Pseudoaneuploid Subpopulations Detected in Normal Upper Aerodigestive Tract Mucosa Consistent with Physiological Apoptosis in Normally Differentiating Squamous Mucosa

Abstract

OBJECTIVES: While evaluating the validity of using normal human mucosal cells from the upper aerodigestive tract as diploid standards for DNA content studies of squamous cell cancer of head and neck by flow cytometry, pseudoaneuploidy was frequently detected. The purpose of this study was to further evaluate these DNA content abnormalities encountered in normal human mucosal cells and correlate them to physiological apoptosis. STUDY DESIGN: Thirty-two specimens of upper areodigestive tract mucosa from 18 surgical resections, 11 fresh autopsies, and 3 buccal scrapings were examined for DNA content by flow cytometry. RESULTS: Pseudoaneuploidy, which ranged from sub-G0/G1 peaks to hyperdiploid peaks with increased 90° light scattering properties was found in 60% of these specimens. Fluorescent microscopic examination of the sorted DNA pseudoaneuploid cells demonstrated cells undergoing apoptosis. CONCLUSION: This unexpected pseudoaneuploidy in normal mucosal cells was a result of physiological apoptosis, a normal component of squamous differentiation. EBM rating: B-2.