Large deletions of chromosome 9p in cutaneous malignant melanoma identify patients with a high risk of developing metastases

Cutaneous malignant melanoma (CMM) is an aggressive tumour with a high meta static potential. Deletions of chromosome 9p have been detected in CMM, som e of which involve the CDKN2A/p14(ARF) genes. Loss of heterozygosity (LOH) of 16 microsatellite markers on 9p and mutations in the CDKN2A/p14(ARF) gen es had been previously studied in 32 melanoma patients by our group. 9p del etions were detected in 15 primary tumours (45.5%) and are here correlated with the clinical outcome over 5 years and compared with classical prognost ic factors. Eight of the 32 patients developed metastases (25%). The metast ases were all detected within 768 days of the initial diagnosis. The patien ts without metastases were last monitored at least 1621 days after diagnosi s. None of the 21 patients with more than eight microsatellites conserved d eveloped metastases, whereas all of the eight patients who developed metast ases had eight or more markers deleted. The sensitivity of this analysis to predict metastases was 100% (specificity 84%), whereas the sensitivity for the same sample using a Breslow thickness > 3 mm was 62.5% (specificity 68 %). LOH of eight or more of the 9p microsatellite markers is therefore a us eful prognostic factor to predict the development of metastases in the firs t 4.4-6.3 years (1621-2294 days), (C) 2000 Lippincott Williams & Wilkins.