Single nucleotide polymorphisms (SNPs) in human genes are very significant genetic changes and PCR (polymerase chain reaction) or NGS (next-generation sequencing) are extensively employed in SNP analysis. Thanks to the studies on the progress of new technologies, interest in the isothermal nucleic acid amplification approach has increased. As one of these methods, recombinase polymerase amplification (RPA) represents an attractive option for point-of-care nucleic acid quantification. The target SNPs selected within the scope of the study are mutations identified in the PIK3CA gene region (E542K, E545K), and DNA samples which were evaluated about PIK3CA mutations were isolated from the cancer cells MCF7, BT474, and also SKBr3. The optimization studies for the RPA reaction conditions were carried out for parameters such as assay time, temperature, primer, and also magnesium acetate concentration. According to the results of the reaction optimization studies, in which the RPA products can be obtained in the most efficient way, the assay time was determined as 20 min; the temperature as 40°C; the primer concentration as 10 µM and the MgOAc concentration as 140 mM.