Objective. To understanding the molecular mechanisms in invasion and metastasis of the ovarian carcinoma

we investigate a novel candidate metastasis-associated gene （ MTA1） and nm23Hl mRNA expression and mutation in ovarian carcinoma.Methods. Twenty primary ovarian carcinoma specimens

20 corresponding lymph nodes and 8 normal ovarian was examined for mRNA expression and mutation of MTA1 and nm23Hl genes by reverse-transcription ploymerase chain reaction （RT-PCR） and RT-PCR-SSCP analysis. The level of the expression was determined by the relative optic desity （ROD） of the PCR products.Results. The frequency of MAT1 overexpression was 100% （7/7） in primary ovarian carcinoma with metastasis but only 38.5% （5/13） in those without metastasis （P=0.0103）. Overexpression of MAT1 was observed in 87.5%（6/7） of lymph nodes with metastasis but only 23%（3/13） of lymph nodes without metastasis （P=0.0118）. In contrast with MAT1

low expression of nm23Hl mRNA was seen in 7 of 7 o-varian carcinoma with metastasis but only in 4 of 13（30%） of those without metastassis （P=0.0043）. Low nm23Hl expression was also seen in 7 of 7 lymph nodes with metastasis but only in 5 of 13 （38.5%） nonmetastatic lymph nodes （P=0.0102）. The ROD ratio of MAT1 to nm23Hl increased with the development of metastasis. No mutation of MAT1 and nm23Hl genes was found by SSCP analysis.Conclusion. The mRNA expression of MTA1 and nm23Hl is positively and negatively correlated with lymph node metastasis

respectively. Expression abnormalities but not mutation of the two genes are frequent events related to lymph node metastasis of ovarian cancer.