Oral cancer generally progresses from precancerous lesions such as leukoplakia (LK), lichen planus (LP) and oral submucous fibrosis (OSMF). Since few of these precancers progress to cancers; it is worth to identify biological molecules that may play important roles in progression. Here, expression deregulation of 7 miRNAs (mir204, mir31, mir31*, mir133a, mir7, mir206 and mir1293) and their possible target genes in 23 cancers, 18 LK, 12 LP, 23 OSMF tissues compared to 20 healthy tissues was determined by qPCR method. Expression of mir7, mir31, mir31* and mir1293 was upregulated and that of mir133a, mir204 and mir206 was downregulated in cancer. Expression of most of these miRNAs was also upregulated in LK and LP tissues but not in OSMF. Expression deregulation of some of the target genes was also determined in cancer, LK and LP tissues. Significant upregulation of mir31 and downregulation of its target gene, CXCL12, in cancer, LK and LP tissues suggest their importance in progression of precancer to cancer. Expression upregulation of mir31 was also validated using GEO data sets. Although sample size is low, novelty of this work lies in studying expression deregulation of miRNAs and target genes in oral cancer and three types of precancerous lesions.
The concept "field effect in cancer" originated in 1953, from the histopathological observations of Slaughter and colleagues regarding the occurrence of multiple primary oral squamous cell carcinomas and their local recurrences. There are two fundamental theories regarding the development of oral field cancerization (OFC) which includes the "classical" and the "clonal" mechanism. The classical view hypothesizes that the entire epithelial surface of the upper aerodigestive tract has an increased risk for the development of premalignant disorders because of multiple genetic abnormalities in the whole tissue region; owing to prolonged exposures of susceptible carcinogens as a result of tobacco or alcohol consumption. While the clonal theory believes that there always exists a field with genetically altered cells having a high risk of developing premalignant and malignant disorders. Here, the developing separate tumors from a genetically individually altered stem cell in the extended field, share the same clonal origin, and some degree of genetic similarity. Modern molecular and histological technologies exploring the tissue abnormalities in OFC have been performed. Herein, we have briefly discussed regarding the concepts of field cancerization along with the various diagnostic molecular techniques and the therapeutic aspects.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.