TP53 and breast cancer: They have demonstrated the G2/M arrest in other cell lines, including I7 mouse spindle carcinoma cells via an increase in p53 and decrease in cyclin B [58], MNNG/HOS human osteosarcoma cells due to p21WAF1 upregulation [53], MCF-7/DOX doxorubicin-resistant breast cancer cells through an increase in p53 and p21 proteins [108], and MNNG/HOS osteosarcoma cell lines by the upregulation of p21Waf1 [53].