Programmed cell death (apoptosis) is now recognized as an important factor in tumour growth. Bcl-2 is an oncogene which promotes tumour progression by specifically inhibiting programmed cell death. Bcl-2 oncoprotein was measured using flow cytometry in 42 surgically excised regional lymph node metastases from patients with a median follow-up of 45 months. Fifteen patients in the study were found to have bcl-2 expression which was associated with significantly shorter survival (log-rank test, P<0.002). In addition, multivariate analysis confirmed the predictive value of bcl-2 independent of other established prognostic markers (chi(2)=7.02, P<0.01). Oncogenic control of programmed cell death is therefore important in melanoma progression and bcl-2 measurement provides a useful marker of prognosis for regional lymph node metastases.