The Clinicopathological Results Of Thyroid Cancer With Braf(V600e) Mutation In The Young Population Of Fukushima

Background: Thyroid ultrasound screening for children aged 0 to 18 years was performed in Fukushima following the accident at the Fukushima Daiichi Nuclear Power Plant. As a result, many thyroid cancer cases were detected. To explore the carcinogenic mechanisms of these cancers, we analyzed their clinicopathological and genetic features.Methods: We analyzed 138 cases (52 males and 86 females) who had undergone surgery between 2013 and 2016 at Fukushima Medical University Hospital. Postoperative pathological diagnosis revealed 136 (98.6%) cases of papillary thyroid cancer (PTC).Results: The BRAF(V600E) mutation was detected using direct DNA sequencing in 96 (69.6%) of the thyroid cancer cases. In addition, oncogenic rearrangements were detected in 23 cases (16.7%). Regarding chromosomal rearrangements, 8 (5.8%) RET/PTC1, 6 (4.3%) ETV6(ex4)/NTRK3, 2 (1.4%) STRN/ALK, and 1 each of RET/PTC3, AFAPIL2/RET, PPFIBP/RET, KIAA1217/RET, ARFP/RET, SQSTM1/NTRK3 and TPR/ NTRK1 were detected. Tumor size was smaller in the BRAF(V600E) mutation cases (12.8 +/- 6.8 mm) than in wild-type BRAFcases (20.9 +/- 10.5 mm). In the BRAF(V600E) mutation cases, 83 (86.5%) showed lymph node metastasis, whereas 26 (61.9%) of the wild-type BRAF cases showed lymph node metastasis.Conclusions: The BRAF(V600E) mutation was mainly detected in residents of Fukushima, which was different from post-Chernobyl PTC cases with RET/PTC3 rearrangement. PTC with the BRAF(V600E) mutation was smaller but was shown in the high rate of central cervical lymph node metastasis than the wild-type BRAFPTC in the young population of Fukushima.