Abstract 5284: Triple-negative breast cancer in Algerian population: clinicopathological and molecular study

Abstract

Background:Triple-negative breast cancer (TNBC),defined by the absence of estrogen receptor (ER), progesterone receptor (PR),and human epidermal growth factor receptor 2 (HER2) expression, accounts for 12% to 20% of all breast cancers.Its prevalence differs between races.TNBC shows substantial overlap with basal-type and BRCA1-related breast cancers and it is associated with early recurrence of disease and poor outcome.In the current study, we sought to compare some clinical and tumor characteristics of breast cancer patients with or without TNBC. We also screened for the prevalence of germline BRCA1 mutations in TNBC patients. Materials and Methods: Clinical and tumor characteristics data of 3403 breast cancer patients were collected from cancer registries of anticancer center of Blida, public hospital of Oued Amizour, anticancer center of Batna and public hospital of Rouiba. Breast cancers were diagnosed between 2007 and 2014. All histopathologic and immunohistochemical diagnoses were reviewed by pathologists. Patients were divided in two groups: those with TNBC and those with other breast cancer subtypes. Differences between the two groups with regard to clinicopathologic parameters: age at diagnosis, menopausal status, histological grade and histological type, were examined using Chi-square test. BRCA1 was screened by PCR-direct sequencing in 56 TNBC patients (26 with a family history of breast cancer and 30 sporadic cases) including all exons where a mutation was previously found in Algerian population (exons 2, 3, 5, 11). Results: The median age at diagnosis for TNBC and non-TNBC patients was 46.96 years and 49.01 years, respectively.The overall prevalence of TNBC was 21.65% (737/3403). Our data showed significant differences in the distribution of age at diagnosis (P<0.0005) and tumor histological grade (P<0.0001) between TNBC and non-TNBC patients.Among tumor with histological grade III,TNBC accounted for 50.54% for all TNBC patients and non-TNBC accounted for 25.28% for all non-TNBC patients.Premenopausal women accounted for 60.71% and 58.9% for all TNBC patients and all non-TNBC patients, respectively. Our data analysis revealed no difference in the distribution of histological tumor type between the two groups.Two BRCA1 mutations, c.83_84delTG and c.2125_2126insA have been detected in two young TNBC patients with a family history of breast cancer. Interestingly, the mutation c.2125_2126insA has been detected in 4 relatives of TNBC proband.Conclusions:This largest Algerian population-based study showed that the prevalence of TNBC in Algerian women is similar to that in African-American patients and higher than reported in white women in Europe and America. The high prevalence of TNBC in Algerian women compared to western countries could be linked to environmental factors and genetic background. Further research is needed to determine long term survival rates in the two groups of breast cancer patients. Citation Format: Farid Cherbal, Hadjer Gaceb, Chiraz Mehemmai, Insaf Saiah, Rabah Bakour, Abdelhalim Ould-Rouis, Tarek Touahria, Hassen Mahfouf, Samia Daoudi, Wassila Benbrahim, Kada Boualga. Triple-negative breast cancer in Algerian population: clinicopathological and molecular study. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5284. doi:10.1158/1538-7445.AM2015-5284