Tumour Infiltrating Lymphocytes (TILs) and immune composition in breast cancer patients from Kenya: Spatial distributions and associations with risk factors and tumour characteristics

• Published in: Breast cancer research and treatment Vol. 199; no. 2; pp. 401 - 413
• Main Authors: Sayed, Shahin, Koka, Hela, Abubakar, Mustapha, Gardner, Kevin, Salgado, Roberto, Moloo, Zahir, Caban-Ureña, Ambar Beatriz, Rosen, Daniel, Castro, Patricia, Saleh, Mansoor, Shaikh, Asim Jamal, Shah, Jasmit, Figueroa, Jonine, Makokha, Francis, Ha, Hien Khanh, Wang, Zhong, Magangane, Pumza, Naidoo, Richard, Ngundo, Veronica, Yang, Xiaohong Rose, Govender, Dhirendra
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2023; Springer; Springer Nature B.V
• Subjects: Breast cancer; Breast Neoplasms - pathology; Cancer patients; Cancer research; CD20 antigen; CD3 antigen; CD4 antigen; CD8 antigen; Female; Foxp3 protein; Humans; Immunohistochemistry; Invasiveness; Kenya - epidemiology; Lymphocytes; Lymphocytes, Tumor-Infiltrating; Medical colleges; Medical research; Medicine; Medicine & Public Health; Medicine, Experimental; Menarche; Oncology; Original Laboratory Investigation; Prognosis; Regression analysis; Risk factors; Spatial distribution; Stroma; Tumors; Kenya; Tumour characteristics; Tumour Infiltrating Lymphocytes (TIL); TIL distribution; Breast cancer; Spatial distribution; Immune composition
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-023-06921-3

Background The immune landscape of breast cancer (BC) in patients from Sub Saharan Africa is understudied. Our aims were to describe the distribution of Tumour Infiltrating Lymphocytes (TILs) within the intratumoural stroma (sTILs) and the leading/invasive edge stroma (LE-TILs), and to evaluate TILs across BC subtypes with established risk factors and clinical characteristics in Kenyan women. Methods Visual quantification of sTILs and LE-TILs were performed on Haematoxylin and eosin -stained pathologically confirmed BC cases based on the International TIL working group guidelines. Tissue Microarrays were constructed and stained with immunohistochemistry (IHC) for CD3, CD4, CD8, CD68, CD20, and FOXP3. Linear and logistic regression models were used to assess associations between risk factors and tumour features with IHC markers and total TILs, after adjusting for other covariates. Results A total of 226 invasive BC cases were included. Overall, LE-TIL (mean = 27.9, SD = 24.5) proportions were significantly higher than sTIL (mean = 13.5, SD = 15.8). Both sTILs and LE- TILs were predominantly composed of CD3, CD8, and CD68. We found higher TILs to be associated with high KI67/high grade and aggressive tumour subtypes, although these associations varied by TIL locations. Older age at menarche (≥ 15 vs. < 15 years) was associated with higher CD3 (OR: 2.06, 95%CI:1.26–3.37), but only for the intra-tumour stroma. Conclusion The TIL enrichment in more aggressive BCs is similar to previously published data in other populations. The distinct associations of sTIL/LE-TIL measures with most examined factors highlight the importance of spatial TIL evaluations in future studies.