[Hereditary medullary thyroid carcinoma--genotype-phenotype characterization].

Area of Science:

• Oncology
• Genetics
• Endocrinology

Background:

• Hereditary medullary thyroid carcinoma (MTC) arises from germline mutations in the RET proto-oncogene.
• Specific RET mutations correlate with distinct clinical syndromes like MEN 2A and MEN 2B.
• Variability in MTC development and aggressiveness across different cancer syndromes is suggested.

Purpose of the Study:

• To compare the clinical phenotype of patients with RET mutations in exons 13-15 versus exon 11 (codon 634).
• To evaluate potential therapeutic implications based on genotype-phenotype correlations.
• To inform clinical management strategies for hereditary MTC.

Main Methods:

• Phenotypic comparison of 47 patients with exon 13-15 mutations against 66 patients with exon 11 (codon 634) mutations.
• Subdivision of patients into index and screening cohorts for detailed analysis.
• Analysis of age at diagnosis, tumor stage, cure rates, and mortality.

Main Results:

• Index patients with exon 13-15 mutations (codons 790, 791, 804, 891) had a significantly later age at diagnosis (50 vs. 31 years) compared to codon 634 mutation carriers.
• Favorable tumor stage at operation, better cure rates (56% vs. 38%), and lower death rates were observed in the exon 13-15 group.
• No significant differences in age, tumor stage, cure, or death rates were found between the groups in screening patients.

Conclusions:

• RET mutations in codons 790, 791, 804, and 891 are associated with a later onset and more indolent course of MTC compared to codon 634 mutations.
• These genotype-phenotype differences necessitate consideration when determining the optimal timing and extent of prophylactic surgery.
• Personalized management strategies based on specific RET mutation profiles are crucial for hereditary MTC.