APBs play a crucial role in the maintenance of telomeres in ALT-positive cancer cells. They serve as a platform for telomere elongation and repair by facilitating the assembly of various proteins involved in homologous recombination. These include RAD51, RPA, and PCNA, among others. The presence of APBs allows cancer cells to maintain their telomeres and thereby continue dividing indefinitely, a key feature of cancer cell immortality.
