Overexpression of nm23-H4 RNA in colorectal and renal tumours.

A new member of the nm23 gene family, designated nm23-H4, was cloned recently. Nm23-H4 is a mitochondrial protein. To determine whether nm23-H4 could have a function in tumour progression like nm23-H1 or nm23-H2, we analysed nm23-H4 expression in 18 renal tumours and 42 colorectal carcinomas obtained from patients who underwent curative resection. As compared to the corresponding healthy tissue, 14 renal tumours and 41 colorectal carcinomas showed increased nm23-H4 mRNA expression. While the increase was only moderate in renal cell carcinoma, a strong overexpression of nm23-H4 was noted in most colorectal carcinomas, possibly indicating a role of this gene in tumour genesis. The nm23-H4 transcript levels did not correlate with tumour stage, grade of differentiation or lymph node involvement.