PROGNOSTIC-SIGNIFICANCE OF ALLELIC LOSSES IN PRIMARY MELANOMA

Loss of genetic material, including loss of loci on chromosome arms 6q , 9p, and 10q, occurs frequently in cutaneous melanoma but infrequentl y in benign melanocytic nevi or other melanocytic lesions, suggesting that these genetic alterations are important in the development and pr ogression of melanoma, To examine whether allelic loss is of prognosti c importance in melanoma, disease-free survival was related to loss of heterozygosity on 6q, 9p and 10q in 83 individuals with sporadic prim ary cutaneous melanoma, Loss of chromosome arms 6q and 10q were each s ignificantly associated with a poorer clinical outcome (P = 0.013 and P = 0.001 respectively). In a subgroup of 41 subjects whose primary tu mours mere allelotyped, the fractional allelic loss (FAL) at 39 autoso mal arms also significantly correlated with disease-free survival (P = 0.013), with an increase in FAL associated with a poorer outcome; thi s association remained significant when controlled for tumour thicknes s (P = 0.035). In addition, a greater proportion of cells were immunop ositive for Ki67 antigen, p53 and p21(WAF1) protein in the primary mel anomas than in the benign melanocytic nevi, however, only p53 overexpr ession was significantly associated with improved survival (P = 0.041) .