Increased human buccal cell autofluorescence is a candidate biomarker of tobacco smoking

Human buccal cells display diverse changes that are associated with smoked and smokeless tobacco, and clinicopathologic studies have correlated human buccal cell changes with oral cancer. Reported herein are the results of studies that were undertaken to identify a high-throughput technology that would advance efforts to use human buccal cells. We report that (a) a relatively large (mean +/- SD, 2.1 +/- 1.4 x 10(5) cells) population of human buccal cells can be collected in a noninvasive manner with a toothbrush and purified (>98% human buccal cells; n = 138 samples of the oral mucosa; n = 69 donors); (b) despite their large size (diameter, approximately 65 microm), the human buccal cells were analyzed successfully with a single laser cytometer (FACScan) and an advanced multispectral cytometer (FACSAria) having three lasers (excitation = 488, 633, and 407 nm wavelengths) and nine distinct emission channels; (c) cytometry revealed that the buccal cells expressed a high level of autofluorescence that was displayed over a broad spectrum (450-780 nm wavelength); (d) autofluorescence of human buccal cells collected from the left and right cheek was consistent, illustrating the reproducibility of the sample collection and assay procedure; (e) human buccal cell autofluorescence differed significantly among 69 adult subjects; and (f) a statistical difference (P = 0.018) between current, former, and never smokers. Summarily, this report is thought to be the first to show the application of flow cytometry for assaying human buccal cells and identifies buccal cell autofluorescence as a candidate biomarker of tobacco smoking.