Abstract 887: Clinicopathological and genetic features of breast cancer in Algerian population: A multicenter study
Authors: Cherbal Farid , Saada Leticia Ledmila , Nehar Massila , Yatta Kamelia , Zerrouki Lydia Souha , Abdou Wafa , Mehemmai Chiraz , Gaceb Hadjer , Benbrahim Wassila , Mahfouf Hassen , Boualga Kada 
Published: July 2021

Abstract
Background: Breast cancer is the most commonly diagnosed cancer and the leading cause of morbidity and mortality among Algerian women.The objective of this retrospective cohort study was to analyze some clinicopathological and molecular characteristics of breast cancer diagnosed between 2011 and 2019. Here we also report the experience of our research laboratory for the screening of BRCA1 and BRCA2 genes in hereditary breast and ovarian cancer (HBOC) patients.
Materials and Methods: The population study included 7655 consecutive breast cancer patients. Data were collected from cancer registries of three medical oncology services and two anti-cancer centers located in north central region and eastern region of Algeria, respectively. Breast cancers were diagnosed between 2011 and 2019. Patient and tumor information included: age at diagnosis, menopausal status, receptor status, Ki-67 score, histological type,TNM stage and histological grade. Recurrent germline mutations on BRCA1 and BRCA2 genes previously found in Algerian patients were screened using PCR-Sanger sequencing in 230 HBOC patients. In addition, 18 HBOC patients were analyzed by NGS using a cancer panel of 30 hereditary cancer genes or BRCA1/2 genetic test.
Results: The median age at diagnosis of the patients was 49.52 years. Data for age at diagnosis were available for 7389 patients. 55.29% patients were diagnosed under the age of 50 years and 55.83% had a premenopausal status. Data for receptor status were available for a total of 5599 patients. Of these, 55.75% patients were luminal A, 19.79% were TNBC, 17.39% were luminal B and 7.05% were HER2+. Data for Ki-67 score were available for 3357 cases. We noticed that 62.73% patients had a Ki-67 score ≥ 20% and 37.27% had a score &lt;20%. Data for histological tumor type were available for 6145 cases. 84.28% patients had invasive ductal carcinoma followed by 8.84% with invasive lobular carcinoma. Data for TNM stage were available for 3524 cases. We identified 59.3% patients with stage III, 22.3% with stage II and 9.5% with stage IV. Data for histological grade were available for 6693 patients. We found 67.45% patients with grade II and 25.51% with grade III, respectively. 10 distinct BRCA1 germline mutations have been detected in 18 families and 5 distinct BRCA2 germline mutations have been identified in 5 families. The BRCA1 recurrent mutation c.83_84delTG has been detected in 5 unrelated families.The BRCA1 recurrent mutation c.2125_2126insA has been identified in 3 unrelated families. In addition, the BRCA1 c.181T&gt;G has been found in two unrelated families. Interestingly, our results also showed differences in the distribution of the mutation spectrum of BRCA1 and BRCA2 genes between the eastern region and the north central region of Algeria.
Conclusion: Our current study will contribute in developing optimal clinical trial protocols and personalized management strategies for breast cancer patients.
Citation Format: Farid Cherbal, Leticia Ledmila Saada, Massila Nehar, Kamelia Yatta, Lydia Souha Zerrouki, Wafa Abdou, Chiraz Mehemmai, Hadjer Gaceb, Wassila Benbrahim, Hassen Mahfouf, Kada Boualga. Clinicopathological and genetic features of breast cancer in Algerian population: A multicenter study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 887.