Fingerprinting genomic instability in oral submucous fibrosis

Background: Oral submucous fibrosis (OSF) is a high‐risk pre‐cancerous condition where 7–13% of these patients develop head and neck squamous cell carcinoma (HNSCC). To date there is no cancer predictive markers for OSF patients. Genomic instability hallmarks early genetic events during malignant transformation causing loss of heterozygosity (LOH) and chromosomal copy number abnormality. However, to date there is no study on genomic instability in OSF. Although this condition is known as a high‐risk pre‐cancerous condition, there is no data regarding the genomic status of this disease in terms of genetic susceptibility to malignant transformation. Methods: In this study, we investigated the existence of genetic signatures for carcinogenesis in OSF. We employed the high‐resolution genome‐wide Affymetrix Mapping single nucleotide polymorphism microarray technique to ‘fingerprint’ global genomic instability in the form of LOH in 15 patient‐matched OSF–blood genomic DNA samples. Results: This rapid high‐resolution mapping technique has revealed for the first time that a small number of discrete hot‐spot LOH loci appeared in 47–53% of the OSF tissues studied. Many of these LOH loci were previously identified regions of genomic instability associated with carcinogenesis of the HNSCC. Conclusion: To our knowledge, this is the first evidence that genomic instability in the form of LOH is present in OSF. We hypothesize that the genomic instability detected in OSF may play an important role in malignant transformation. Further functional association studies on these putative genes may reveal potential predictive oral cancer markers for OSF patients.