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We recently reported one interesting case showing mutation-free c-KIT proto-oncogene overexpression and paradoxical hypermethylation in 54 cases of primary squamous cell carcinoma of uterine cervix (SCC). However, its molecular mechanisms still remain unknown. We propose the hypothesis that increased methylation at the CpG islands on the promoter near the first exon region might interfere with the binding of CTCF repressor with c-KIT promoter that regulates c-KIT proto-oncogene expression in such case. Further studies focusing on the status of epigenetic modifications of mutation-free c-KIT (+) tumors are encouraged.

Dysregulation of microRNAs has a critical role in cancer progression. Here we identify an intronic microRNA, miR-135b that is upregulated in highly invasive non-small-cell lung cancer cells. Expression of miR-135b enhances cancer cell invasive and migratory abilities in vitro and promotes cancer metastasis in vivo, while specific inhibition of miR-135b by a miR-135b-specific molecular sponge and antagomirs suppresses cancer cell invasion, orthotopic lung tumour growth and metastasis in a mouse model. miR-135b targets multiple key components in the Hippo pathway, including LATS2, β-TrCP and NDR2, as well as LZTS1. Expression of miR-135b, LZTS1, LATS2 and nuclear TAZ predicts poor outcomes of non-small-cell lung cancer. We find that miR-135b is dually regulated by DNA demethylation and nuclear factor-kappaB signalling, implying that abnormal expression of miR-135b in cancer may result from inflammatory and epigenetic modulations. We conclude that miR-135b is an oncogenic microRNA and a potential therapeutic target for non-small-cell lung cancer.