The frequency and spectrum of PIK3CA mutations in patients with estrogen receptor-positive HER2-negative advanced breast cancer residing in various regions of Russia

• DOI: 10.26442/18151434.2021.1.200744
• Publication Date: 2021-05-19T13:07:55Z
• Authors: Tatiana N. Sokolova; Svetlana N. Aleks...; Grigoriy A. Yanus; Aleksandr V. Sult...; Konstantin V. Men...; Anna N. Lysenko; Ruslan A. Zukov; Alena V. Zyuzyukina; Yulia N. Murunova; Elena I. Rossokha; Sergey Y. Bakharev; Elena A. Basova; Tatiana A. Kasmynina; Irina S. Shumskaya; Yana I. Bakshun; Khedi S. Musaeva; Alfia I. Khasanova; Vadim N. Dmitriev; Marina B. Bolieva; Christina H. Gadz...; Oleg L. Petrenko; Dmitriy A. Maksimov; Vladimir I. Vladi...; Viktor E. Goldberg; Nataliya O. Popova; Marianna V. Kibis...; Zaur M. Khamgokov; Alexey E. Vasilyev; Aglaya G. Iyevleva; Evgeny N. Imyanitov
• Keywords: 03 medical and health sciences; Breast cancer; 0302 clinical medicine; 610; PIK3CA; Mutations; Alpelisib; 3. Good health

Relevance. PIK3CA belongs to the top three most frequently mutated genes in breast cancer (BC), especially estrogen receptor (ER) positive, HER2 negative BC subtype. With an approval of selective PI3K-alpha inhibitor, alpelisib, this alteration has become actionable ER+HER2- tumors. The frequency and spectrum alterations various cohorts is affected by a number factors, including distribution expression subtypes, histological types, patient age, even ethnicity.
 Aim. Aim current study was characterize Russian patients.
 Materials methods. analysis exon 7, 9 20 mutations performed cohort patients combination high-resolution melting analysis, allele-specific PCR, digital droplet PCR.
 Results. lesions were identified 62/206 (30%) patients. Noteworthy, 59/62 (95%) variants represented common p.E542K, p.E545K, p.H1047R substitutions. clinical morphological characteristics revealed trends towards association with older age more frequent metastatic lung involvement.
 Conclusion. obtained data on somatic aberrations can be helpful when organizing molecular genetic testing using PI3K inhibitors population.