ABSTRACT: We report the results of a molecular study in thirty-seven cases of gliomatosis cerebri, correlating these results with prognosis. The well-known prognostic factors of gliomas, i.e., age, KPS, histology (Grade 2 vs. 3), or contrast enhancement, was predictive of response or outcome only in a percentage of patients but not in all patients. We identified an 8 miRNA signature able to predict patient prognosis with microarray gene expression profiling. The 8 gene features were used to built a prediction method able to distinguish patients with good prognosis (more likely to be responsive to therapy) from patients with a poor prognosis (less likely to be responsive to therapy). Keywords: miRNA expression profile Fifty-nine patients, between 12- and 73-years-old, with clinical signs of increased intracranial pressure were admitted to our institutions between January 2000 to September 2005. Pre-operative neuroradiological studies (CT scan and MRI) showed diffuse infiltrative processes involving more than two different lobes, no identifiable focal mass, and contrast enhancement absent or less than 1 cm in diameter. Written informed consent and tumour DNA were obtained for molecular analysis. Other eligibility criteria included a Karnofsky Performance Scale index (KPS) >50, normal bone marrow function (white blood cell count >3.0X109/l, neutrophil count >1.5X109/l, platelet count >100X109/l, and haemoglobin >10g/dL), normal liver function (aspartate aminotransferase or alanine aminotransferase <2 times the upper limit of laboratory normal, normal bilirubin, and alkaline phosphatase < 2 times the upper limit of normal), and normal renal function (serum creatinine <1.5 mg/dL). The patients received chemotherapy with temozolamide and radiotherapy. The TMZ schedule consisted of 150 to 200 mg/m2 was orally administered once daily on days 1 to 5. Treatment cycles were repeated every 28 days, with a maximum of 24 months. All patients had a monthly neurological and performance status evaluation and a radiological (MRI) evaluation every 2 to 3 months. Responses were evaluated according to previously described criteria (8): a clinical response was defined as an improvement of a neurological deficit or cognitive function evaluated by Mini-Mental Status Examination, an improvement of at least 75% in seizure frequency, or the disappearance of intracranial hypertension. When radiological MRI scans showed a reduction of more than 50% in the hyper intense area it was considered a partial response (PR), and a <50% regression or an objective regression of mass effect, was considered a minor response (MR). Disease was considered as stable when no clinical or radiological changes were seen for at least 6 months, whereas neurological deterioration, a need to increase corticosteroids, or evidence of tumour progression on MRI (an increase in the T2 or the appearance of contrast enhancement) indicated tumour progression.
