Background:

About 25% of patients suffering from medullary thyroid carcinoma (MTC) have been associated to germinal pathogenic variants of RET proto-oncogene. Multiple endocrine neoplasia type 2 (MEN2) and familial medullary thyroid carcinoma (FMTC) are phenotypes related germinal RET pathogenic alterations. Despite the vast research on genomics about MTC in European descendants, little is known in Latin America.

Objective:

The aim of this study was to assess germinal pathogenic genetic variants of RET proto-oncogene in a Peruvian cohort of patients with MTC.

Materials and Methods:

We conducted a descriptive, observational, and retrospective study of patients with diagnosis of MTC who attended at least one genetic consultation at a national Peruvian oncologic healthcare institute, whose germinal genetic results of RET gene were available on clinical records. Genetic analysis was carried out using the Sanger sequencing methodology evaluating RET gene exons: 10, 11, 13, 14, 15, and 16. We collected personal and familial information and morphological tumor-relevant information.

Results:

We found 28.6% (6/21) of probands diagnosed with MTC carrying a germinal pathogenic variant of RET gene. Half or these germline alterations were de novo. We identified five germinal pathogenic variants: p.Cys620Ser, p.Cys630Ser, p.Cys634Gly, p.Cys634Arg, and p.Leu790Phe.

Conclusion:

This is the first report of germinal pathogenic variants of RET proto-oncogene found in Peruvian patients with MTC, with unique findings highlighting the importance of genomic analysis for precise diagnosis for personalized clinical management.