Gene expression analysis of recurrent metastatic melanoma lesions

In this study, we sought to indentify stable individual traits in developing metastatic melanoma, assess their stability in time, and analyze typical dynamics and common trends of genomic changes in individual cases of late stage metastatic cancer. To this end, we compared consecutive recurrent metastases developed by a special group of eight individuals with advanced metastatic melanoma, all developing several recurrent metastases over several months to years of natural disease evolution. Twenty-six recurrent melanoma metastases were surgically isolated from 8 patients experiencing relapse after one or more successful treatment intervention(s) with no signs of residual disease. Patients experiencing recurrent metastases were labeled with capital letters; “A”, “B”, “C”, etc., their subsequent metastases as “A/1”, “A/2”, “B/1”, “B/2”, etc., while synchronous metastases in a given patient were labeled as “A/1a”, “A/1b” etc. Another 22 melanoma cell lines isolated and maintained as above were expanded from melanoma patients with rapid disease curse, for whom only one metastasis was available. As no extended follow up was possible in these cases, the cell lines are considered representative of random time points in the natural course of metastatic melanoma. These cell lines were labeled with Arabic numbers, as “1”, “2”, ”3”, etc