Characterization and spatial distribution of the immune cell infiltrate in triple-negative breast cancer: a novel classification based on plasma cells and CD8+ T cells

The prognostic value of the tumor-stroma ratio compared to tumor-infiltrating lymphocytes in triple-negative breast cancer: a review

Previous literature extensively explored biomarkers to personalize treatment for breast cancer patients. The clinical need is especially high in patients with triple-negative breast cancer (TNBC) due to its aggressive nature and limited treatment modalities. This review aims to evaluate the value of tumor-infiltrating lymphocytes (TILs) and tumor-stroma ratio (TSR) as prognostic biomarkers in TNBC patients and assess their clinical potential. A literature search was conducted in PubMed, Embase, Emcare, Web of Science, and Cochrane Library. Papers comparing survival outcomes of TNBC patients with low/high or negative/positive TSR and immune cells were included. The most frequently mentioned subgroups of TILs were selected and reported in this review. Data from 43 articles on TILs and eight articles on TSR were included. Among TNBC patients, high CD8 expression was generally associated with better survival. Notable, the poor survival outcomes were related to high intra-tumoral PD-L1 expression, whereas high stromal PD-L1 expression more often was correlated with favorable outcomes. For the TSR, a high amount of stroma in the primary tumor of TNBC patients was consistently associated with worse survival. This review highlights that a high number of CD8-positive T-cells is a promising prognostic factor for TNBC patients. PD-L1 expression analyzed for intra-tumoral and stromal expression separately reports strong but contrasting information. Finally, the TSR shows potential to be an important prognostic marker, especially for TNBC patients. Utilizing both biomarkers, either on itself or combined, could enhance clinical decision-making and personalization of treatment.

Hypomethylating agents as emerging therapeutics for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is recognized as the most aggressive subtype of breast cancer. Epigenetic silencing, such as DNA methylation mediated by DNA methyltransferases (DNMTs) plays key roles in TNBC tumorigenesis. Hypomethylating agents (HMAs) such as azacitidine, decitabine, and guadecitabine are key inhibitors of DNMTs, and accumulating evidence has shown their immunogenicity properties. In this review, the efficacy and anti-tumor immune responses triggered by HMAs in TNBC are presented and discussed. Essentially, overexpression of DNMTs is associated with poor prognosis and reduced TNBC survival rates, and these effects are negated by HMAs. In particular, HMAs could reverse epigenetic silencing of tumor suppressor genes and enhance immune recognition of TNBC cells. Clinical trials of HMAs in TNBCs are limited but early-stage trials indicate that HMAs are safe and tolerable. More clinical studies are required to establish the effectiveness of HMAs against the disease, as supported by preclinical data substantiating their effectiveness especially guadecitabine. Future research should focus on optimizing dosing and exploring combinations with immunotherapies to maximize the potential of HMAs in TNBC treatment.

Tertiary lymphoid structures in cancer: immune mechanisms and clinical implications

Cancer is a major cause of death globally, and traditional treatments often have limited efficacy and adverse effects. Immunotherapy has shown promise in various malignancies but is less effective in tumors with low immunogenicity or immunosuppressive microenvironment, especially sarcomas. Tertiary lymphoid structures (TLSs) have been associated with a favorable response to immunotherapy and improved survival in cancer patients. However, the immunological mechanisms and clinical significance of TLS in malignant tumors are not fully understood. In this review, we elucidate the composition, neogenesis, and immune characteristics of TLS in tumors, as well as the inflammatory response in cancer development. An in-depth discussion of the unique immune characteristics of TLSs in lung cancer, breast cancer, melanoma, and soft tissue sarcomas will be presented. Additionally, the therapeutic implications of TLS, including its role as a marker of therapeutic response and prognosis, and strategies to promote TLS formation and maturation will be explored. Overall, we aim to provide a comprehensive understanding of the role of TLS in the tumor immune microenvironment and suggest potential interventions for cancer treatment.