Cell-based Biosensor for Analysis of Oral Cancer Biomarkers

Oral cancer is the sixth most common cancer worldwide and has been marked by high morbidity and poor survival rates that have changed little over the past few decades. Beyond prevention, early detection is the most crucial determinant for successful treatment and survival of oral cancer. Analysis of molecular biomarkers in brush biopsy specimens offers new opportunities for early detection of high-risk cancerous and pre-cancerous lesions. For widespread use, such tests should be rapid, highly sensitive, and cost effective.

Objective: The goal of this research program was to develop a cell-based sensor to detect oral cancer biomarkers, such as the epidermal growth factor receptor (EGFR) whose over-expression is associated with early oral tumorigenesis and aggressive cancer phenotypes.

Methods: The microfluidic lab-on-a-chip (LOC) device utilizes an embedded track-etched membrane, which functions as a micro-sieve, to capture and enrich cells from brush biopsy suspensions. Once captured, “on-membrane” immunofluorescent assays reveal the degree of biomarker expression via automated microscopy and fluorescent image analysis.

Results: Using the LOC sensor system, with integrated capture and staining technique, EGFR assays were completed in less than 10 minutes with staining intensity, homogeneity, and cellular localization patterns comparable to conventional labelling methods. Further examination of EGFR expression in the three oral cancer cell lines revealed a significant increase (p<0.05) above control cells with EGFR expression similar to normal squamous epithelium. Results obtained in the microfluidic sensor system correlated well with flow cytometry (r2 = 0.98), the “gold standard” in quantitative protein expression analysis.

Conclusions: Taken together, these results support the LOC sensor system as a suitable platform for rapid detection of oral cancer biomarkers and characterization of EGFR over-expression in oral malignancies. Application of this technique may be clinically useful in cancer diagnostics for early detection, prognostic evaluation, and therapeutic selection.

NIH/NIDCR grant #U01DE017793.