Letter to the editor: is HIF-1alpha a viable prognostic indicator in OSCC? A critical review of a meta-analysis study.

The study performed by Zhou et al. (World J Surg Oncol 15:104, 2017) titled "Clinical and prognostic significance of HIF-1alpha overexpression in oral squamous cell carcinoma: a meta-analysis" attempts to highlight hypoxia-inducible factor-1 alpha as a possible prognostic marker in oral squamous cell carcinoma (OSCC). We would like to underline a few points which may affect such a conclusion. The correlations between HIF-1alpha expression and tumour size as well as tumour stage are debatable. Further, the subgroup analysis incorporating Australia and Europe into a single subgroup limits the viability of the prognostic analysis of HIF-1alpha. We also suggest future studies in the same research area to analyse head and neck squamous cell carcinoma instead of OSCC, to ameliorate the limitations encountered by Zhou et al., due to the scarcity of relevant clinical data and a low number of studies about OSCC.