In seven patients, a good concordance of mutations and copy number alterations in ctDNA and tumor samples (NF1, RAD51C, PTEN, BRCA2, STAG2, FANCA, CDKN1B, ERBB2, ERBB4, and MAP 2 K1), and also alterations associated with the clinically available drugs (PI3K/mTOR inhibitor, PARP inhibitor, CDK2/4 inhibitor, CDK4/6 inhibitor, HER2 inhibitor, trastuzumab, ERBB inhibitor, lapatinib, and EGFR inhibitor) were detected. The gene discussed is PIK3CA; the disease is neoplasm.