Expression of nm23-H1 protein indicated favorable prognosis, suggesting that the absence of nm23-H1 protein expression was significantly associated with lymph-node metastasis, recurrence and distant metastasis in NPC.
Nometastatic gene 23-H1 (NME1, also known as nm23-H1) is a wide-spectrum tumor metastasis suppressor gene that plays an important role in suppressing the invasion and metastasis of tumor cells.
Expression of the E7 oncoprotein in HaCaT cells induces modified keratinocyte proliferation and differentiation patterns, and leads to down-modulation and functional inactivation of the metastasis suppressor Nm23-H1 protein.
The nm23 gene is thought to play a role as an inhibitor of metastatic progression in several human cancers and its down-regulation has been associated with increased metastasis and reduced survival in some studies, though not in others.
The data indicate that DNA methylation inhibitors can directly or indirectly cause both elevation of Nm23-H1 expression and decreased function in one aspect of metastasis, motility.
This overexpression was lost, however, in some advanced cases: 89% and 81% of TNM (tumour, node, metastases) stages 0-II showed Nm23-H1 and -H2 overexpression, respectively, which significantly differed from 47% and 38% of stage III-IV tumours.
The MSGs KISS1, KAI1, MKK4/7 and Nm23-H1 promote tumor dormancy at the metastatic site, since tumor cells with induced expression of these MSGs disseminate, but do not form overt metastases in the secondary organ throughout the duration of a metastasis assay.
These results suggest that nm23 may not be the metastasis suppressor gene and the alteration of this gene not play an important role in the process of metastasis of gastric cancer.
To determine whether the nm23 genes could have a metastasis-suppressor function in non-small-cell lung carcinoma (NSCLC), pulmonary sarcoma and carcinoids, we analysed both nm23-HI and nm23-H2 mRNA levels in 37 tumor samples obtained from patients who underwent potentially curative resection between 1986 and 1990, and in 4 metastatic tumors obtained from autopsy.
It was found that patients developing metastases during the first 2 years after diagnosis had significantly lower levels of tumor nm23 expression (56% of the mean value) compared to patients with less aggressive disease (164%) (P < 0.0004).
The NM23-H1 positive group showed lower frequency of lymph node metastasis, and a better grading than the NM23-H1 negative group supporting the role of NM23-H1 as metastasis suppressor factor which may be useful for predicting tumor metastasis in OSCC.