Abstract AIMS The aim of the study is to identify machine learning model based on radiological biomarkers that can predict immune status within tumor microenvironment of IDH wildtype glioblastoma. METHOD This is a retrospective multicenter machine learning based study utilizing open access anonymized matched radiogenomic data of TCGA-GBM, CPTAC, Ivy GAP and REMBRANDT datasets. REMBRANDT data acted as hold out dataset. Imaging data consisted of MRI based radiomics features extracted from deep learning based segmented tumors and transcriptomic (RNA seq/microarray) data consisted of immune scores extracted using CIBERSORTx. Outliers were identified and filtered using principal component analysis. Combat and neuroCombat were utilized for data harmonization for each data type respectively. Radiomic feature selection was performed using LASSO technique with cross validation. Support vector machine (SVM) was trained and tested with 80:20 radiomics data split and a median based binary label of immune score (low and high). Validation of the trained model was performed with hold out dataset. Data query and analysis was performed using python and R statistical software. RESULTS One hundred one patients were included in the study with 15 being on the hold out set. Trained SVM model predicted the immune score label with AUC of 0.79 and balanced accuracy of 0.76 (recall 0.75, F1 score 0.75, precision 0.75) in the test data. In the holdout set, the model predicted the immune score with AUC of 0.70 with specificity of 75% in predicting the cold immune cases. The radiomic signature that acted as the label for this model were a group of first order and second order radiomic features. CONCLUSION Radiogenomic SVM model non-invasively predicts immune status in wildtype glioblastoma microenvironment with good accuracy. This model has potential to be utilized in a prospective glioblastoma clinical trial for immunotherapy.
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