Can tissue biomarkers be used to determine the prognosis of oral leukoplakia lesions with regards to malignant transformation?

Design Systematic review looking at published studies which aimed to identify human tissue biomarkers which could predict malignant transformation of oral leukoplakia (OL) lesions.Case/control selection Articles were identified from PubMed, EBSCO and Cochrane library databases using combinations of keywords. Randomised clinical trials, case-control studies and prospective and retrospective cohort studies were included. All studies had to include follow-up data. There were no restrictions regarding gender, age groups, geographic origin, or year of publication. The selection process involved two of the researchers independently analysing titles and abstracts to identify articles for full-text reading. The same authors then read the articles identified for full-text reading, applying the eligibility criteria. If there was a disagreement with regards to the selection, a discussion was had until a consensus was reached.Data analysis Qualitative data was presented as reported from the primary studies. Quantitative analysis was not carried out due to the high heterogeneity across the studies.Results Forty-six studies were included within the systematic review. These studies identified a total of 3,783 patients with OL, of which 1,047 went on to develop oral cancer, giving an average malignant transformation incidence of 27.6%. Forty-nine different tissue biomarkers were evaluated among the included studies, with the p53 and podoplanin proteins and loss of heterozygosity the most frequently discussed.Conclusions Of the biomarkers studied, podoplanin and chromosomal loci abnormalities (such as loss of heterozygosity) would appear the most promising in being able to predict malignant transformation of OL lesions; however, further research is required.