[545] Human Endogenous Retrovirus Type K (HERV-K) Envelope Glycoprotein Is Expressed in Melanoma

P Yan, D Whittemore, J Byrd, E Uzoigwe, R Rapini, G Johanning, F Wang-Johanning. University of Texas Health Science Center, Houston, TX; UT M.D. Anderson Cancer Center, Houston, TX

Background: Expression of human endogenous retrovirus K (HERV-K) has been reported in melanomas and melanoma cell lines, and enhanced antibody against HERV-K has been shown to be present in sera from melanoma patients. Given its limited expression, it is proposed that HERV-K can potentially serve as a useful marker for melanoma. The aim of this study was to determine whether HERV-K surface glycoprotein is expressed in malignant melanoma (MM) and other melanocytic lesions using HERV-K env-specific 6H5 monoclonal antibody.
Design: Slides from 71 tissues were examined. Staining was performed using monoclonal antibody 6H5, prepared against HERV-K surface glycoprotein, and scored as 0 to 3+.
Results: There was a progressive increase in staining for HERV-K env among the primary lesions. Benign nevi were negative for HERV-K, and dysplastic nevi were mostly negative, with only 1/8 mildly dysplastic nevi (1+) and 2/4 moderately dysplastic nevi (2+) stained, only in the junctional component, with dermal nests negative. There was a significant difference (p<0.0001) in staining score between in situ melanoma (8 lentigo maligna & 4 malignant melanoma in situ) vs. the non-nodular MM group (6 lentigo maligna melanoma & 13 superficial spreading MM). There was less staining (p<0.05) of the lentigo maligna melanoma sub-group vs. the superficial spreading MM sub-group and also vs. the nodular melanoma group, but no significant differences between any other invasive melanoma groups. In all MM groups, the staining (mostly 2+ or 3+) extended and involved diffusely the dermal component. Though there was less intense staining in metastatic MM than in unpaired primary melanomas (p=0.007), all metastases were positive for HERV-K env glycoprotein.

TissuePositive / nscore ± SEM
Benign Nevi0/100
Dysplastic Nevi3/120.42±0.23
In Situ Melanoma8/120.67±0.49
Non-nodular Malignant Melanoma17/191.95±0.91
Nodular Malignant Melanoma14/142.29±0.61

Conclusions: HERV-K envelope glycoprotein is detected in melanoma tissues and that expression is associated with melanoma progression. Since activation of latent HERV could be linked with several cancers including melanoma, the expression of immunologically detectable surface glycoprotein might serve as a vaccine target.
Category: Dermatopathology

Monday, March 22, 2010 2:00 PM

Platform Session: Section F, Monday Afternoon


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