PIK3CA and cancer: PTEN further aims to promote DNA repair and assist with chromosome stability.76 Discovered in 199777 on chromosome 10,78 loss of the PTEN protein is more frequently associated with cancer, than PTEN gene mutations which are seen in approximately 13.5% of all human cancers.79 With the loss of the negative regulator for PI3K, the PI3K pathway80 is activated with cellular proliferation and survival resulting.