Distribution of molecular breast cancer subtypes among Algerian women and correlation with clinical and tumor characteristics: a population-based study.
BACKGROUND
Breast cancer is currently the leading cause of cancer morbidity and mortality among Algerian women. Molecular classification of breast cancer is an important factor for prognosis and clinical outcome. There are limited data regarding molecular breast cancer subtypes among Algerian women. The objective of the present study was to analyze the proportion and distribution of molecular subtypes and to determine their associations with some clinical and tumor characteristics: age at diagnosis, menopausal status, histological type and histological grade.


METHODS
The study population included 3014 female breast cancers. We analyzed breast cancers from cancer registries of academic medical oncology service of public hospital of Rouiba, anticancer center of Blida, and anticancer center of Batna. Breast cancers were diagnosed between 2008 and 2013. Molecular subtype classification was done based on immunohistochemical surrogates for ER (Estrogen receptor), PR (Progesterone receptor) and HER2 (human epidermal growth factor receptor-2) status obtained from medical records for 3014 breast cancer patients. Breast cancer subtypes definitions were as follow: Luminal A (ER+ and/or PR+, HER2-), Luminal B (ER+ and/or PR+, HER2+), TNBC (ER-, PR - , HER2-), HER2+ (ER-, PR-, HER2+). Molecular subtypes were correlated with the clinicopathological characteristics of the tumors.


RESULTS
The mean age at diagnosis cancer was 48.5 years. Proportions of the luminal A, TNBC, luminal B and HER2+ breast cancer subtypes were 50.59%, 20.80%, 19.67% and 8.92%, respectively. We noted a significant difference in the distribution of age at diagnosis among the four cancer subtypes (P= 0.004). Luminal A, Luminal B, TNBC and HER2+ subtypes were significantly different by premenopausal and postmenopausal status (P= 0.01). Invasive Ductal Carcinoma was the most common histological type in all breast cancer subtypes. Tumors with histological grade 2 and 3 were more common in patients for the four breast cancer subtypes.


CONCLUSIONS
For the first time, we report the distribution of molecular breast cancer subtypes and their associations with some clinicopathological characteristics in a large cohort of Algerian women. In our current study, the median age of diagnosis for all breast cancer subtypes was younger than the average age in Europe and America. Luminal A was the most common sub- type in our patients followed by TNBC. The proportion of luminal A subtype was lesser than reported in white women with breast cancer in Europe and America. The proportion of TNBC subtype in Algerian women was higher compared with Caucasian women of European ancestry. This study will contribute in developing optimal clinical trial protocols and personalized management strategies for Algerian breast cancer patients.
Unit of Genetics, Laboratory of Molecular and Cellular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria.
Farid
F
Cherbal
Unit of Genetics, Laboratory of Molecular and Cellular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria.
Hadjer
H
Gaceb
Unit of Genetics, Laboratory of Molecular and Cellular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria.
Chiraz
C
Mehemmai
Unit of Genetics, Laboratory of Molecular and Cellular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria.
Insaf
I
Saiah
Unit of Genetics, Laboratory of Molecular and Cellular Biology, Faculty of Biological Sciences, USTHB, Algiers, Algeria.
Rabah
R
Bakour
Laboratory of Dynamics and Biodiversity, Faculty of Biological Sciences, USTHB, Algiers, Algeria.
Abdelhalim Ould
AO
Rouis
Radiation Therapy Services, Anticancer Center of Blida, Blida, Algeria.
Kada
K
Boualga
Medical Oncology Services, Anti Cancer Center, Batna, Algeria.
Wassila
W
Benbrahim
Public Hospital Academic Medical Oncology Services, School of Medicine, University of Algiers, Rouiba, Algeria.
Hassen
H
Mahfouf
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000462:Algeria; D044383:Black People; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000473:pathology; D018275:Carcinoma, Lobular / Q000378:metabolism* / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012189:Retrospective Studies; D064726:Triple Negative Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult
D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
Algerian women; breast cancer subtypes; receptor status; triple-negative