accurately distinguish benign from malignant nodule to avoid unnecessary
thyroidectomy with risk of recurrent laryngeal nerve injury, postoperative
hypothyroidism and lifetime thyroid replacement therapy, and other complications
related to surgery and anaesthesia. Recent evidence suggests that circulating miRNA
might have probable advantage as diagnostic or prognostic markers for numerous
cancers. Given their reproducible and constant presence in sera, miRNA profiles have
emerged as a non-invasive method to categorise a wide variety of human cancers. This
study aimed to evaluate a possible relationship between the expression level of
circulating miRNA-222 and the histological outcome of euthyroid patients undergoing
thyroidectomy for thyroid nodules with indeterminate FNAC. This study included 45
euthyroid patients with inderteminate thyroid nodules diagnosed with ultrasound and
FNAC which planed for thyroidectomy. Quantitative assay of serum micro RNA-222
expression by quantitative Real-Time polymerase chain reaction (qRT-PCR) performed
preoperatively, and results compared with postoperative histopathology.
Results: The incidence of thyroid nodules was predominant in female gender in benign
group and malignant group. Risk of malignancy increases as TI-RADS and Bethesda
scores increases. Also, larger nodule in size has a more risk of malignancy (p= 0.027).
Expression level of circulating miRNA-222 in serum can’t differentiate between benign
and malignant patients where there was no significant difference between them
statistically (p=0.905). Circulating miRNA-222 was a poor predicator for malignant
nodules with sensitivity of 50%, specificity of 32.43%, with high negative predictive
value (NPV=75%).
Conclusion: Although circulating miRNA-222 has been identified as novel minimally
invasive biomarker for preoperative prediction of malignant nodules, but in our study,
it did not show a value as a tool for discrimination of malignant nodules. Ultrasound
remained important procedure in preoperative prediction and management of thyroid
nodules especially when correlating to nodule size which had positive correlation with
malignancy in our study.