p62 Is a Potential Biomarker for Risk of Malignant Transformation of Oral Potentially Malignant Disorders (OPMDs)

To determine the intracellular behavior of p62, a marker of selective autophagy, in oral potentially malignant disorders (OPMDs). This retrospective study includes 70 patients who underwent biopsy or surgical resection and were definitively diagnosed with OPMDs. Immunohistochemical staining for p62, XPO1, p53, and ki67 was performed on all samples and positive cell occupancy was calculated. We statistically investigated the correlation between protein expression in OPMDs and the association between malignant transformation, clinicopathological characteristics, and occupancy. ki67 expression was negatively correlated with p62 expression in the nucleus (p < 0.01) and positively correlated with p62 expression in the cytoplasm (p < 0.01). For malignant transformation, the expression of p62 in the nucleus (p = 0.03) was significantly lower in malignant transformation cases, whereas the expression of p62 in the cytoplasm (p = 0.03) and the aggregation expression (p < 0.01) were significantly higher. Our results suggest that the function of p62 is altered by its subcellular localization. In addition, defects in selective autophagy occur in cases of malignant transformation, suggesting that p62 is a potential biomarker of the risk of malignant transformation of OPMDs.