Figure 1: Example of PIK3CA E545 K mutation detection from a CT-guided biopsy sample (Case 2).(a) Section from a CT-guided biopsy sample stained with hematoxylin and eosin. The bar shows a distance of 50 μm. (b) Closeup of the same section showing the presence of breast cancer cells (indicated by red arrows). (c) High-resolution melting detection of a heterozygous E545 K mutation in DNA isolated from the sample (blue line, T47D DNA; red line, MCF7 DNA; green line, sample DNA). (d) Confirmation of mutation by Sanger sequencing. The red arrrow indicates the presence of a heterozygous mutation changing the codon GAG to AAG.