The Role of nm23-H1 Gene in Urologic Cancer (II): Expression and Mutation of nm23-H1 Gene in Urothelial Cancer

Moon, Woo Chul; Kee, Young Jin; Seo, Kyung Keun

Abstract

BACKGROUND AND PURPOSE: We had previously demonstrated by immunohistochemical study (IHS) that nm23-H1 gene may play an important role in disease prognosis as well as its participation in metastasis of urothelial cancer. The purpose of present study was 1) to reexamine the role of nm23-H1 gene in urothelial cancers at molecular level, 2) to identify the molecular mechanism of decreased immunoreactivity for nm23-H1 protein in metastatic urothelial cancers, and 3) to identify whether IHS is reliable in studying the expression of nm23-H1.
MATERIALS AND METHODS
We studied expression level and mutation profiles of nm23-H1 gene in 25 fresh surgical specimens of urothelial cancer by reverse transcription polymerase chain reaction(RT-PCR)-Southern blotting analysis, and PCR of genomic DNA followed by single strand conformation polymorphism and sequencing analysis. The results of RT-PCR-Southern blotting were comparatively analyzed with those of IHS.
RESULTS
mRNA transcript levels of nm23-H1 gene were significantly decreased in tumor tissues with metastasis as compared with those without metastasis. The transcript levels of nm23-H1 gene were also significantly decreased in metastatic tumor tissues as compared with primary tumor tissues. Point mutation of nm23-H1 gene was detected in only 1 of 13 urothelial cancer tissues with metastasis, whereas, mutation was observed in none of those without metastasis. The results of IHS corresponded with those of RT-PCR-Southern blotting analysis in 23 of 25 specimens.
CONCLUSIONS
The nm23-H1 gene may play an important role in metastasis of urothelial cancer. Decreased transcription at mRNA level may be a major molecular mechanism of loss of immunoreactivity for nm23-H1 protein in urothelial cancer. IHS used in the present study may be a clinically useful method to study the expression of nm23-H1 and to predict metastasis potential and prognosis of urothelial cancers.