Antigenic phenotype of radial growth phase melanomas with or without a vertical growth phase portion.

Abstract

The expression of 4 melanoma-associated antigens and of class I and II HLA antigens was investigated in 12 superficial spreading melanomas (SSM) and in 8 SSM with a vertical growth pattern portion (SS + NM) by the use of monoclonal antibodies and an indirect immunoperoxidase procedure. Monoclonal antibodies 225.28, 763.74, CL.203, VF19-LL217, Q5-13, W6-32 and anti-HLA-DR, were used. Each antigen was more frequently expressed by SS + NM on the whole than by SSM and also by the radial growth pattern portions of SS + NM than by SSM. Vertical growth pattern portions of SS + NM were not antigenically similar to radial growth pattern portions in the same tumors. The high frequency of antigen expression in radial growth pattern melanomas seems to be associated with the appearance of a more invasive cell population.