Notably, MMP-9 expression significantly affected the prognosis in five cancer types (Figures 4(a)–4(e)), including ACC (P = 0.003), KIRC (P = 0.002), DLBC (P = 0.010), UCEC (P = 0.018), and SKCM (P = 0.029). Here, MMP9 is linked to adrenal cortex carcinoma.