NPAS2 and skin cancer: These contradictions may be explained by the fact that the expression level and function of NPAS2 is tumor type specific, which was further supported by our analysis for the prognostic value of NPAS2 in multiple types of cancer from the PrognoScan (a database for meta-analysis of the prognostic value of genes) (Supplementary Table 5), indicating that NPAS2 expression is a favorable prognostic factor in breast and ovarian cancer but is a poor prognosis factor in lung, soft tissue, brain and skin cancers.