A Study On Relation Between BRAF^V600E Mutation And TERT Promoter Mutation With Clinicopathologic Characteristics Of Papillary Thyroid Carcinoma

Objective The incidence of thyroid carcinoma?TC?is increasing rapidly in the world in recent decades.It is one of the most common malignancies in the endocrine system.According to the histopathological classification of thyroid cancer,TC is divided into four pathological types,of which papillary carcinoma is the most common pathological type.The occurrence and development of papillary thyroid carcinoma?PTC?is regulated by many genes.Among them,BRAF^V600E gene mutation and TERT promoter mutation are important genetic changes of PTC.In this study,we collected fresh frozen tissue and clinical pathology data from patients with PTC.The mutation rates of BRAF^V600E and TERT promoters were determined.Combined with the clinicopathological data of patients,the effects of BRAF^V600E600E and TERT gene mutations and common mutations on pathological features were analyzed.Although PTC has a good differentiation,a low degree of malignancy,and a high postoperative survival rate,there are still some cases of recurrence and metastasis,or even death.Therefore,a correct and comprehensive understanding of the mutation characteristics and interactions of BRAF^V600Eand TERTgenes in PTC can help provide a basis for diagnosis and individualized treatment of PTC patients,so as to lay the foundation for target gene therapy.Method The tumor tissues were collected at the Affiliated Hospital of Jining Medical College,and criteria for inclusion in the study:patient had no radiochemotherapy after diagnosis;and no exposure to radiation;diagnosed as PTC by at least 3 pathologists.The clinical and pathological data of the patient?gender,age,tumor size,lymph node metastasis,presence or absence of extra-thyroidal invasion,and presence or absence of capsular invasion?were collected.Cryosections were made from fresh frozen tissue of 62 patients with PTC,cancer cells were collected by microdissection.DNA of tumor cells was extracted by Chelex-100 method.Primers were designed based on the mutation sites for polymerase chain reaction?PCR?and the quality of PCR products was determined by agarose DNA electrophoresis.The qualified PCR products were sent to Shanghai Bioengineering Company for Bi-directional sequencing.The mutation rates of BRAF^V600E and TERT promoters were analyzed,to determine the effects of these two gene mutations on the clinicopathological features of PTC patients were statistically analyzed.Result Of the 62 PTC patients,58?93.55%?had BRAF^V600E gene mutations.13?20.97%?had TERT mutations at C228T of its promoter.There were 41 BRAF^V600E gene mutations in female PTC patients?93.18%?and 17 in male PTC patients?94.44%?.The BRAF^V600E gene mutation was not associated with gender in PTC patients?P>0.05?.Similarly,the BRAF^V600E600E gene was mutated in 3 patients with extra-thyroidal invasion with a mutation rate of 100.00%.55 cases of BRAF^V600E mutation were detected in 59 patients without extra-thyroidal invasion,and the mutation rate was 93.22%.The difference between the two groups was not statistically significant?P>0.05?.In 25 cases of PTC patients with tumor diameter?1cm,there were 21 cases?84.00%?of BRAF^V600E gene mutations,while all of the 37 PTC patients with tumor diameter>1cm had BRAF^V600E gene mutations.There was a statistically significant difference between the two groups?P<0.05?.The incidence of BRAF^V600E gene mutation was100.00%in 9 patients with lymph node metastasis in the neck,and the mutation was 92.45%in 53 PTC patients without cervical lymph node metastasis.There was no significance statistical difference between the two groups?P>0.05?.The TERT promoter mutation in PTC patients was not associated with gender?P>0.05?.However,the TERT promoter mutation rate was 0.00%in 25 PTC patients with tumor diameter?1cm,which was significantly lower that in patients with tumor the diameter>1cm?35.14%?.The difference was statistically significant?P<0.05?.There was no significant difference?P>0.05?between the TERT promoter mutation group and the TERT wild group in whether they invaded the thyroid capsule,whether there was extragonadal metastasis,or whether lymph node metastasis occurred.In patients with both BRAF^V600E and TERT promoter mutations,the tumor diameter was significantly greater in patients with no mutations?P<0.05?.Conclusion In this study,the BRAF^V600E600E mutation rate was 93.55%and the TERT mutation rate was 20.97%.Both of them are significantly associated with tumor size.