Like HAI-1, HAI-2 downregulation and its correlation with disease progression have been observed in many cancers, including malignant brain tumors [88,89], renal cell carcinoma [21,90,91,92], hepatocellular carcinoma [93], gastric adenocarcinoma [94], esophageal squamous cell carcinoma [95], ovarian carcinoma [72], prostate adenocarcinoma [96], and breast carcinoma [39]. The gene discussed is SPINT2; the disease is cancer.