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.
|Tissue||Positive / n||score ± SEM|
|In Situ Melanoma||8/12||0.67±0.49|
|Non-nodular Malignant Melanoma||17/19||1.95±0.91|
|Nodular Malignant Melanoma||14/14||2.29±0.61|