Correlation Between the Clinicopathological Features of Papillary Thyroid Carcinoma Complicated with Hashimoto's Thyroiditis, BRAF V600E Gene Mutation, and RET Gene Rearrangement.

OBJECTIVE: To analyse the expression of BRAF V600E protein and RET gene rearrangement in papillary thyroid carcinoma (PTC) combined with Hashimoto's thyroiditis (HT) and to explore its clinical and pathological significance.

STUDY DESIGN: Observational study. Place and Duration of the Study: Department of Pathology, East China Normal University (Wuhu No. 2 People's Hospital), Wuhu, China, from January 2019 to July 2022.

METHODOLOGY: The study population of 150 patients who underwent central lymph node dissection. They were divided into two groups: the PTC group (76/150, 50.7%) and the PTC with HC group (74/150, 49.3%). The expression of BRAF V600E protein was detected using immunohistochemistry, and the RET gene rearrangement status was detected using fluorescence in situ hybridisation. The detection results and clinical pathological characteristics were statistically analysed.

RESULTS: Compared with the PTC group, the prevalence rate of female PTC in HT group was significantly higher than that of the male group, the rate of lymph node metastasis was lower, and the proportion of tumour diameter ≤ 1cm was higher (p < 0.05). However, no significant difference in patient age and multifocality was found between the two groups (p > 0.05). The BRAF V600E positive rate in the PTC combined with HT group (48.6%) was lower than in the PTC group (73.7%), and the RET gene rearrangement positive rate was higher than in the PTC group (p < 0.05). The expression of BRAF V600E protein in PTC combined with HT is correlated with multifocality (p < 0.05), and there is a correlation between RET gene rearrangement and the gender of the patient in the PTC group (p < 0.05).

CONCLUSION: There is a lower rate of BRAF V600E protein positivity in PTC combined with HT patients, as well as a higher rate of RET gene rearrangements positive in PTC combined with HT patients. There is a correlation between multifocality and BRAF V600E protein expression.

KEY WORDS: Papillary thyroid carcinoma, Hashimoto's thyroiditis, BRAF V600E protein, RET gene rearrangement.