Breast biomarkers profile of invasive lobular carcinoma in a cohort of arab women shows no significant differences from carcinoma of no special type

Abstract

Objectives: Invasive lobular carcinoma (ILC) of the breast is known for its common presentation at an older age, and the frequent expression of favourable profile of estrogen and progesterone receptors (ER & PR) positivity, and human epidermal growth factor receptor 2 (HER2) negativity combined with low proliferation rate as measured by Ki67. This study aimed to test these clinicopathological features of ILC in an Arabic cohort. Methods: All breast biopsies diagnosed as IDC or ILC were retrospectively reviewed over 2 years period (2017-2018) in an academic centre. Variables were compared using Fisher’s exact test for statistical significance. Results: A total of 134 cases were recruited, 12.7% were ILC. The median age was 52 years for both types. Clustering of ILC cases was noticed in luminal A subtype (47.1%), but there was no statistically significant difference in subtyping between the 2 histologic groups. Ki67 was significantly lower in ILC than IDC category. Conclusions: Our study showed that ILC in our cohort lacks the advantage of older age and the common high expression of ER positivity in comparison to IDC. There is, however, significant difference of the value of Ki67 proliferation marker. The prognosis of lobular morphology is questionable in our cohort. Keywords: Biomarkers; breast carcinoma types; immunohistochemistry; invasive lobular carcinoma; Ki67.