MMP7 and neoplasm: It is intriguing that the expression level of MMP7 in the tumor tissues was found to be considerably lower compared to the control tissues in breast invasive carcinoma (BRCA), two pathological types of kidney malignant diseases, namely kidney chromophobe (KICH) and kidney renal clear cell carcinoma (KIRC) with P < 0.001, and liver hepatocellular carcinoma (LIHC) with P < 0.05.