Method: This study used gene expression profiling (GeneChip® U133-plus-2.0) to compare molecular divergence between biopsies radiating out from tumour to WL and NBI defined surgical margins in 18 patients with OSCC.
Result: Relative to tumour core, the numbers of differentially expressed genes was 25.6% higher for NBI (4387) than for WL (3266), signifying that NBI placed margins into less involved tissue than WL examination, with fewer molecular abnormalities. Principal Component Analysis effectively segregated tumour, WL and NBI tissues appropriately based solely on mRNA tissue profiles. Unsupervised hierarchical clustering defined a primary partition between tumour and non-tumour mRNA profiles; 4 out of 18 (22%) WL but 0 NBI samples clustered with the tumour samples. Gene ontology enrichment portrayed a pattern of increasing cell phenotypic diversity at biopsy sites radiating out from the tumour core; this phenotypic diversity being influenced by both the overall numbers of differentially expressed genes and the breadth of their molecular actions. Upon follow-up, all patients but one were alive, and none had local cancer recurrence.
Conclusion: These results fully support our hypothesis. Greater uptake of narrow band imaging (NBI) diagnostic techniques may improve OSCC surgical success since it invariably defines broader tumour boundaries than conventional white light (WL) examination.