IDH-1R132H mutation status in diffuse glioma patients: implications for classification

// Peng-fei Wang 1, * , Ning Liu 1, * , Hong-wang Song 1 , Kun Yao 2 , Tao Jiang 1, 3, 4, 5, ** , Shou-wei Li 1, ** , Chang-Xiang Yan 1, ** 1 Department of Neurosurgery, Sanbo Brain Hospital, Capital Medical University, Beijing, China 2 Department of Pathology, Sanbo Brain Hospital, Capital Medical University, Beijing, China 3 Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China 4 Beijing Neurosurgical Institute, Beijing, China 5 Beijing Institute for Brain Disorders, Beijing, China * Peng-fei Wang and Ning Liu are the co-first authors ** Chang-Xiang Yan, Shou-wei Li and Tao Jiang are the co-corresponding authors Correspondence to: Chang-Xiang Yan, email: yancx65828@sina.com Keywords: gliomas, IDH-1 R132H mutation, prognosis, molecular pathology, Ki-67 Received: December 12, 2015 Accepted: April 11, 2016 Published: April 22, 2016 ABSTRACT WHO 2007 grading of diffuse gliomas in adults is well-established. However, IDH mutations make classification of gliomas according to the WHO 2007 edition controversial. Here, we characterized IDH-1 R132H mut status in a cohort of 670 adult patients with different WHO 2007 grades of diffuse glioma. Patient characteristics, clinical data and prognoses were obtained from medical records. Patients with IDH-1 R132H mut were younger and had better clinical outcomes than those without mutations. Differences in age among patients with astrocytomas of different WHO 2007 grades were eliminated after patients were grouped based on IDH-1 R132H status. IDH-1 R132H mut was present more often in patients with lower Ki-67 and MGMT protein levels and higher mutant p53 levels. Ki-67 was also strongly associated with WHO 2007 grade independently of IDH-1 R132H mut status. Moreover, patients with Ki-67<30 survived longer than those with Ki-67≥30, regardless of IDH-1 R132H mut status. Patients in the IDH-1 R132H mut group with lower MGMT protein levels also had better clinical outcomes than those in other groups. Our results indicate that to better treat gliomas, IDH mutation status should be included when determining WHO 2007 grade in glioma patients.