Prognostic value of Ki-67 expression in localized cutaneous malignant melanoma.
BACKGROUND
The proliferative activity of some tumors is related to the development of metastatic disease and survival. Thus it could be used as a potential prognostic variable.


OBJECTIVE
The purpose of this study was to determine the prognostic value of the Ki-67 index and of a "proliferation-based prognostic index" (PBPI, derived as tumor thickness x Ki-67 index/100) in localized cutaneous malignant melanoma (CMM).


METHODS
The Ki-67 index (percent of total tumor nuclei) was determined in a series of 84 localized CMMs, with the use of the alkaline phosphatase-antialkaline phosphatase labeling method in formalin-fixed, paraffin-embedded material, and was correlated with other prognostic variables. Survival analysis was performed to determine whether the Ki-67 index and the PBPI could be predictive of metastatic spread or recurrent disease. A stratified analysis of these two parameters according to the tumor thickness was done.


RESULTS
An association among the Ki-67 index and location, Clark level, tumor thickness and stage, and prognostic index was detected. Increased Ki-67 index and PBPI were associated with poorer overall survival (P =.03 and P <.0001, respectively) and disease-free survival (P =.01 and P <.0001, respectively). However, after stratification for thickness, only the PBPI showed independent prognostic significance, restricted to tumors thicker than 4 mm (P =. 03).


CONCLUSIONS
The determination of the PBPI in CMM conveys prognostic information for localized thick (>4 mm) CMM, identifying two groups of patients with distinct outcome.
Henrique
R
R
Department of Pathology, The Portuguese Cancer Institute-Porto Regional Centre, Portugal. rmfhenrique@netc.pt
Azevedo
R
R
Bento
M J
MJ
Domingues
J C
JC
Silva
C
C
Jerónimo
C
C
D015415:Biomarkers / Q000032:analysis; D001707:Biopsy, Needle; D016009:Chi-Square Distribution; D046508:Culture Techniques; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis*; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000276:immunology / Q000473:pathology* / Q000556:secondary; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000175:diagnosis / Q000276:immunology / Q000473:pathology*
D015415:Biomarkers; D019394:Ki-67 Antigen