AUTHOR=Chen Sijie , Zhou Wenjing , Tu Jinghui , Li Jian , Wang Bo , Mo Xiaofei , Tian Geng , Lv Kebo , Huang Zhijian TITLE=A Novel XGBoost Method to Infer the Primary Lesion of 20 Solid Tumor Types From Gene Expression Data JOURNAL=Frontiers in Genetics VOLUME=Volume 12 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2021.632761 DOI=10.3389/fgene.2021.632761 ISSN=1664-8021 ABSTRACT=Purpose: Establish a suitable machine learning model to identify its primary lesions for primary metastatic tumors in an integrated learning manner, making it more accurate to improve the diagnostic efficiency of primary lesions. Methods: After deleting the features whose expression level is lower than the threshold, we use two methods to perform feature selection respectively and use XGBoost for classification. After the optimal model is selected through 10-fold cross-validation, it is verified on an independent test set. Results: Selecting features with around 800 genes for training, the -score of 10-cv of training data can reach 96.38%, and the -score of test data can reach 83.3%. Conclusion:These findings suggest that by combining tumor data with machine learning methods, each cancer has its corresponding classification accuracy, which can be used to predict the location of primary metastatic tumors. The machine-learning-based method can be used as an orthogonal diagnostic method to judge the machine learning model processing and clinical actual pathological conditions.