TP53 and breast cancer: In contrast, Punj et al. showed that azurin is significantly cytotoxic to the MCF-7 cell line (human breast adenocarcinoma cell line) but, interestingly, less cytotoxic against the p53-negative breast cancer cell line (MDA-MB157) or cell lines with non-functional p53, such as MDD2 and MDA-MB-231 [18].