Quantification of LC3, p62, and TDP-43 positive fibers in the PM-COX group. The percentage of LC3- (a) and p62-positive fibers (b) was significantly lower in the PM-COX group than in the IBM group, but similar to the PM group. With TDP-43 (c), there was no statistically significant difference between the PM-COX group and either the PM or IBM group. Each subject is represented with a symbol; the open symbols indicate subjects with known IBM clinical presentation. The unbroken lines designate group medians, while the dashed lines mark 100% sensitivity and 100% specificity cutoffs for each marker (derived from the ROC analysis shown in Figure 2). **, p < 0.01.