PIK3CA and colorectal carcinoma: This optimized DNA extraction protocol allowed the recovery of a sufficient DNA amount from fixed rare cells for genomic analyses and was successfully used in a study to detect KRAS, BRAF and PIK3CA mutations in CRC CTCs using Sanger sequencing.8 The ZR Genomic DNATM Tissue MicroPrep kit showed equivalent performance for fixed cells, and could therefore be potentially used as a substitute for the Qiagen QIAamp Micro kit, but no further optimization has been performed in the presented study.