Correlation of Ki-67 expression in cutaneous primary melanoma with prognosis in a prospective study: different correlation according to thickness.
BACKGROUND
The proliferative activity of melanoma cells, evaluated as MIB-1 immunoreactivity against a Ki-67 epitope, has been considered an indicator of poor prognosis in thick primary melanomas.


OBJECTIVE
The aim of the study was to assess the correlation between the growth fraction of primary melanomas, assessed by means of Ki-67 immunoreactivity, and metastatic relapse.


METHODS
Ki-67 reactivity in primary melanomas was evaluated as at least 5% of positive neoplastic cells and was assessed on fresh specimens of 55 primary lesions at the time of excision. Such reactivity was correlated with metastatic relapse of patients in a prospective study, by means of multivariate Cox regression models (follow-up, 3-120 months).


RESULTS
Ki-67 immunoreactivity was associated with increasing thickness (P =.003). Positive correlation was found between Ki-67 reactivity and metastatic dissemination in primary melanomas less than 1.5 mm thick (n = 23; mean thickness, 0.75 +/- 0.3 mm; P =.002). On the contrary, a negative correlation was found between Ki-67 reactivity and metastatic activity in primary melanomas thicker than 1.5 mm (n = 32; mean thickness, 4.0 +/- 1.6 mm; P =.019).


CONCLUSIONS
Ki-67 proliferative activity appears to be a possible predictor of metastasis in primary melanomas, in particular, an indicator of poor prognosis in lesions less than 1.5 mm thick.
Moretti
S
S
Second Dermatology Unit, S.M. Nuova Hospital, Azienda Sanitaria di Firenze, Italy. silviamore@tin.it
Spallanzani
A
A
Chiarugi
A
A
Fabiani
M
M
Pinzi
C
C
D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis*; D008297:Male; D008545:Melanoma / Q000276:immunology* / Q000473:pathology / Q000556:secondary; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D012878:Skin Neoplasms / Q000276:immunology* / Q000473:pathology
D019394:Ki-67 Antigen