[Analysis of BRAF and NRAS mutations in thyroid tumors in patients from Argentina]

INTRODUCTION

Molecular alterations in follicular cells in the BRAF or NRAS genes have been reported to be associated with the process of carcinogenesis. Our aim was to determine the mutational frequency of BRAF and NRAS in fine-needle aspiration (FNA) specimens in our population.

METHODS

The mutational status of BRAF (codon 600) and NRAS (codon 61) was analysed by qPCR in 193 FNA specimens from suspicious nodules and compared with pathological data of 115 patients.

RESULTS

BRAF mutation was identified in 40 samples (74.1%) of FNAs classified as Bethesda VI (n = 54). In samples histologically diagnosed as classic papillary thyroid carcinoma (cPTC, n = 47), mutation was observed in 70% of cases, while in other subtypes the prevalence was lower (p = 0.013). In FNA specimens of follicular lesions (n = 36), positivity for NRAS was found in 50% of the follicular carcinomas (FTCs), but only in 6.7% of adenomas. Finally, there was a significant correlation between BRAF and PTC with lymph-node metastasis (p = 0.014) and increased relative risk of recurrence based on the Argentine Intersociety Consensus (RR = 6.77, p = 0.022). No significant differences were found between BRAF mutation and other features of aggressiveness in PTC.

CONCLUSION

BRAF and NRAS mutations are observed in a significant number of PTCs and FTCs, in our population. There is a significant correlation between BRAF mutation and lymph-node metastasis.

ODP465 BRAF V600 and NRAS Q61 mutations in thyroid fine-needle aspiration (FNA) with indeterminate cytology in Argentina

 

It is known that thyroid cancer initiation and progression occurs because of gradual accumulation of genetic and epigenetic alterations at cell level. Many mutations associated with this disease have been reported to be present in genes encoding proteins in the mitogen-activated protein kinase (MAPK) signaling pathway, specifically BRAF and RAS genes, as well as in the PI3K/Akt signaling pathway, among others. In particular, molecular alterations in follicular cells in the BRAF or NRAS genes have been reported to be associated with the process of carcinogenesis. Previously we found BRAF and NRAS mutations are observed in a significant number of papillary and follicular thyroid carcinomas in our population, respectively. In this study, we tested the diagnostic performance of BRAF and NRAS mutation in thyroid carcinoma in fine-needle aspiration (FNA) specimens with indeterminate cytology. In total, residual material from 73 FNA samples was used (n= 16, Bethesda III; n=48, Bethesda IV and n=9 Bethesda V). BRAF codon 600 mutation and NRAS codon 61 mutations were investigated using qPCR and melting curve analysis was carried out. Diagnosis of malignancy was confirmed by histology on paired surgical specimen in 54 cases.

Results

In the cytologically indeterminate categories, 9.6% of specimens were BRAF V600 mutated: 1 of 16 were subcategorized as atypia of undetermined significance or follicular lesion of undetermined significance (6.3%); 2 of 48 as follicular neoplasm or suspicious for follicular neoplasm (4.1%); and 4 of 9 as suspicious for malignancy (44.4%). NRAS Q61 mutation was found in 4 patients (2 with Bethesda IV and 2 with cytology V). The BRAF V600 mutations were associated with carcinoma in 100% of cases (n = 7), whereas only 75% (n = 3) of the nodules with NRAS were associated with carcinoma. BRAF V600 and NRAS Q61 mutations had high specificity in predicting malignant carcinoma (96.8%); the sensitivity was 43.5% with a positive predictive value of 90.9% and a negative predictive value of 69.8%. In specific categories of indeterminate cytology, the pre-test risk of malignancy was 38%, 33% and 88% while the post molecular test risk of malignancy was 100%, 75% and 100% respectively.

Conclusions

BRAF V600 and NRAS Q61 molecular test in residual FNA samples improve diagnostic accuracy of the cytology analysis in our population and may help to better select patients for avoid inadequate or unnecessary surgeries.

Presentation: No date and time listed

Local ethanol injection for the treatment of deltoid parathyroid cell hyperplasia

Secondary hyperparathyroidism (SHPT) is a serious complication in dialysis patients and is routinely managed with medical therapy. Refractory disease is usually treated either surgically or by local ethanol injection into the parathyroid glands. Total parathyroidectomy with deltoid implant can be successful; however, recurrent, resistant disease is not uncommon. Local ethanol injection was applied to the deltoid autoimplant of a patient with recurrent, resistant SHPT, which had not been resolved with surgical treatment. Serum intact parathyroid hormone (iPTH) levels subsequently decreased from 1,400 to 219 pg/dl and remained stable for the next 6 months. To our knowledge, this procedure has not been previously described in the literature. Local injection of ethanol may represent an interesting alternative to surgery for the treatment of deltoid parathyroid cell hyperplasia in patients in which surgical treatment is not an option.

Treatment of uremic hyperparathyroidism with percutaneous ethanol injection

The percutaneous ethanol injection (PEI) with ultrasound guidance has been suggested for the treatment of patients with hyperparathyroidism who are on dialysis, with the aim of selectively treating the parathyroid glands with nodular hyperplasia. We present our experience in 25 patients with chronic renal failure followed during 13.4 +/- 10.6 months. A decrease in the levels of parathormone (PTH) (1,236.32 +/- 129.8 vs. 721.66 +/- 142.24 pg/ml), phosphatemia (6.16 +/- 0.35 vs. 4.93 +/- 0.36 mg/dl) and calcium-phosphorous product (60.82 +/- 3.81 vs. 46.47 +/- 3.46 mg2/dl2) was verified. In 56% of patients, PTH levels decreased (>50% of the baseline value) and 36% had final values <300 pg/ml. Patients in whom ultrasound showed a single gland responded better than those with more than one gland (83.3 vs. 30.8% of responders in each group). The procedures performed had a 4.9% complication rate: hematoma, symptomatic hypocalcemia, temporary paresis of the vocal cords. In summary, treatment with PEI is useful for the management of patients with hyperparathyroidism who are on dialysis, and the results achieved are better in patients who have a single gland identified by ultrasonography.