Figure 4From: Single cell mutational analysis of PIK3CA in circulating tumor cells and metastases in breast cancer reveals heterogeneity, discordance, and mutation persistence in cultured disseminated tumor cells from bone marrow PIK3CA G1633A mutation detection in CTCs and tissues over time. One patient, Patient 12, with progressive metastatic breast cancer underwent tissue evaluation and PIK3CA sequencing of a bone (spine) metastasis, lung metastasis, bone marrow biopsy and aspirate (DTCs), and sequential blood draws for one and a half years. Eight out of 10 EpCAM-captured single cells (two cells did not get PCR products for sequencing) in the core needle biopsy of a bone metastases (Bone Bx) from the lumbar spine carried the PIK3CA exon 9 heterozygous mutation G1633A; a lung biopsy (Lung Bx) also showed this mutation; 24 out of 24 EpCAM-captured single cells analyzed from the bone marrow biopsy (BM Bx) carried the heterozygous mutation (EpCAM-captured DTCs retrieved from the bone marrow aspirate). The G1633A mutation was detected only twice in CTCs captured from nine blood samples: one week after bone marrow biopsy, with 10/20 EpCAM-captured cells having the mutation, and six weeks after bone marrow biopsy, with 2/7 EpCAM captured cells having the mutation. Drug treatments are noted (RAD001 = everolimus, an mTOR inhibitor). Note that increasing CTC counts dramatically decreased after treatment with capecitabine and everolimus.Back to article page