Association of BRAF gene and TSHR with cervical lymph node metastasis of papillary thyroid microcarcinoma

Differences in BRAF gene mutation frequency and thyroid-stimulating hormone receptor (TSHR) protein expression in thyroid tissues were detected to investigate their association with local tissue invasion and cervical lymph node metastasis potential of papillary thyroid microcarcinoma (PTMC). The BRAF gene mutation frequency and TSHR expression in PTMC patients were detected via qPCR and immunohistochemical method, and the association between them was discussed combined with the clinical and pathological parameters. Kruskal-Wallis test was used for the univariate correlation analyses and comparison of mutation rate and expression rate, and Chi-square test was used for the association of central lymph node metastasis with BRAF gene and TSHR. The BRAF^V600E mutation only existed in patients with thyroid cancer. Τhe larger the number of metastatic central lymph nodes was, the higher the proportion of BRAF^V600E mutation would be. Τhe BRAF^V600E mutation was related to the primary lesion size, capsular infiltration and lymph node metastasis of PTMC (P<0.05). The expression of TSHR in PTMC tissues was < those in thyroid benign lesions and para-carcinoma normal tissues, which was positively associated with the central lymph node metastasis (P<0.05). Τhe low expression of TSHR was related to the primary lesion size, capsular infiltration and metastatic lymph nodes of PTMC (P<0.05). The BRAF^V600E and TSHR may be involved in the occurrence and lymphatic metastasis of PTMC. The BRAF^V600E mutation has no association with the TSHR protein expression (P=0.256), but the coincidence coefficient indicates that their diagnostic significance in PTMC is not similar, so BRAF^V600E mutation and TSHR protein expression can be used jointly in the prediction of invasion and lymph node metastasis of PTMC, which may be more meaningful for clinical guidance.