Microsatellite analysis at 1p36.3 in malignant melanoma of the skin: fine mapping in search of a possible tumour suppressor gene region.

Deletions in 1p36 in malignant melanoma have been found in high percentages in nodular melanomas and melanoma metastases. Despite many efforts, no candidate tumour suppressor gene associated with malignant melanoma has so far been found in this region. To further determine a possible tumour suppressor gene locus, we carried out a deletion mapping of chromosome 1p36 at nine microsatellite loci in 74 malignant melanomas. Loss of heterozygosity (LOH) in this region was found in 77% of nodular melanomas (NMs), 86% of metastatic melanomas, but only 20% of superficial spreading melanomas (SSMs). Regarding the allelic losses, the nodular and metastatic melanoma samples could be divided into three groups: one showing LOH at the more telomeric loci D1S243 and D1S468 (1p36.33), one displaying allelic loss at the more centromeric loci D1S214 and D1S253 (1p36.32-31) and one with LOH over all informative loci between D1S243 and D1S160. We did not find any significant correlation between a deletion in any of the investigated loci and the survival data of the patients. However, our results confine the deleted region in malignant melanoma to a very small area around 1p36.32, thus facilitating the search for the tumour suppressor gene with importance in malignant melanoma.