Differential expression of growth arrest, DNA damage genes and tumour suppressor gene p53 in naevi and malignant melanomas.

Twenty nine benign naevi and 59 melanomas of different Clark level and locations were stained immunohistochemically for the presence of p53 and 3 members of Growth Arrest. DNA Damage inducible family: GADD 34, GADD 45 and GADD 153. All naevi were p53 negative and highly GADD positive. Differences in the expression of all 3 GADD proteins between naevi and melanomas were highly significant (p = 0.0001). The expression of p53 increased and the expression of GADD proteins decreased with the Clark level of melanoma thickness. The survival time of patients correlated negatively with p53 positivity and positively with GADD 45 and 153 expression. Prognostic significance for GADD 34 was not found. Our conclusion is that GADD proteins play an important role in the malignant transformation of naevus to melanoma and GADD 45 and GADD 153 proteins can influence patient survival.