Cancer-associated Abeta mutants fail to reverse tumorigenic phenotype induced by PP2A Abeta suppression, indicating that these mutants function as null alleles.
The PPP2R1B tumor suppressor gene, encoding the beta isoform of the A subunit of serine/threonine-specific protein phosphatase 2A (PP2A-Abeta), located at 11q22-23, is inactivated in patients with cancer.
Although the frequency of alterations is low, the inclusion of both isoforms of subunit A in the genes mutated in human cancer and the addition of breast cancer to the list of neoplasms in which PPP2R1B is altered, strengthen the potential role of PP2A in human tumorogenesis.