Intercepting Premalignant, Preinvasive Breast Lesions Through Vaccination.

Breast cancer (BC) prevention remains the ultimate cost-effective method to reduce the global burden of invasive breast cancer (IBC). To date, surgery and chemoprevention remain the main risk-reducing modalities for those with hereditary cancer syndromes, as well as high-risk non-hereditary breast lesions such as ADH, ALH, or LCIS. Ductal carcinoma in situ (DCIS) is a preinvasive malignant lesion of the breast that closely mirrors IBC and, if left untreated, develops into IBC in up to 50% of lesions. Certain high-risk patients with DCIS may have a 25% risk of developing recurrent DCIS or IBC, even after surgical resection. The development of breast cancer elicits a strong immune response, which brings to prominence the numerous advantages associated with immune-based cancer prevention over drug-based chemoprevention, supported by the success of dendritic cell vaccines targeting HER2-expressing BC. Vaccination against BC to prevent or interrupt the process of BC development remains elusive but is a viable option. Vaccination to intercept preinvasive or premalignant breast conditions may be possible by interrupting the expression pattern of various oncodrivers. Growth factors may also function as potential immune targets to prevent breast cancer progression. Furthermore, neoantigens also serve as effective targets for interception by virtue of strong immunogenicity. It is noteworthy that the immune response also needs to be strong enough to result in target lesion elimination to avoid immunoediting as it may occur in IBC arising from DCIS. Overall, if the issue of vaccine targets can be solved by interrupting premalignant lesions, there is a potential to prevent the development of IBC.

Indicators of a pro-tumor immune response are evident at early stages of breast cancer.

With advances in checkpoint inhibitor and CAR T-cell therapies, among other advances in immunotherapy, this is an exciting time to be a tumor immunologist. We are witnessing the transition of decades of work at the bench leading to substantial success in the clinic. While work continues developing new and improving existing immunotherapies, there remains a great deal of basic tumor immunology still to learn, information that can only lead to greater success in the clinic. One area in need of more attention is understanding the immune response at early stages of breast cancer. While there is no question that early diagnosis and treatment save lives, a greater understanding about the immune response during early stages of breast cancer may reveal information that could assist in monitoring individuals at risk of breast cancer, and could have implications for patients diagnosed at early stages of disease, and may provide important information about the origins of an immune-suppressive environment. Here, we review studies that have looked at the very early immune response to breast cancer focusing on patients with DCIS, before invasion in spontaneous transgenic murine mammary carcinoma models, and before transplantable or orthotopic murine mammary carcinoma models become palpable. The findings revealed that indicators of a pro-tumor immune response are already present at early stages of disease.

Rapid virtual hematoxylin and eosin histology of breast tissue specimens using a compact fluorescence nonlinear microscope.

Up to 40% of patients undergoing breast conserving surgery for breast cancer require repeat surgeries due to close to or positive margins. The lengthy processing required for evaluating surgical margins by standard paraffin-embedded histology precludes its use during surgery and therefore, technologies for rapid evaluation of surgical pathology could improve the treatment of breast cancer by reducing the number of surgeries required. We demonstrate real-time histological evaluation of breast cancer surgical specimens by staining specimens with acridine orange (AO) and sulforhodamine 101 (SR101) analogously to hematoxylin and eosin (H&E) and then imaging the specimens with fluorescence nonlinear microscopy (NLM) using a compact femtosecond fiber laser. A video-rate computational light absorption model was used to produce realistic virtual H&E images of tissue in real time and in three dimensions. NLM imaging could be performed to depths of 100 µm below the tissue surface, which is important since many surgical specimens require subsurface evaluation due to contamination artifacts on the tissue surface from electrocautery, surgical ink, or debris from specimen handling. We validate this method by expert review of NLM images compared to formalin-fixed, paraffin-embedded (FFPE) H&E histology. Diagnostically important features such as normal terminal ductal lobular units, fibrous and adipose stromal parenchyma, inflammation, invasive carcinoma, and in situ lobular and ductal carcinoma were present in NLM images associated with pathologies identified on standard FFPE H&E histology. We demonstrate that AO and SR101 were extracted to undetectable levels after FFPE processing and fluorescence in situ hybridization (FISH) HER2 amplification status was unaffected by the NLM imaging protocol. This method potentially enables cost-effective, real-time histological guidance of surgical resections.

Prognostic value of stromal tumour infiltrating lymphocytes and programmed cell death-ligand 1 expression in breast cancer.

AIM: The present work aims to evaluate the presence of stromal tumour-infiltrating lymphocytes (TILs) and programmed cell death-ligand 1 (PDL1) expression in breast carcinomas and their correlation with available clinicopathological features. METHODS: Two independent series of invasive breast cancer (IBC), one including ductal carcinoma in situ (DCIS) pair-matched cases, were selected, and quantification of TILs was accomplished in each case. Immunohistochemistry was also performed to evaluate the expression of PDL1. RESULTS: In both cohorts evaluated, increased stromal TILs and PDL1 expression were present in about 10% of IBCs, being significantly associated with each other and both with grade 3 and triple-negative subtype. We observed a similar distribution of stromal TILs and PDL1 expression between DCIS and IBC. Finally, we observed that increased stromal TILs and PDL1 expression were significantly associated with cancer stem cell (CSC) markers, basal cell markers and vimentin expression. Interestingly, in IBC cases with vimentin expression, increased stromal TILs, as well as decreased PDL1 expression, disclosed a better clinical outcome, independently of the main classical BC prognostic factors. CONCLUSIONS: We have confirmed the association of stromal TILs and PDL1 expression with aggressive forms of BC and that both are already found in in situ stages. We also showed that stromal TILs and PDL1 expression are associated with clinical outcome in cases enriched for a mesenchymal immunophenotype. We describe for the first time a close relationship between CSC markers and PDL1 expression.

Myoepithelial cells in lobular carcinoma in situ: distribution and immunophenotype.

Myoepithelial cells have important physical and paracrine roles in breast tissue development, maintenance, and tumor suppression. Recent molecular and immunohistochemical studies have demonstrated phenotypic alterations in ductal carcinoma in situ-associated myoepithelial cells. Although the relationship of lobular carcinoma in situ (LCIS) and myoepithelial cells was described in 1980, further characterization of LCIS-associated myoepithelial cells is lacking. We stained 27 breast specimens harboring abundant LCIS with antibodies to smooth muscle myosin heavy chain, smooth muscle actin, and calponin. Dual stains for E-cadherin/smooth muscle myosin heavy chain and CK7/p63 were also performed. In each case, the intensity and distribution of staining in LCIS-associated myoepithelial cells were compared with normal breast tissue on the same slide. In 78% of the cases, LCIS-associated myoepithelial cells demonstrated decreased staining intensity for one or more myoepithelial markers. The normal localization of myoepithelial cells (flat against the basement membrane, pattern N) was seen in 96% of LCIS, yet 85% of cases had areas with myoepithelial cell cytoplasm oriented perpendicular to the basement membrane (pattern P), and in 30% of cases, myoepithelial cells appeared focally admixed with LCIS cells (pattern C). This study characterizes detailed architectural and immunophenotypic alterations of LCIS-associated myoepithelial cells. The finding of variably diminished staining favors application of several myoepithelial immunostains in clinical practice. The interaction of LCIS with myoepithelial cells, especially in light of the perpendicular and central architectural arrangements, deserves further mechanistic investigation.