Bagaev et al. have identified four tumor microenvironment (TME) subtypes that are conserved across diverse cancers and correlated with immunotherapy response in melanoma, bladder, and gastric cancers. They provided a visual tool revealing the TME subtypes integrated with targetable genomic alterations, which provided a planetary view of each tumor that can aid in oncology clinical decision making. We aim to use this tool to prospectively analyse the biopsy specimens of osteosarcomas to identify their TME subtypes so as to deliver appropriate treatment strategy if these osteosarcomas experience disease progression afterwards. We will compare the past sequencing date stored in PKUPH bank so as to compare the event-free survival(EFS) of these patients to check the Superiority of this method later.

Inclusion Criteria:

• (i) patients who have been suspected for osteosarcoma with enough clinical or radiographic information;
• (ii) patients who have evaluable lesions to resect or follow;
• (iii) patients who are planned to be operate with enough flesh specimens for this study.

Exclusion Criteria:

• (i) clinical information was not complete;
• (ii) lost to follow-up.

Initially treated osteosarcoma