Abstract: Objective: To investigate the major mutations in patients with papillary thyroid carcinoma at Wannan region of Anhui.Methods: Thirty-three paraffin-embedded samples were collected.After extraction of DNA,the glutamate replaced valine(V600E) of v-raf murine sarcoma viral oncogene homolog B1(BRAF) gene,and the mutations in 12 and 13 codon of K-ras gene were detected using polymerase chain reaction and gene sequencing.Serum total triiodothyronine,free triiodothyronine,total tetraiodothyronine,free tetraiodothyronine and thyroid stimulating hormone of all the cases were measured by luminescentimmunoassay before operation.Results: V600E mutation of BRAF was detected in 13 of the 33 cases(39.4%);Meanwhile,no mutation in 12 and 13 codon of K-ras gene was detected.There was no significant association between V600E mutations of BRAF and the gender,age or diameter of the tumor.The levels of serum triiodothyronine,free triiodothyronine and thyroid stimulating hormone in patients with V600E mutation of BRAF were significantly lower than those in patients without V600E mutation of BRAF(P<0.05 to P<0.01).The levels of serum free tetraiodothyronine in patients with V600E mutation of BRAF were significantly higher than those in patients without V600E mutation of BRAF(P<0.01);the level of serum total tetraiodothyronine had no significant difference between the two groups(P>0.05).Conclusions: V600E mutation of BRAF gene is the major mutation in papillary thyroid carcinoma patients at Wannan region of Anhui