CASP3 and obstructive sleep apnea syndrome: The aims of the present study were to evaluate the immunohistochemical pattern and levels of expression of survivin, β-catenin, caspase 3 (inactive [procaspase 3] and active forms), and p53 in canine OSA samples, to reveal specific relations among them and with histological tumour grade, disease free interval (DFI) and overall survival (OS).