NOL7 facilitates melanoma progression and metastasis

Dear Editor,Metastasis is the cause of most fatalities in cancer patients and remains the phenomenon poorly understood mechanistically. Deciphering of the regulatory networks underlying the cancer cell metastasis is urgently needed. Nucleolar protein 7 (NOL7) has been reported to function as a tumor suppressor in cervical cancer.1 Our current study reveals a novel tumor-promoting capacity of NOL7 in melanoma. We first detected that NOL7 expression is upregulated in metastatic melanoma as compared with its expression at the primary site through isobaric tag for relative and absolute quantitation proteomic screening, further confirming this finding with the analysis of NOL7 protein and messenger RNA (mRNA) levels (Supplementary Fig. S1). Importantly, NOL7 expression increased with the disease progression from benign nevus to primary melanoma and further to metastatic melanoma (Fig. 1a and Supplementary Fig. S1d). Previous studies have shown that melanoma is commonly associated with the amplification of the chromosome region 6p, particularly 6p21–23, where the NOL7 gene resides, and that this region frequently undergoes heterozygous loss in cervical cancer.2 It might therefore be predicted that NOL7 exhibits a different expression pattern and plays different roles in melanoma and cervical cancer.