PIK3CA and pneumonitis: In the CT-09 case, the increase of circulating PIK3CA H1047R clearly predicted the evolving resistance to fulvestrant six months prior to clinical progression; bone scan and CT were performed at the time of clinical symptoms and tumor marker elevation, which showed new bone metastases; the specific everolimus-exemestane therapy caused a dramatic fall in its concentration; nevertheless, due to grade 3 treatment-specific pneumonitis, the patient refused further therapies (Figure 5).