Overall, there was a net gain in mutation in metastatic disease, to 53%; nonetheless, there were instances where metastases were wild type in patients with PIK3CA mutant primary tumors.
On the other hand, PIK3CA gene amplification was found in 21.6% of cases and was strongly associated with distant metastasis (P = 0.002), lymph node involvement (P = 0.032), and advanced tumor stage (P < 0.001).
Intriguingly, these findings imply that PIK3CA mutations are positively selected for during ILBC progression to local recurrence but not distant metastasis, which may have clinical implications for PI3K inhibitor-based therapy.
PIK3CA exon9 mutations associate with reduced survival, and are highly concordant between matching primary tumors and metastases in endometrial cancer.
PIK3CA mutation was independently associated with worse metastasis-free survival (MFS) in IBC since the median MFS for the PIK3CA mutant type was 26.0 months and for the PIK3CA wild type was 101.1 months (p = 0.002).
The primary rectal cancer and the matched metastases (hepatic, pulmonary and lymph nodal) demonstrated no KRAS, NRAS, BRAF and PIK3CA mutations, a microsatellite stable phenotype, and no tumor protein p53 alterations or recurrent copy number alterations on chromosome 8.
First, PIK3CA mutations may interfere with the metastasis process or may induce senescence, which results in a better outcome for patients with mutated tumors.
Metastasis specific mutations are enriched in PI3K-Akt signaling, cell adhesion, ECM and hepatic stellate activation genes, suggesting genetic programs for site-specific colonization.
The combinatorial treatment of PLX4032 and PHA665752, a c-Met inhibitor reversed EMT.Similar results were confirmed in vivo. c-Met-mediated reactivation of the PI3K/AKT pathway contributes to the drug resistance to PLX4032 in BRAF (V600E) mutant anaplastic thyroid cancer cells and further promotes tumor cell migration and invasion by upregulated EMT mechanism.
PIK3CA hotspot mutations are present at a relatively high frequency in CTCs and their presence is associated with worse survival in patients with breast cancer with metastasis.
In addition, the oncogenic PIK3CA(H1047R) mutation was detected in a subpopulation of PV1, but this mutation did not seem to play a major role in vemurafenib resistance in this metastasis.
We next evaluated the impact of MLN0128 on tumor growth, angiogenesis and metastasis using mammary fat pad xenograft models of a non-VEGF (ML20) and a VEGF-driven (MV165) MCF-7 sublines harboring PIK3CA mutations.
PIK3CA mutations occurred more frequently in KRAS-mutated samples (7/18, 38.9%; p = 0.06) than in KRAS wild type (17/90, 18.9%) and showed a very high frequency in metastatic tumors (4/9, 44.4%; p = 0.1) and in samples displaying serous differentiation-serous and mixed endometrioid/serous tumors (6/12, 50.0%; p = 0.021)-where KRAS mutations were rare (11.1% and 16.7%, respectively) and did not exist independently of a PIK3CA mutation.
Although tumors with PIK3CA mutation had a late recurrence pattern, these mutations were common in metastatic disease and were most often associated with persistent ER expression.
Among patients with EGFR mutation and distant metastasis, median PFS was decreased in those with co-mutations (6.3 months [95% CI 3.25-9.35] vs 22.0 months[95% CI 12.10-31.90]; HR 0.12 [95% CI 0.00-5.87]; p = 0.007) and frequency of PIK3CA (0% [0/12] vs 41.7% [5/12], p = 0.037) and PI3K/AKT/mTOR pathway genes (0% [0/12] vs 50% [6/12], p = 0.014) was lower.
It also has been known to lower the phosphorylation of NF-κB and IKKα/β and reduces the metastasis as well as also lowered the ERK1/2 and PI3K activities.