A cell in its natural environment spends its time in a quiescent state known as G0.A challenge the cell faces is to determine when the conditions are favorable for it to grow.

• 纤维肉瘤是软组织肉瘤的一种，无论是以放射线治疗或化学药物治疗，都发现癌细胞会对这些治疗方式产生抗性，因此纤维肉瘤的愈后情况不良。