Except for MMP24OS, the transcription level of other MMP family genes, including MMP1, MMP2, MMP3, MMP7, MMP8, MMP9, MMP10, MMP11, MMP12, MMP13, MMP14, MMP15, MMP16, MMP17, MMP19, MMP20, MMP21, MMP23B, MMP24, MMP25, MMP26, MMP27, and MMP28, in the tumor tissues was significantly higher than those in normal tissues. The gene discussed is MMP21; the disease is neoplasm.