Tat-SP4 also exerted a potent anti-proliferative effect in several cancer cell lines, including triple-negative breast cancer (TNBC) [15], pancreatic ductal adenocarcinoma (PDAC) [16], hepatocellular carcinoma (HCC) [17], and non-small-cell lung cancer (NSCLC) [18]. This evidence concerns the gene SP4 and cancer.