Comparative study of the expression of DNA mismatch repair genes, the adenomatous polyposis coli gene and growth arrest DNA damage genes in melanoma recurrences and metastases

The main goal of this study was to examine the expression of DNA mismatch r epair genes (MLH1, MSH2, PMS1 and PMS2), the adenomatous polyposis coli (AP C) gene and growth arrest DNA damage inducible (GADD) genes (GADD34, GADD45 and GADD153) in the different stages of melanoma recurrences and metastase s, and to identify any mutual consistencies in their expression pattern. Al l the cases of primary melanoma examined showed a reduced expression of DNA repair genes. These results demonstrate that disturbances of DNA repair be gin in the early stages of melanoma. No significant differences were found in the expression of these markers between cutaneous melanomas and their re currences and metastases (P > 0.05). Eighteen significant correlations betw een markers were found in the primary melanomas, and 10 significant correla tions were observed in the first recurrences of melanoma. In contrast, 27 s tatistically significant relationships were demonstrated in metastatic lymp h nodes. The different correlations found in primary and metastatic tumours confirmed the hypothetical difference in marker interaction in the diagnos tic groups investigated. Our results suggest that DNA repair genes may play an important role in the recurrence and metastasis of melanomas. (C) 2000 Lippincott Williams & Wilkins.