MMP9 and neoplasm: These characteristics include the following: increased cell proliferation, migration, invasion, colony formation, and chemoresistance; higher expression of multidrug-resistance- and cancer-stemness-related genes; elevated levels of molecules linked to tumor progression (Snail, Slug, Twist, Zeb1, Zeb2, Notch1, Notch2, MMP2, MMP9, Sox2, Oct4, Nanog, KLF4, and integrins); and substantial enrichment of prostate CSCs compared to traditional 2D cultures.