RYR1 and neoplasm: Similarly, low tumor CcO activity was not associated with age (hazard ratio, 0.57; P = 0.52), gender (hazard ratio, 0.56; P = 0.31), the treatment administered (hazard ratio, 0.84; P = 0.98), or MGMT promoter methylation status (hazard ratio, 0.9; P = 0.83).