Molecular classification of breast cancer: A retrospective cohort study

Abstract

ObjectivesThe study was aimed to determine the distribution of various breast cancer molecular subtypes in Saudi Arabia. Further, association between these subtypes and different epidemiological features was assessed.MethodsA retrospective study was conducted between January 2012 and December 2018, at the King Abdul Aziz University Hospital. A total of 740 cases of breast cancer, using immunohistochemistry, were classified into 4 major molecular subtypes: luminal A, luminal B, HER2-positive, and triple negative. Chi-squared test was performed to evaluate the relationship between these subtypes and clinico-pathological features.ResultsLuminal A (58.5%) subtype was the most prevalent, followed by triple negative (16%), luminal B (14%), and HER2-positive (11.5%). The average age of the patient at the time of diagnosis was found to be 49 years with an average tumor size of 3.2 cm. Out of all cases, 85% of cases were ductal, while 11.4% were lobular. 66.6% showed axillary lymph node metastases. While, 77% of lobular carcinomas were found almost exclusively in the luminal A and triple negative tumor subtype, 69.5% had modified radical mastectomy.ConclusionsLuminal A tumor was the most prevalent subtype, while HER2-positive was the least prevalent. Luminal A tumors were mostly associated with lobular carcinomas. HER2-positive and triple negative tumors showed higher histological grade and larger tumor size at the time of diagnosis. These tumors were commonly found in women below the age of 50 years. Carcinoma-in-situ was less prevalent in HER2-positive tumors. Furthermore, a strong association was observed between axillary lymph node status and molecular subtypes.

Breast cancer in togolese women: immunohistochemistry subtypes

“…Our result is similar to that reported by Effi in Ivory Coast [ 23 ]. However, our finding is lower than those reported in western countries [ 5 ] and Asia [ 29 , 30 ]. The proportion of patients expressing ER (54.7%) is superior to those of PR positive (41%).…”

“…The proportion of patients expressing ER (54.7%) is superior to those of PR positive (41%). The same observation was reported by different authors [ 12 , 23 , 29 , 31 ].…”

“…Luminal A subtype which is a less aggressive type of breast cancer was found in 30.8% of our patients. This rate was lesser than that reported in Saudi Arabia [ 29 ], India [17], and Western countries [ 5 ]. As expected, the Luminal A subtype was associated with favorable clinic and biological characteristics.…”

miRNA Expression Profiles in Luminal A Breast Cancer—Implications in Biology, Prognosis, and Prediction of Response to Hormonal Treatment

“…Aberrant expression of miRNAs is directly associated with numerous malignancies, including BC. Indeed, an altered expression profile of miRNAs can distinguish not only between cancer and healthy samples, but they can classify specific molecular subtypes of BC including HER2, Luminal A (LumA), Luminal B (LumB), and TNBC [ 6 , 17 ]. Early identification and classification of BC subtypes using miRNA expression profiles characterizea promising approach in the field of personalized medicine [ 15 ].…”

Analysis of Spatial Distribution and Prognostic Value of Different Pan Cytokeratin Immunostaining Intensities in Breast Tumor Tissue Sections

“…The molecular prognostic indicators include steroid receptor status, HER2 amplification [ 5 ], and gene signatures such as MammaPrint and Oncotype DX [ 6 , 7 ]. Intrinsic or molecular classification of breast cancer into luminal A, luminal B, basal, normal-like, triple-negative/basal-like, and HER2-enriched also presents prognostic value [ 8 ]. However, the current prognosis of metastasis risk is still not sufficiently reliable.…”