Interplay of BRAF and TERT promoter mutations and Ki67 proliferation index in papillary thyroid carcinoma in Central Asians

BACKGROUND: Papillary thyroid carcinoma (PTC) is the most prevalent subtype of thyroid carcinoma, constituting 80-85% of all cases. The clinical challenges posed by PTC are further compounded by its steadily increasing global incidence. Primarily associated with mutations in BRAF V600E and the TERT promoter (TERTp), the aggressive clinicopathological features and poor prognosis of PTC are exacerbated when these mutations co-occur. The Ki67 labeling index (LI), which reflects the proliferation rate of tumor cells, plays a pivotal role in assessing cancer aggressiveness. However, research on mutations in PTC cases in Kazakhstan is limited. METHODS: This retrospective study included 240 patients with PTC. DNA extraction and mutation screening, droplet digital PCR (ddPCR) analysis for BRAF/TERTp mutations and Ki67 immunohistochemistry were performed. Two-sided Fisher's exact test, the Mann-Whitney U test, Kruskal-Wallis test, analysis of variance for nonparametric data were used. RESULTS: In Kazakh PTC cases, BRAF V600E was common (68.3%) and aligned with the patterns observed in the Asian population. TERTp mutations co-occurring with BRAF V600E (4.7%) were associated with advanced age, larger tumor size, lymph node metastasis, higher cancer stage, and higher Ki67 LI (10%). CONCLUSION: This study sheds light on the prevalence of BRAF V600E and TERTp mutations in Kazakhs with PTC. The integration of Ki67 LI assessment and mutation analysis may be instrumental in predicting the aggressiveness of PTC and guiding treatment decisions in this population. CLINICAL TRIAL NUMBER: Not applicable.