Apolipoprotein D expression in cutaneous malignant melanoma

Background and Objectives Apolipoprotein D (Apo D) is a protein component of the human plasma lipid transport system, and an androgen‐regulated protein in both breast and prostate cancer cell lines. Our goal was to evaluate the expression of Apo D in malignant cutaneous melanomas, as well as to assess its possible relationship to clinical and pathological parameters. Methods Apo D expression was analyzed in 32 paraffin‐embedded tissues from patients with invasive cutaneous malignant melanomas, in 8 samples from in situ melanoma, and in 10 samples from 10 benign lesions (4 dermal melanocytic nevi, 4 compound melanocytic nevi, and 2 dysplastic melanocytic nevi), using immunohistochemical techniques. Results The benign lesions were consistently negative for Apo D, whereas 3 of the 8 “in situ” melanomas (37.5%) and 12 of the 32 invasive melanomas (37.5%) showed positive immunostaining for Apo D. The percentage of Apo D‐positive tumors was significantly higher in nodular than in superficial spreading melanomas ( P  = 0.011) and in melanomas with vertical growth phase than in melanomas with radial growth phase ( P  = 0.02). In addition, the percentage of Apo D‐positive tumors was positively and significantly correlated with Clark's level of invasion ( P  = 0.046). Conclusions Apo D may be a new prognostic factor of unfavorable evolution in cutaneous malignant melanoma. J. Surg. Oncol. 2003;83:99–105. © 2003 Wiley‐Liss, Inc.