Interestingly, we found that low level of SIRT5 was also associated with tumors that are not primary chordoma (6 out of 13), suggesting that other primary tumors may have a low level of SIRT5 or that other primary tumors may have a high level of SIRT5 while the SIRT5 level was decreased when progressing and metastasizing. The gene discussed is SIRT5; the disease is chordoma.