Dr. Tadahisa Shono, Dr. Masahiro Mizoguchi and their colleague (Dept. Neurosurgery) confirmed that the prognosis of the patient with malignant glioma is highly depends on the chromosomal abnormality determined by loss of heterozygosity (LOH) analysis. When the tumor cells harbor allelic losses of Chromosome 10 (Chr. 10 LOH), the clinical outcomes of the patients are dismal. Despite the use of surgery, radiation, and conventional chemotherapy, most patients with tumors harbor Chr. 10 LOH died within 2 years. In contrast, when the tumor cells contain paired deletions of Chromosome 1p and 19q (1p, 19q LOH), all patients treated with surgery and chemotherapy survived longer than 3 years without postoperative radiotherapy. Therefore, they select the postoperative adjuvant therapy according to the results of these genetic analyses. When the tumor cells harbor Chr. 10 LOH, the patients are given both radiotherapy and chemotherapy using new anti-tumor agent, temozolomide. On the other hand, when the tumor cells harbor 1p, 19q LOH, the patients are treated with conventional chemotherapy, called PAV (procarbazine, ACNU, vincristine) without radiotherapy.