An analysis of p16 protein expression in sporadic malignant melanoma.
Inactivation of p16 tumour suppressor gene has been reported frequently in melanoma cell lines, and mutations have been detected in familial melanoma kindreds. The aim of this study was to assess the role of p16 inactivation in melanocytic progression by measuring the level of p16 protein in a range of sporadic, benign and malignant melanocytic lesions. Using dual parameter flow cytometry, p16 protein expression was measured in 30 benign melanocytic naevi, 38 primary and 51 metastatic melanomas. A high level of p16 expression was demonstrated in benign melanocytic naevi (96% median nuclear positivity), with a significant reduction in primary melanomas (69%, P < 0.001). The median nuclear positivity of primary melanomas was significantly higher (P < 0.03) than the level of expression in metastatic lesions (median positivity 37%). A progressive loss of p16 expression was demonstrated from benign melanocytic naevi through to primary and metastatic lesions. These data suggest that loss of p16 protein expression is not only associated with the early transformation of benign lesions, but also with the later stages of malignant progression.
RAFT Institute of Plastic Surgery, Mt Vernon Hospital, Northwood, Middlesex, UK.
R
R
Grover
J S
JS
Chana
G D
GD
Wilson
P I
PI
Richman
R
R
Sanders
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000276:immunology / Q000378:metabolism*; D018450:Disease Progression; D005260:Female; D005434:Flow Cytometry; D016147:Genes, Tumor Suppressor; D006801:Humans; D007106:Immune Sera; D008297:Male; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000556:secondary; D008875:Middle Aged; D009508:Nevus, Pigmented / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009687:Nuclear Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015996:Survival Rate; D014018:Tissue Distribution
D019941:Cyclin-Dependent Kinase Inhibitor p16; D007106:Immune Sera; D009687:Nuclear Proteins