To elucidate the relevance of the qualitative changes of the nm23 genes to progression of ovarian carcinoma and/or to nm23 expression levels of the tumour, 41 samples of epithelial ovarian tumours [three benign, three low malignant potential (LMP), and 35 frankly malignant tumours] were studied for mutation of the nm23-H1 and the nm23-H2 genes using single-strand conformational polymorphism (SSCP) analysis. This evidence concerns the gene NME2 and neoplasm.