Question

Please explain the importance of EMT in osteosarcoma? Please explain the study of Zhu et al (2020) to describe the molecular events underlying EMT in osteosarcoma?

Answer 1

Osteosarcoma is the most common type of bone cancer in children and young adults. Recent studies have shown a correlation between epithelial–mesenchymal transition (EMT)-related gene expression and immunity in human cancers. Here, we investigated the relationship among EMT, immune activity, stromal activity and tumor purity in osteosarcoma.

Osteosarcoma is the most common type of bone cancer in children and young adults and is responsible for approximately 9% of cancer deaths in children and adolescents aged 10–24 years (Biazzo & De Paolis, 2016; Maximov et al., 2019). Chemotherapy and surgical intervention can increase the 5 year survival rate to 60–70%. However, the 5 year survival rate is below 30% for patients who have metastatic disease at diagnosis or recurrence (Sayles et al., 2019; Shen et al., 2017). Thus, it is important to explore the mechanisms underlying osteosarcoma metastasis to improve patient prognosis.

Tumor metastasis begins with epithelial–mesenchymal transition (EMT), in which epithelial cells acquire a mesenchymal phenotype and become migratory and invasive (Shen et al., 2017; Wang et al., 2018). Loss of the epithelial marker E-cadherin and an increase in the expression of mesenchymal markers are characteristics of EMT. EMT promotes primary epithelial-like tumor cells to acquire invasive mesenchymal phenotypes during metastatic progression. This progression, along with increased motility and invasiveness, triggers the dissemination of metastatic cells from the tumor, which then infiltrate into the tumor vasculature (Lv et al., 2016). Hence, EMT-related genes are potential markers and therapeutic targets for osteosarcoma treatment.