Recently, some hydrogel drug delivery systems have been approved for clinical treatment.[21b] A typical example is VANTAS hydrogel implants, which can continuously deliver histrelin for prostate cancer therapy.[31] In addition, we confirmed that SIK2 is overexpressed in the ovarian cancer cells from human patient tumor tissues (Figure S27, Supporting Information). The gene discussed is SIK2; the disease is prostate carcinoma.