Immunohistochemical expression of nm23 in primary invasive malignant melanoma is predictive of survival outcome.

The objective of this study was to determine the utility of nm23 as an immunohistochemical indicator of prognosis in a large series (157 cases) of malignant melanoma and also in two subsets within this group: stage 1 tumours, whether in radial or vertical growth phase (140 cases); and stage 1 tumours in which a vertical growth phase component was positively identified (123 cases). A secondary objective was to explore the relationship between the immunohistochemical expression of nm23 and established clinical and histological indicators of prognosis in each of these three groups. In all groups it was found that strong immunoreactivity correlated positively with survival and inversely with indicators of poor prognosis, in keeping with transfection and mRNA studies and also with many immunohistochemical studies of other tumour types. That these findings are at variance with earlier reported immunohistochemical studies of melanoma highlights the importance of large case numbers of primary invasive tumours in studies which set out to explore the relationship between immunoreactivity and survival.