Expression and significance of Nodal in human cancers: a meta-analysis

Cancer is a global and growing problem. Nodal, which has been showed to be involved in occurrence and development of cancers, is an important embryonic morphogen. The aim of this study was to evaluate the significance of Nodal expression in human cancers based on the published related articles. Online databases were searched to retrieve relevant articles published between 2000 and 2015. The odds ratio (OR) with its 95% confident intervals (CI) were employed to calculate the strength of significance. Finally, a total of 11 articles were screened out, including 801 cancer patients and 372 healthy controls. Nine kinds of cancers were contained, and Nodal was detected in 56.7% of all participants (665/1173). Overall, our result found that Nodal was highly expressed in cancer patients than that in healthy controls, indicating that Nodal expression was significantly associated with cancers progression (OR = 21.72, 95% CI = 9.94-47.46, P < 0.00001). Subgroup analysis showed that Nodal expression was significantly corrected with high WHO grade of human cancers (III+IV versus I+II: OR = 2.46, 95% CI = 1.63-3.71, P < 0.00001). This significant relationship was also found in tumor size, differentiation degree, not observed in gender, age and lymphatic metastasis status of patients with all studied cancers in this meta-analysis. In conclusion, our results demonstrated that Nodal might be implicated in cancer progression, suggesting that it was a potential biomarker and therapeutic target for cancers.