PTEN and neoplasm: MSI results in changes in the length of microsatellites—short repetitive DNA sequences—and contributes to genomic instability, which drives tumorigenesis by enabling mutations in key oncogenes and tumor-suppressor genes such as TGF-βR2, BAX, and PTEN. MSI-related mutations in TGF-βR2 impair cell proliferation regulation, while alterations in BAX hinder apoptosis, fostering tumor growth (16, 17).