Epidermal growth factor receptor (EGFR) family members are known to have important roles in breast cancer development. Clinical trials of EGFR tyrosine kinase inhibitor (TKI) in unselected breast cancer patients have not yielded promising results. Moreover, the presence of TKI-sensitive EGFR mutations may be rare and has not been clarified in different breast cancer subtypes in Indonesia.
Direct DNA sequencing was used to determine specific EGFR mutations, namely L858R and L861Q informalin fixed paraffin embedded (FFPE) samples collected from 152 consecutive breast cancer patients treated in Dharmanugraha Hospital. The study was approved by Dharmanugraha ethics committee. The archived specimens comprised of luminal A (45%), triple-negative (27%), and HER2-positive subtypes (28%).
EGFR mutation, L858R and L861Q, was found in all subtypes of breast cancers. Overall prevalence of EGFR mutation L858R was 11.84% (18 of 152) and predominantly found in HER-2 positive subtype (13.95%), followed by TNBC subtype (12.20%) and luminal A subtype (10.29%). L861Q mutations were detected more frequently than L858R mutations (19.08% vs 11.84%, respectively). The L861Q mutation was found most frequently in luminal group (23.53%), followed by TNBC group (17.07%) and HER-2 positive group (13.95%).
Tyrosine kinase inhibitor-sensitive EGFR mutations were present in all types of breast cancers. The incidence of EGFR mutation of L861Q was higher than L858R. The mutation of L858R was distributed almost evenly in all type of breast cancers. On the other hand, L861Q was commonly found in luminal group compared with two other groups. Indonesian breast cancer patients harboring TKI-sensitive mutations may be eligible for clinical trials evaluating TKI efficacy.
Clinical trial identification
Legal entity responsible for the study
Institutional Review Board, Stem Cell and Cancer Institute
PT. Kalbe Farma
All authors have declared no conflicts of interest.