Role of BRAF, RAS and RET/PTC mutations in predicting aggressiveness of well-differentiated thyroid cancers

  • Background: In India the number of incident cases of thyroid cancers is 1,157,294 and the age-standardized incidence rate per 1 lakh population is 89.4 according to Globocan 2018 data. Presence of BRAF, RAS and RET/PTC mutations categorizes the patient into intermediate-risk group of ATA initial risk stratification1. Although there are several studies on prevalence of gene mutations from the west, there is no such data from India. Methods: This study was done on archival blocks of patients with well-differentiated thyroid cancers who underwent complete panel of treatment in our institution. Paraffin blocks of thyroid cancer cases which showed aggressive features clinically and on histology were retrieved. DNA was extracted from formalin-fixed paraffin embedded sections and was subjected to PCR to amplify the gene of interest followed by direct sequencing to identify the mutations. Results: In our study, BRAF mutation is the most common genetic alteration occurring in about 76% of papillary thyroid cancers (PCTs) and was identified in 82% of cases which recurred following treatment. There was a significant correlation between BRAF mutation and lymph node metastasis in PCTs. Discussion & Conclusion: There is a high prevalence of BRAF, RAS and RET/PTC mutations in well-differentiated thyroid cancers among Indian population. These mutations are prognostic markers in assessing the aggressiveness of thyroid cancers. Presence of BRAF mutations play a significant role in upstaging the patients to intermediate-risk category of ATA initial risk stratification who then will require adjuvant therapy and more aggressive follow-up when compared to low-risk group.

 

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