Rearrangement analysis in archival thyroid tissues: punching microdissection and artificial RET/PTC 1-12 transcripts

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• The clinical significance of RET hybrid oncogene variants (RET/PTC) in thyroid carcinoma remains debated.
• Large patient cohorts and pathological archives are crucial for studying RET/PTC prognostic value.

Purpose of the Study:

• To establish and validate efficient techniques for analyzing RET/PTC rearrangements in archival thyroid tumor tissues.
• To investigate the prevalence of known RET/PTC variants in oxyphilic thyroid tumors.

Main Methods:

• Manual punching macrodissection of formalin-fixed, paraffin-embedded thyroid neoplasms.
• RNA extraction followed by reverse transcriptase polymerase chain reaction (RT-PCR) for RET rearrangement screening.
• Hybrid-specific expression analysis using artificially constructed RET/PTC sequences as controls.

Main Results:

• Manual dissection effectively reduced wild-type RET contamination.
• Ten of fifteen RET rearrangements were identified in 54 oxyphilic thyroid tumors (8x RET/PTC 1, 2x RET/PTC 3, 5x RET/PTC x).
• The study confirmed the absence of rare chimeric transcripts, suggesting RET/PTC x may be novel or unamplifiable due to RNA degradation.

Conclusions:

• The described microdissection and RT-PCR methods are fast, simple, and adaptable for molecular biology labs.
• These techniques facilitate large-scale screening of archival thyroid tumors for known and novel RET rearrangements.
• This approach supports further investigation into the prognostic significance of RET/PTC chimeras in thyroid cancer.