EGFR, BRCA1, BRCA2 and TP53 genetic profile in Moroccan triple negative breast cancer cases.

Abstract

Triple negative breast cancer account for 10% to 20% of all newly diagnosed breast cancer cases, this subtype is well known for its lack of estrogen, progesterone and HER2 expression unlike the other subtypes of breast cancer that usually express at least one of the three. The absence of a specific biomarker for TNBC has made his treatment very challenging and his death rates very high compared to the other subtypes. Therefore, in morocco, many studies have been conducted in the hope of finding a specific biomarker for TNBC, but none of these studies has analyzed the EGFR protein expression and its gene molecular profile and correlated the EGFR analyses results with the genetic profile of other genes. In this study, we analyzed EGFR protein expression and the molecular profile of EGFR, BRCA1, BRCA2 and TP53 genes in 47 TNBC patients. We conducted a retrospective study of 47 Moroccan patients diagnosed with triple negative breast cancer between early 2013 and 2016. In this study, we have analyzed the EGFR. Protein expression, for all the 47 TNBC patients using pharmDx Kit. Then we used the Ion Personal Genome Machine (PGM) and Ion Ampliseq BRCA1/2 panel and hotspot Cancer panel to analyze the molecular profile of BRCA1/2 genes and the hotspot regions of TP53 and EGFR genes. The statistical analysis was performed using IBM SPSS Statistics ver. From the 47 analyzed patients using EGFR pharmDx Kit only 16 (34%) had EGFR overexpression while 31 (66%), patients were normal, moreover, From the 47 TNBC patients, only 39 underwent Mutational analysis of EGFR, BRCA1/2, and TP53 genes. One patient harbored a BRCA1 mutation c.798_799delTT (p.Ser267Lys). While for TP53 gene, 16 patients out of 39 (41%) presented hotspot mutations, seven of them harbored c.743G>A (p.Arg248Gln) mutation, six patients harbored exon 6 mutations from which five harbored the mutation c.659A>G (p.Tyr220Cys) and one the mutation c.817C>T (p.Arg273Cys), and finally, three patients harbored the mutation c.524G>A (p.Arg175His). Regarding BRCA2 and EGFR sequencing results, no mutations or other genetic alterations were detected in 39 patients that were successfully sequenced. Statistical analysis revealed the absence of any correlations.