Search for pathogenic changes in the PIK3CA gene in women with HR+/HER- subtype breast cancer from the Republic of Bashkortostan

Abstract

A study was carried out to identify the spectrum and frequency of pathogenic changes in the PIK3CA gene in the tumor tissue preparations of 60 women with hormone-dependent HER2-negative breast cancer from the Republic of Bashkortostan using the allele-specific polymerase chain reaction. As a result 32 pathogenic variants in the PIK3CA gene were identified: 18 mutations in exon 9 and 14 mutations in exon 20. The most frequent mutation was H1047R (p.His1047Arg(c.3140A>G)), which accounted for 21.6%. The second most frequent mutation was E545K (p.Glu545Lys (c.1633G>A)), which was 20%. E542K (p.Glu542Lys(c.1624G>A)), E545A (p.Glu545Ala(c.1634A>C)) mutations in exon 9 and H1047L (p.His1047Leu(c.3140A>T)) in exon 20 were identified with a frequency of 8.3%, 1.6% and 1.6% respectively. The results show a high frequency of somatic mutations in the PIK3CA gene (50%), indicating the need to identify pathogenic changes for adequate therapy of breast cancer.