Clinical trials optimizing investigator and self‐collection of buccal cells for RNA yield

Abstract

Abstract Objective Buccal cells are an ideal surrogate tissue for studying biologic effects of carcinogens or drugs, however inherent fragility and salivary RNAses limit RNA yield. We conducted healthy volunteer trials to optimize collection conditions. Methods We conducted: (a) a single‐arm crossover study evaluating four test conditions on RNA yield by buccal cytobrush; (b) a single‐arm prospective study evaluating RNA yield by investigator vs self‐collection. Results Antecedent toothbrushing, time of day, and number of cytobrush strokes did not significantly impact RNA yield. RNA yield was doubled by using 2 vs 1 cytobrush per buccal surface (P = .0054). Self‐collection of buccal cells for RNA was feasible; 36 of 50 (72%) samples passed quality control. Conclusion RNA yield was doubled by using two cytobrushes per buccal surface. Healthy volunteers can self‐collect sufficient buccal RNA for gene expression studies. Techniques from these pragmatic trials could enhance availability of a limited tissue for serial biomarker measurements. Level of Evidence 1b—Prognosis Study (Individual prospective cohort study).

Keywords

• biomarker
• buccal cell
• cytobrush
• evidence‐based medicine
• molecular biology
• oral cavity