A2M and obstructive sleep apnea syndrome: Using MALDI-TOF/TOF MS analysis, eight proteins (GTF2I, MIPOL-1, CFAP298, PGAM1, UB2L6, EDARADD, LRRC72, and A2M) were found to be significantly differentially (p ≤ 0.05) expressed in canine OSA cell lines (both OSCA-8 and OSCA-32) compared to CnOb.