Association of high molecular weight melanoma-associated antigen expression in primary acral lentiginous melanoma lesions with poor prognosis.

In a recent study we detected marked differences in the antigenic profile of acral lentiginous melanoma (ALM) and nodular melanoma lesions. Furthermore, we showed that the human high molecular weight melanoma-associated antigen (HMW-MAA) is expressed with a significantly higher frequency in metastatic than in primary ALM lesions. Because of the potential role of HMW-MAA in the metastatic process of melanoma cells, in the present investigation we tested whether HMW-MAA represents a useful prognostic marker in ALM. Primary ALM lesions removed from 32 patients were stained with anti-HMW-MAA monoclonal antibody (mAb) in an immunoperoxidase reaction. The results were correlated with the expression of other markers defined by mAb, with clinical parameters of the disease, and with histopathological characteristics of the lesions. Only 9 of the 32 primary ALM lesions tested were stained by anti-HMW-MAA mAb. Expression of HMW-MAA was the only variable associated with patients' survival and disease-free survival. Both were significantly shorter in patients with HMW-MAA expression in their primary lesions. These results suggest that HMW-MAA may represent a novel prognostic marker in ALM, since phenotyping of primary ALM lesions with anti-HMW-MAA mAb may provide information about the prognosis of the disease which cannot be obtained with known prognostic parameters.