Comprehensive analysis of 112 melanocytic skin lesions demonstrates microsatellite instability in melanomas and dysplastic nevi, but not in benign nevi

J Cutan Pathol. 2001 Aug;28(7):343-50. doi: 10.1034/j.1600-0560.2001.280702.x.


Introduction: the length of DNA repetitive sequences (microsatellite instability (MSI)) represent distinct tumorigenic pathways associated with several familial and sporadic tumors.

Material and methods: To investigate the prevalence and frequency of MSI in melanocytic lesions, the polymerase chain reaction (PCR)-based microsatellite assay was used to examine formalin-fixed, paraffin-embedded tissues of 30 benign melanocytic nevi, 60 melanocytic dysplastic nevi (MDN), and 22 primary vertical growth phase cutaneous malignant melanomas (CMM). Twenty-four microsatellite markers at the 1p, 2p, 3p, 4q and 9p chromosomal regions were used.

Results: MSI was found at 1p and 9p in MDN and CMM but not in benign melanocytic nevi. The overall prevalence of MSI was 17/60 (28%) in MDN and 7/22 (31%) in CMM. The frequency of MSI ranged from 2/24 (9%) to 4/24 (17%) and was most commonly found at D9S162. There was a statistically significant correlation between degree of atypia and frequency of MSI (p<0.001) in MDN. There were two MSI banding patterns: band shifts and additional bands.

Conclusions: The data presented revealed the presence of low-frequency MSI (MSI-L) at the 1p and 9p regions in both MDN and CMM. Whether the MSI-L pattern reflects a defect in mismatch repair genes is still to be determined.

MeSH terms

  • Chromosome Mapping
  • Dysplastic Nevus Syndrome / genetics*
  • Gene Frequency
  • Humans
  • Melanocytes / pathology*
  • Melanoma / genetics*
  • Microsatellite Repeats*
  • Nevus / genetics*
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / pathology*