Expression of metallothionein in oral squamous cell carcinoma: A systematic review.

Free radicals are chemical particles containing one or more unpaired electrons, which may be part of the molecule making them highly reactive species. The free radicals are also known to play a dual role in biological systems, as they can be either beneficial or harmful. It has been proven that there are numerous mechanisms participating in the protection of a cell against free radicals. In this systematic review, we have reviewed metallothioneins (MTs) which are a small, cysteinerich and heavy metalbinding protein, that participates in an array of protective stress responses. The aim of this study was to systematically evaluate the role of MT in oral squamous cell carcinoma (OSCC). In this systematic review, we have found that in 9 studies involving 1340 cases and 542 controls concluded that MT was found to be present in the cytoplasm as well as the nucleus of the tumor tissue in 66.6% of the articles using immunohistochemistry and 11.1% of the articles reported the mosaic pattern of expression of MT in OSCC.