KLF9 and pachyonychia congenita: The transcription of MMP28 was suppressed by Krüppel-like factor 9, which therefore inhibited the metastasis and invasion of gastric cancer cells.[22] In hepatocellular carcinoma, upregulation of MMP28 was associated with unfavorable prognosis and Notch3 signaling was indispensable when MMP28 exerted its function.[21] MMP28 was, however, rarely studied in PC.