Analysis of microsatellite instability using Promega panel in dermatofibrosarcoma protuberans

Area of Science:

• Oncology
• Dermatology
• Cancer Genomics

Background:

• Dermatofibrosarcoma protuberans (DFSP) is a rare skin neoplasm originating from fibroblasts.
• Microsatellite instability (MSI) is infrequent in skin cancers (<5%), with limited data on mismatch repair (MMR) status in DFSP.
• Previous studies reported varying MSI frequencies in DFSP, but without using the standard Promega panel.

Purpose of the Study:

• To evaluate the mismatch repair (MMR) status and microsatellite instability (MSI) in a cohort of 36 Dermatofibrosarcoma protuberans (DFSP) patients.
• To clarify the role of MSI in the pathogenesis of DFSP.
• To assess the potential therapeutic implications of MMR status, particularly concerning pembrolizumab treatment.

Main Methods:

• Analysis of microsatellite stability (MSS) and microsatellite instability (MSI) in 36 DFSP patient samples.
• Utilized the Promega MSI analysis system for standardized assessment.
• Compared findings with previous reports on MSI in DFSP.

Main Results:

• All 36 analyzed cases of Dermatofibrosarcoma protuberans (DFSP) were found to be microsatellite stable (MSS).
• The study demonstrated a complete absence of microsatellite instability (MSI) in the DFSP cohort.
• This contrasts with some prior reports that utilized non-standardized methods.

Conclusions:

• Dermatofibrosarcoma protuberans (DFSP) does not exhibit microsatellite instability (MSI).
• Mismatch repair (MMR) status is unlikely to be a predictive biomarker for pembrolizumab therapy in DFSP.
• The pathogenesis of DFSP does not appear to involve microsatellite instability (MSI).