Replication Limits

Replicative senescence is treated as cancer-suppressive because it limits clonal expansion and mutation opportunities. The replication-limit model assigns every wild-type cell a nonnegative replication capacity. A wild-type cell with positive replication capacity divides into two daughters with one less unit of capacity. Replication limits cap the supply of dividing wild-type cells over time. A wild-type cell with zero replication capacity becomes senescent and stops dividing. With finite replication capacity, the dividing wild-type population eventually disappears even if initial net growth is positive. Most human somatic cells undergo replicative senescence after a finite number of divisions.