A useful protocol for analyses of mutations of the epidermal growth factor receptor gene

Recent studies have reported that mutations of the epidermal growth factor receptor (EGFR) gene are associated with the responsiveness of tyrosine kinase inhibitors (TKIs), which are molecular targets for non-small cell lung cancer (NSCLC). To provide genetic analyses for NSCLC patients, a simple and reliable method using paraffin-embedded materials is needed. The DEXPAT DNA extraction kit was used for DNA extraction from paraffin-embedded materials. DNA was amplified using the nested PCR technique, then analyzed by direct sequencing for EGFR mutations (exons 18 to 21). The phenol/chloroform extraction for DNA was also performed for comparison. When the DEXPAT kit was used, distinct bands were observed in all products after nested PCR assays of paraffin-embedded materials. Distinct sequencing signals were obtained. Results from the sequencing analysis of paraffin-embedded materials and frozen materials were completely concordant. The current study suggests that DNA extraction with the DEXPAT kit followed by nested PCR is a simple and reliable technique for analyzing the EGFR gene status with paraffin-embedded samples.