Figure 3: Example of PIK3CA H1047R mutation detection from a trephine biopsy (Case 4). (a) Section from a trephine bone marrow 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 (region indicated by red arrow). (c) High-resolution melting detection of a heterozygous H1047R 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 arrow indicates the presence of a heterozygous mutation changing the codon CAT to CGT (the reverse sequence is shown).