Long term follow-up of c-myc, p53 and proliferation measurements in malignant melanoma.

We report a prospective study examining the prognostic significance of the c-myc oncoprotein, p53 tumour suppressor gene and proliferation rate measurements in malignant melanoma. Flow cytometry (FCM) was used to measure the expression of c-myc, p53 and proliferation parameters in patients who had received an injection of the thymidine analogue bromodeoxyuridine prior to surgery. Sixty-seven patients had successful FCM measurements of the three parameters. c-myc was detected in 97% of patients with a median cell positivity of 62%. The median p53 positivity was 13%. The median potential doubling time (T(pot)) of the tumours wasf 9.4 days. In univariate analysis, each of the parameters showed an association with survival in metatstatic disease with rapid proliferation (p=0.006) or overexpression of c-myc (p=0.038) related to poor survival whereas increased positivity for p53 predicted better survival (p=0.013). These data indicate that laser cytometric technology can be used to obtain quantitative data on oncoproteins expression and cell proliferation rates in clinical samples of malignant melanoma.