CD8+ T Lymphocyte Infiltration: A Favourable Prognostic Indicator in Indian Patients with Breast Carcinoma

Abstract

Introduction: Breast cancer is the most commonly diagnosed cancer in women worldwide with over 2.1 million new cases per year. While hereditary and genetic factors as well as many conventional prognostic markers are well established in clinical practice, the role of host immunity in the determining the prognosis is still not clearly understood. Aim: To evaluate the association of Tumour-Infiltrating Lymphocytes (TILs) with known prognostic markers and disease outcome parameters in a cohort of breast carcinoma patients from India. Materials and Methods: Formalin Fixed Paraffin Embedded (FFPE) sections from patients of breast carcinoma who underwent definitive surgery were stained with anti-CD8 antibody by Immunohistochemistry (IHC) and mean number of Intratumoural (iTILs), Stromal (sTILs) and Total (tTILs) TILs ascertained. These were compared with known prognostic markers and survival data using median and inter-quartile range. Wilcoxon-Mann-Whitney test was used. Results: 75 of the 184 cases of breast carcinoma that met the inclusion criteria were included in the study. A statistically significant association was seen with iTIL (p=0.041) and tTIL (p=0.037) for patients with relapse. No association, however, was seen with hormonal receptor status, Her2 neu positivity, the Intrinsic molecular subtypes or other known prognostic markers like the grade, tumour size, nodal metastasis and TNM stage. Conclusion: The present study shows that higher levels of iTIL and tTIL but not sTIL are associated with a lower rate of recurrence and have a better prognosis. TILs appear to be independent markers as none of the known prognostic markers like tumour size, lymph node status are associated with TILs in present cohort.

Keywords

• breast neoplasms
• prognosis
• recurrence
• t-lymphocyte subsets