ACCUMULATION OF P53 PROTEIN IN HUMAN-MALIGNANT MELANOMA - RELATIONSHIPS TO CLINICAL OUTCOME

Paraffin-embedded tissue from the primary tumours of 116 patients with malignant melanoma, and in 40 cases also from corresponding metastase s, were examined for accumulation of p53 protein. The fraction of tumo urs with positive p53 immunostaining was 13% in the least invasive and 36% in the most invasive primary lesions and 48% in the metastases. W here comparisons could be made, both the level and pattern of p53 immu noreactivity were the same in the primary and metastatic tumours. Nine (50%) patients with p53-positive and 34 (39%) with p53-negative prima ries relapsed during the first 5 years, but no difference in disease-f ree period was observed between the two groups. However, an overall lo nger survival time was observed among patients with p53-positive prima ries, especially for those with tumours less invasive than 3.0 mm. Not ably, all 11 patients in this group were alive 5 years after diagnosis of the disease, whereas 15 out of 70 (21%) patients with p53-negative tumours died in same period. The results show tht an increased level of p53 protein does not indicate increased degree of malignancy in mel anoma, but rather suggests a more favourable disease progression.