SDHB and head and neck squamous cell carcinoma: The scrutiny of TCGA's RNA sequencing data for the tumour tissues indicated putative C>U RNA editing of SDHB open reading frame (ORF) at c.136, but at no other site, in 30.2%, 26.4% and 9.6% of 298 primary head and neck squamous cell carcinoma, 220 lung adenocarcinoma and 187 secondary skin cutaneous melanoma cases that were examined, respectively (Fig. 4a).