These changes include up-regulation of the anti-apoptotic gene BIRC-3, overexpression of the BIRC-3 protein, and reduced expression of the pro-apoptotic gene, MTCH2 in thymic squamous cell carcinomas, and reduced expression of the pro-apoptotic gene, PMAIP1/NOXA in WHO subtype B3 thymomas. This evidence concerns the gene PMAIP1 and thymus squamous cell carcinoma.