AUTHOR=Wang Shouju , Mao Hui , Cheng Zhen , Teng Zhaogang , Sun Xiaolian TITLE=Editorial: Advances in the Understanding of Tumor Microenvironment: Molecular and Theranostic Imaging JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=9 YEAR=2021 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2021.731119 DOI=10.3389/fbioe.2021.731119 ISSN=2296-4185