Differential immune cell densities in ductal carcinoma In-Situ and invasive breast cancer: Possible role of leukocytes in early stages of carcinogenesis

Delineating the breast cancer immune microenvironment in the era of multiplex immunohistochemistry/immunofluorescence

Breast cancer is the most common malignancy and the leading cause of cancer death in females worldwide. Treatment is challenging, especially for those who are triple-negative. Increasing evidence suggests that diverse immune populations are present in the breast tumour microenvironment, which opens up avenues for personalised drug targets. Historically, our investigations into the immune constitution of breast tumours have been restricted to analyses of one or two markers at a given time. Recent technological advances have allowed simultaneous labelling of more than 35 markers and detailed profiling of tumour-immune infiltrates at the single-cell level, as well as determining the cellular composition and spatial analysis of the entire tumour architecture. In this review, we describe emerging technologies that have contributed to the field of breast cancer diagnosis, and discuss how to interpret the vast data sets obtained in order to effectively translate them for clinically relevant use.

Differential Immune Landscape of Hepatocellular Carcinoma Suggests Potential role of Macrophages in Hepatocarcinogenesis

Objectives

To investigate immune cell densities in tumor microenvironment of hepatocellular carcinoma.

Methods

This cross-sectional study was conducted during 2017-2019 at the Dow University of Health Sciences Karachi. A total of 42 subsequent patients undergoing liver biopsy/resection and diagnosed with hepatocellular carcinoma were included in the study. Moreover, a total of 10 control tissues were also included. In order to investigate immune cells densities in hepatocellular carcinoma, immunohistochemistry was performed using antibodies including α-MPO(neutrophils), α-CD-68(macrophages), α-CD-3(T-cells), α-CD-20(B-cells), α-CD-4(CD4+ T-cells) and α-CD-8(CD8+ T-cells). Quantification of immune cells/mm² was performed as per the College of American Pathologists' guidelines. Data were analyzed using SPSS version 21. A p-value of 0.05 was considered significant at all times.

Results

We report significantly increased infiltration of macrophages (mean macrophages= 306.57/mm², p-value <0.05), moderately significant infiltration of neutrophils (p-value=0.06) and B-cells (p-value=0.07) while no significant infiltration of CD4+T-cells (p- value=0.31), and CD8+T-cells (p-value=0.39) in tumour microenvironment of patients with hepatocellular carcinoma.

Conclusion

We provide evidence for increased macrophage infiltration in liver cancer microenvironment suggesting a potential role of these cells in hepatocarcinogenesis.

Prognostic role of immune infiltrates in breast ductal carcinoma in situ

PURPOSE

Ductal carcinoma in situ (DCIS) of the breast is often regarded as a non-obligate precursor to invasive breast carcinoma but current diagnostic tools are unable to accurately predict the invasive potential of DCIS. Infiltration of immune cells into the tumour and its microenvironment is often an early event at the site of tumourigenesis. These immune infiltrates may be potential predictive and/or prognostic biomarkers for DCIS. This review aims to discuss recent findings pertaining to the potential prognostic significance of immune infiltrates as well as their evaluation in DCIS.

METHODS

A literature search on PubMed was conducted up to 28th January 2019. Search terms used were "DCIS", "ductal carcinoma in situ", "immune", "immunology", "TIL", "TIL assessment", and "tumour-infiltrating lymphocyte". Search filters for "Most Recent" and "English" were applied. Information from published papers related to the research topic were synthesised and summarised for this review.

RESULTS

Studies have revealed that immune infiltrates play a role in the biology and microenvironment of DCIS, as well as treatment response. There is currently no consensus on the evaluation of TILs in DCIS for clinical application.

CONCLUSIONS

This review highlights the recent findings on the potential influence and prognostic value of immunological processes on DCIS progression, as well as the evaluation of TILs in DCIS. Further characterisation of the immune milieu of DCIS is recommended to better understand the immune response in DCIS progression and recurrence.

Immune Escape in Breast Cancer During In Situ to Invasive Carcinoma Transition

To investigate immune escape during breast tumor progression, we analyzed the composition of leukocytes in normal breast tissues, ductal carcinoma in situ (DCIS), and invasive ductal carcinomas (IDC). We found significant tissue and tumor subtype-specific differences in multiple cell types including T cells and neutrophils. Gene expression profiling of CD45+CD3+ T cells demonstrated a decrease in CD8+ signatures in IDCs. Immunofluorescence analysis showed fewer activated GZMB+CD8+ T cells in IDC than in DCIS, including in matched DCIS and recurrent IDC. T-cell receptor clonotype diversity was significantly higher in DCIS than in IDCs. Immune checkpoint protein TIGIT-expressing T cells were more frequent in DCIS, whereas high PD-L1 expression and amplification of CD274 (encoding PD-L1) was only detected in triple-negative IDCs. Coamplification of a 17q12 chemokine cluster with ERBB2 subdivided HER2+ breast tumors into immunologically and clinically distinct subtypes. Our results show coevolution of cancer cells and the immune microenvironment during tumor progression.Significance: The design of effective cancer immunotherapies requires the understanding of mechanisms underlying immune escape during tumor progression. Here we demonstrate a switch to a less active tumor immune environment during the in situ to invasive breast carcinoma transition, and identify immune regulators and genomic alterations that shape tumor evolution. Cancer Discov; 7(10); 1098-115. ©2017 AACR.See related commentary by Speiser and Verdeil, p. 1062This article is highlighted in the In This Issue feature, p. 1047.

Increased Tumour Infiltration of CD4+ and CD8+ T-Lymphocytes in Patients with Triple Negative Breast Cancer Suggests Susceptibility to Immune Therapy

Background:

Patients with triple negative breast cancer (TNBC) have limited therapeutic options, largely because the complex tumour environment is not well-characterized. These patients are potential, but largely un-fathomed, candidates for immunotherapy. It is therefore highly relevant to characterize leukocyte complexity in TNBCs.

Objective:

To investigate leukocyte complexity in tumour environment of patients with TNBCs.

Materials and methods:

A total of 104 consecutive breast cancer patients undergoing mastectomy were recruited in the study after ethical approval. Clinico-pathological parameters were recorded and H and E staining was performed to investigate tumour morphology. Receptor status was investigated using antibodies against ER, PgR and Her-2, and patients were classified as having TNBC or non-TNBC tumours (including Luminal A, Luminal B and Her2 overexpressing tumours). Immune-cell infiltration was investigated using special stains and antibodies: α-CD3 (T-lymphocytes), α-CD20 (B-lymphocytes), α-CD4 (helper T-lymphocytes) and α-CD8 (cytotoxic T-lymphocytes). Immune cell densities were quantified as cell/mm² using the CAP guidelines.

Results:

Of the 104 breast cancer patients investigated, a total of 27 (26%) had TNBC and 77(74%) non-TNBC. Patients with TNBC showed significantly increased tumour infiltration of lymphocytes (T and B-lymphocytes) compared to the patients with non-TNBC, while myelocytic infiltration was not significantly different in the two groups. Within the TNBC group, infiltration of T-lymphocytes (equal densities of CD4+ and CD8+ T-lymphocytes) was significantly higher compared to B-lymphocytes.

Conclusion:

Patients with TNBC show increased lymphocytic infiltration (more T-lymphocytes compared to B-lymphocytes). This suggests higher immunogenicity of TNBCs and may indicate a higher responsiveness of these cancers to immunotherapy.

Prognostic significance of tumour infiltrating B lymphocytes in breast ductal carcinoma in situ

AIMS

Tumour-infiltrating lymphocytes (TILs) are an important component of the immune response to cancer and have a prognostic value in breast cancer. Although several studies have investigated the role of T lymphocytes in breast cancer, the role of B lymphocytes (TIL-Bs) in ductal carcinoma in situ (DCIS) remains uncertain. This study aimed to assess the role of TIL-Bs in DCIS.

METHODS AND RESULTS

Eighty DCIS cases (36 pure DCIS and 44 mixed with invasive cancer) were stained immunohistochemically for B lineage markers CD19, CD20 and the plasma cell marker CD138. TIL-Bs density and localization were assessed, including relation to the in-situ and invasive components. An association with clinicopathological data and patient outcome was performed. Pure DCIS showed a higher number of TIL-Bs and lymphoid aggregates than DCIS associated with invasion. In pure DCIS, a higher number of peri- and paratumoral TIL-Bs was associated significantly with large tumour size (P = 0.016), hormone receptor (ER/PR) negative (P = 0.008) and HER2⁺ status (P = 0.010). In tumours with mixed DCIS and invasive components, cases with high-density B lymphocytes, irrespective of their location or topographic distribution, were associated significantly with variables of poor prognosis, including larger size, high grade, lymphovascular invasion, lymph node metastases, ER/PR-negative and HER2⁺ status. Outcome analysis showed that pure DCIS associated with higher numbers of B lymphocytes had shorter recurrence-free interval (P = 0.04); however, the association was not significant with the CD138⁺ plasma cell count (P = 0.07).

CONCLUSION

Assessment of TIL-B cells based on location and topographic distribution can provide prognostic information. Validation in a larger cohort is warranted.

Identifying progression predictors of breast ductal carcinoma in situ

Ductal carcinoma in situ (DCIS) refers to neoplastic epithelial cells proliferating within the mammary ducts of the breast, which have not breached the basement membrane nor invaded surrounding tissues. Traditional thinking holds that DCIS represents an early step in a linear progression towards invasive ductal carcinoma (IDC). However, as only approximately half of DCIS cases progress to IDC, important questions around the key determinants of malignant progression need to be answered. Recent studies have revealed that molecular differences between DCIS and IDC cells are not found at the genomic level; instead, altered patterns of gene expression and post-translational regulation lead to distinct transcriptomic and proteomic profiles. Therefore, understanding malignant progression will require a different approach that takes into account the diverse tumour cell extrinsic factors driving changes in tumour cell gene expression necessary for the invasive phenotype. Here, we review the roles of the tumour stroma (including mesenchymal cells, immune cells and the extracellular matrix) and myoepithelial cells in malignant progression and make a case for a more integrated approach to the study and assessment of DCIS and its progression, or lack thereof, to invasive disease.