Level of a membrane-bound high-molecular-weight melanoma-associated antigen and a cytoplasmic melanoma-associated antigen in surgically removed tissues and in sera from patients with melanoma.

Utilizing double-determinant immunoassays (DDIAs), the high-molecular-weight melanoma-associated antigen (HMW-MAA) was detected only in fetal skin and in one nipple of 54 normal tissues from adults tested, while the cytoplasmic MAA recognized by the monoclonal antibody 465. 12S was found in most of the normal tissues tested. Among malignant lesions, the HMW-MAA was found in melanomas, astrocytomas, and skin carcinomas; the cytoplasmic MAA was found in all of the malignant lesions tested, even those which originated from normal tissues without detectable cytoplasmic MAA. The levels of the HMW-MAA and of the cytoplasmic MAA showed marked variations in malignant lesions removed from various patients, as well as in autologous metastatic lesions removed from four patients with melanoma. No relationship was found between the degree of expression of the two MAA analyzed and the clinical stage of the disease. Both types of MAA were found in sera from patients with melanoma or other types of cancers, as well as in sera from healthy donors. The level of the HMW-MAA tended to be higher in patients with Stage IV melanoma.