Clinicopathological Significance of Cyclin-Dependent Kinase 2 (CDK2) in Ductal Carcinoma In Situ and Early-Stage Invasive Breast Cancers.

Cyclin-dependent kinase 2 (CDK2) is a key cell cycle regulator, with essential roles during G1/S transition. The clinicopathological significance of CDK2 in ductal carcinomas in situ (DCIS) and early-stage invasive breast cancers (BCs) remains largely unknown. Here, we evaluated CDK2's protein expression in 479 BC samples and 216 DCIS specimens. Analysis of CDK2 transcripts was completed in the METABRIC cohort (n = 1980) and TCGA cohort (n = 1090), respectively. A high nuclear CDK2 protein expression was significantly associated with aggressive phenotypes, including a high tumour grade, lymph vascular invasion, a poor Nottingham prognostic index (all p-values < 0.0001), and shorter survival (p = 0.006), especially in luminal BC (p = 0.009). In p53-mutant BC, high nuclear CDK2 remained linked with worse survival (p = 0.01). In DCIS, high nuclear/low cytoplasmic co-expression showed significant association with a high tumour grade (p = 0.043), triple-negative and HER2-enriched molecular subtypes (p = 0.01), Comedo necrosis (p = 0.024), negative ER status (p = 0.004), negative PR status (p < 0.0001), and a high proliferation index (p < 0.0001). Tumours with high CDK2 transcripts were more likely to have higher expressions of genes involved in the cell cycle, homologous recombination, and p53 signaling. We provide compelling evidence that high CDK2 is a feature of aggressive breast cancers. The clinical evaluation of CDK2 inhibitors in early-stage BC patients will have a clinical impact.

Progression from ductal carcinoma in situ to invasive breast cancer: molecular features and clinical significance.

Ductal carcinoma in situ (DCIS) represents pre-invasive breast carcinoma. In untreated cases, 25-60% DCIS progress to invasive ductal carcinoma (IDC). The challenge lies in distinguishing between non-progressive and progressive DCIS, often resulting in over- or under-treatment in many cases. With increasing screen-detected DCIS in these years, the nature of DCIS has aroused worldwide attention. A deeper understanding of the biological nature of DCIS and the molecular journey of the DCIS-IDC transition is crucial for more effective clinical management. Here, we reviewed the key signaling pathways in breast cancer that may contribute to DCIS initiation and progression. We also explored the molecular features of DCIS and IDC, shedding light on the progression of DCIS through both inherent changes within tumor cells and alterations in the tumor microenvironment. In addition, valuable research tools utilized in studying DCIS including preclinical models and newer advanced technologies such as single-cell sequencing, spatial transcriptomics and artificial intelligence, have been systematically summarized. Further, we thoroughly discussed the clinical advancements in DCIS and IDC, including prognostic biomarkers and clinical managements, with the aim of facilitating more personalized treatment strategies in the future. Research on DCIS has already yielded significant insights into breast carcinogenesis and will continue to pave the way for practical clinical applications.

Prediction of coexisting invasive carcinoma on ductal carcinoma in situ (DCIS) lesions by mass spectrometry imaging.

Due to limited biopsy samples, ~20% of DCIS lesions confirmed by biopsy are upgraded to invasive ductal carcinoma (IDC) upon surgical resection. Avoiding underestimation of IDC when diagnosing DCIS has become an urgent challenge in an era discouraging overtreatment of DCIS. In this study, the metabolic profiles of 284 fresh frozen breast samples, including tumor tissues and adjacent benign tissues (ABTs) and distant surrounding tissues (DSTs), were analyzed using desorption electrospray ionization-mass spectrometry (DESI-MS) imaging. Metabolomics analysis using DESI-MS data revealed significant differences in metabolite levels, including small-molecule antioxidants, long-chain polyunsaturated fatty acids (PUFAs) and phospholipids between pure DCIS and IDC. However, the metabolic profile in DCIS with invasive carcinoma components clearly shifts to be closer to adjacent IDC components. For instance, DCIS with invasive carcinoma components showed lower levels of antioxidants and higher levels of free fatty acids compared to pure DCIS. Furthermore, the accumulation of long-chain PUFAs and the phosphatidylinositols (PIs) containing PUFA residues may also be associated with the progression of DCIS. These distinctive metabolic characteristics may offer valuable indications for investigating the malignant potential of DCIS. By combining DESI-MS data with machine learning (ML) methods, various breast lesions were discriminated. Importantly, the pure DCIS components were successfully distinguished from the DCIS components in samples with invasion in postoperative specimens by a Lasso prediction model, achieving an AUC value of 0.851. In addition, pixel-level prediction based on DESI-MS data enabled automatic visualization of tissue properties across whole tissue sections. Summarily, DESI-MS imaging on histopathological sections can provide abundant metabolic information about breast lesions. By analyzing the spatial metabolic characteristics in tissue sections, this technology has the potential to facilitate accurate diagnosis and individualized treatment of DCIS by inferring the presence of IDC components surrounding DCIS lesions. © 2023 The Pathological Society of Great Britain and Ireland.

Survivin Expression in Luminal Breast Cancer and Adjacent Normal Tissue for Immuno-Oncology Applications.

Survivin (BIRC5) is a tumor-associated antigen (TAA) overexpressed in various tumors but present at low to undetectable levels in normal tissue. Survivin is known to have a high expression in breast cancer (e.g., Ductal Carcinoma in situ (DCIS) and triple negative breast cancer). Previous studies have not compared survivin expression levels in DCIS tumor samples to levels in adjacent, normal breast tissue from the same patient. To ensure the effective use of survivin as a target for T cell immunotherapy of breast cancer, it is essential to ascertain the varying levels of survivin expression between DCIS tumor tissue samples and the adjacent normal breast tissue taken from the same patient simultaneously. Next-generation sequencing of RNA (RNA-seq) in normal breast tissue and tumor breast tissue from five women presenting with DCIS for lumpectomy was used to identify sequence variation and expression levels of survivin. The identity of both tumor and adjacent normal tissue samples were corroborated by histopathology. Survivin was overexpressed in human breast tissue tumor samples relative to the corresponding adjacent human normal breast tissue. Wild-type survivin transcripts were the predominant species identified in all tumor tissue sequenced. This study demonstrates upregulated expression of wild type survivin in DCIS tumor tissue versus normal breast tissue taken from the same patient at the same time, and provides evidence that developing selective cytotoxic T lymphocyte (CTL) immunotherapy for DCIS targeting survivin warrants further study.

Dendritic Cell Subpopulations Are Associated with Morphological Features of Breast Ductal Carcinoma In Situ.

Ductal carcinoma in situ (DCIS) is the preinvasive form of breast cancer (BC). It is disputed whether all cases of DCIS require extensive treatment as the overall risk of progression to BC is estimated at 40%. Therefore, the crucial objective for researchers is to identify DCIS with significant risk of transformation into BC. Dendritic cells (DC) are professional antigen presenting cells and as such play a pivotal role in the formation of immune cells that infiltrate in breast tumors. The aim of this study was to investigate the relationship between the density of DCs with different superficial antigens (CD1a, CD123, DC-LAMP, DC-SIGN) and various histopathological characteristics of DCIS. Our evaluation indicated that CD123+ and DC-LAMP+ cells were strongly associated with maximal tumor size, grading and neoductgenesis. Together with CD1a+ cells, they were negatively correlated with hormonal receptors expression. Furthermore, the number of DC-LAMP+ cells was higher in DCIS with comedo necrosis, ductal spread, lobular cancerization as well as comedo-type tumors, while CD1a+ cells were abundant in cases with Paget disease. We concluded that different subpopulations of DCs relate to various characteristics of DCIS. Of the superficial DCs markers, DC-LAMP seems particularly promising as a target for further research in this area.

Computer Vision Identifies Recurrent and Nonrecurrent Ductal Carcinoma in Situ Lesions with Special Emphasis on African-American Women.

Although nonrecurrent and recurrent forms of ductal carcinoma in situ (DCIS) of the breast are observed, no evidence-based test can make this distinction. The current retrospective case-control study used archival DCIS samples stained with anti-phospho-Ser226-glucose transporter type 1 and anti-phosphofructokinase type L antibodies. Immunofluorescence micrographs were used to create machine learning models of recurrent and nonrecurrent biomarker patterns, which were evaluated in cross-validation studies. Clinical performance was assessed by holdout studies using patients whose data were not used in training. Micrographs were stratified according to the recurrence probability of each image. Recurrent patients were defined by at least one image with a probability of recurrence ≥98%, whereas nonrecurrent patients had none. These studies found no false-negatives, identified true-positives, and uniquely identified true-negatives. Roughly 20% of the microscope fields of recurrent lesions were computationally recurrent. Strong prognostic results were obtained for both white and African-American women. This machine tool provides the first means to accurately predict recurrent and nonrecurrent patient outcomes. Data indicate that at least some false-positive findings were true-positive findings that benefited from surgical intervention. The intracellular locations of phospho-Ser226-glucose transporter type 1 and phosphofructokinase type L likely participate in cancer recurrences by accelerating glucose flux, a key feature of the Warburg effect.

A bicellular fluorescent ductal carcinoma in situ (DCIS)-like tumoroid to study the progression of carcinoma: practical approaches and optimization.

Recently, many types of 3D culture systems have been developed to preserve the physicochemical environment and biological characteristics of the original tumors better than the conventional 2D monolayer culture system. There are various types of models belonging to this culture, such as the culture based on non-adherent and/or scaffold-free matrices to form the tumors. Agarose mold has been widely used to facilitate tissue spheroid assembly, as it is essentially non-biodegradable, bio-inert, biocompatible, low-cost, and low-attachment material that can promote cell spheroidization. As no studies have been carried out on the development of a fluorescent bicellular tumoroid mimicking ductal carcinoma in situ (DCIS) using human cell lines, our objective was to detail the practical approaches developed to generate this model, consisting of a continuous layer of myoepithelial cells (MECs) around a previously formed in situ breast tumor. The practical approaches developed to generate a bi-cellular tumoroid mimicking ductal carcinoma in situ (DCIS), consisting of a continuous layer of myoepithelial cells (MECs) around a previously formed in situ breast tumoroid. Firstly, the optimal steps and conditions of spheroids generation using a non-adherent agarose gel were described, in particular, the appropriate medium, seeding density of each cell type and incubation period. Next, a lentiviral transduction approach to achieve stable fluorescent protein expression (integrative system) was used to characterize the different cell lines and to track tumoroid generation through immunofluorescence, the organization of the two cell types was validated, specific merits and drawbacks were compared to lentiviral transduction. Two lentiviral vectors expressing either EGFP (Enhanced Green Fluorescent Protein) or m-Cherry (Red Fluorescent Protein) were used. Various rates of a multiplicity of infection (MOI) and multiple types of antibodies (anti-p63, anti-CK8, anti-Maspin, anti-Calponin) for immunofluorescence analysis were tested to determine the optimal conditions for each cell line. At MOI 40 (GFP) and MOI 5 (m-Cherry), the signals were almost homogeneously distributed in the cells which could then be used to generate the DCIS-like tumoroids. Images of the tumoroids in agarose molds were captured with a confocal microscope Micro Zeiss Cell Observer Spinning Disk or with IncuCyte® to follow the progress of the generation. Measurement of protumoral cytokines such as IL-6, IL8 and leptin confirmed their secretion in the supernatants, indicating that the properties of our cells were not altered. Finally the advantages and disadvantages of each fluorescent approach were discussed. This model could also be used for other solid malignancies to study the complex relationship between different cells such as tumor and myoepithelial cells in various microenvironments (inflammatory, adipose and tumor, obesity, etc.). Although, this new model is well established to monitor drug screening applications and perform pharmacokinetic and pharmacodynamic analyses.

Molecular classification and biomarkers of clinical outcome in breast ductal carcinoma in situ: Analysis of TBCRC 038 and RAHBT cohorts.

Ductal carcinoma in situ (DCIS) is the most common precursor of invasive breast cancer (IBC), with variable propensity for progression. We perform multiscale, integrated molecular profiling of DCIS with clinical outcomes by analyzing 774 DCIS samples from 542 patients with 7.3 years median follow-up from the Translational Breast Cancer Research Consortium 038 study and the Resource of Archival Breast Tissue cohorts. We identify 812 genes associated with ipsilateral recurrence within 5 years from treatment and develop a classifier that predicts DCIS or IBC recurrence in both cohorts. Pathways associated with recurrence include proliferation, immune response, and metabolism. Distinct stromal expression patterns and immune cell compositions are identified. Our multiscale approach employed in situ methods to generate a spatially resolved atlas of breast precancers, where complementary modalities can be directly compared and correlated with conventional pathology findings, disease states, and clinical outcome.

MYO10-filopodia support basement membranes at pre-invasive tumor boundaries.

Ductal carcinoma in situ (DCIS) is a pre-invasive stage of breast cancer. During invasion, the encapsulating DCIS basement membrane (BM) is compromised, and tumor cells invade the surrounding stroma. The mechanisms that regulate functional epithelial BMs in vivo are poorly understood. Myosin-X (MYO10) is a filopodia-inducing protein associated with metastasis and poor clinical outcome in invasive breast cancer (IBC). We identify elevated MYO10 expression in human DCIS and IBC, and this suggests links with disease progression. MYO10 promotes filopodia formation and cell invasion in vitro and cancer-cell dissemination from progressively invasive human DCIS xenografts. However, MYO10-depleted xenografts are more invasive. These lesions exhibit compromised BMs, poorly defined borders, and increased cancer-cell dispersal and EMT-marker-positive cells. In addition, cancer spheroids are dependent on MYO10-filopodia to generate a near-continuous extracellular matrix boundary. Thus, MYO10 is protective in early-stage breast cancer, correlating with tumor-limiting BMs, and pro-invasive at later stages, facilitating cancer-cell dissemination.

Aurora Kinase A Is an Independent Predictor of Invasive Recurrence in Breast Ductal Carcinoma in situ.

INTRODUCTION: Aurora Kinase A (AURKA/STK15) has a role in centrosome duplication and is a regulator of mitotic cell proliferation. It is over-expressed in breast cancer and other cancers, however; its role in ductal carcinoma in situ (DCIS) remains to be defined. This study aims to characterize AURKA protein expression in DCIS and evaluate its prognostic significance. METHODS: AURKA was assessed immunohistochemically in a large well-characterized cohort of DCIS (n = 776 pure DCIS and 239 DCIS associated with invasive breast cancer [DCIS-mixed]) with long-term follow-up data (median = 105 months) and basic molecular characterization. RESULTS: High AURKA expression was observed in 15% of DCIS cases and was associated with features of aggressiveness including larger tumour size, high nuclear grade, hormone receptor negativity, HER2 positivity, and high Ki67 proliferation index. AURKA expression was higher in DCIS associated with invasive breast cancer than in pure DCIS (p < 0.0001). In the DCIS-mixed cohort, the invasive component showed higher AURKA expression than the DCIS component (p < 0.0001). Outcome analysis revealed that AURKA was a predictor of invasive recurrence (p = 0.002). CONCLUSION: High AURKA expression is associated with poor prognosis in DCIS and might be a potential marker to predict DCIS progression to invasive disease.

The heparan sulphate proteoglycan Syndecan-1 (CD138) regulates tumour progression in a 3D model of ductal carcinoma in situ of the breast.

Ductal carcinoma in situ (DCIS) is a form of breast cancer that is restricted to the lactiferous ducts and has not yet invaded the surrounding breast tissue. Dysregulation of the transmembrane heparan sulphate proteoglycan Syndecan-1 (Sdc-1) plays a role in tumour progression of invasive breast cancer (IBC). In DCIS, Sdc-1, c-Met and E-cadherin are part of a proangiogenic expression signature. In this study, we employed a siRNA knockdown approach in the DCIS model cell line MCF10A DCIS.com to investigate a potential connection between Sdc-1 and epithelial mesenchymal transition (EMT), proteolysis and the Rho kinase pathway. Analysis of gene expression data of the TNMplot.com database revealed that Sdc-1 expression was higher in primary breast tumours compared to metastases. The impact of Sdc-1-depletion on the cellular phenotype was investigated in a Matrigel-based three-dimensional cell culture model. Sdc-1 depletion resulted in the formation of larger spheroids and the formation of invasive protrusions. Application of matrix metalloproteinase (MMP) and Rho kinase inhibitors could block the Sdc-1-induced phenotype. qPCR analysis of Sdc-1-depleted cells in two-dimensional culture revealed upregulated expression of the EMT-markers CDH1, FN-1, CLDN1, the proteolysis markers MMP3, and MMP9, and HPSE, while MMP2, VIM and ROCK-2 were downregulated. Immunocytochemistry confirmed upregulation of MMP9 and fibronectin, the latter being particular prominent after ROCK inhibition. STRING analysis confirmed an interaction of the investigated gene products at the protein level. Our results suggest that diminished Sdc-1 expression plays a role in DCIS progression to IBC through deregulation of proteolytic factors and a partial EMT.

Expression Profile of Myoepithelial Cells in DCIS: Do They Change From Protective Angels to Wicked Witches?

The mechanism of transition of ductal carcinoma in situ (DCIS) to invasive cancer is elusive but recently changes in the myoepithelial cells (MECs) have been implicated. The aim of this study is to investigate the changes in gene profile of MECs in DCIS that could compromise their tumor suppressor function leading to promotion of tumor progression. Immuno-laser capture microdissection (LCM) was used to isolate MECs from normal and DCIS breast tissues followed by whole genome expression profiling using Affymetrix HGU-133 plus2.0 arrays. The data were analyzed using Bioconductor packages then validated by using real-time quantitative polymerase chain reaction and immunohistochemistry. Ingenuity Pathways software analysis showed clustering of most of the altered genes in cancer and cell death networks, with the Wnt/B-catenin pathway as the top canonical pathway. Validation revealed a 71.4% correlation rate with the array results. Most dramatic was upregulation of Fibronectin 1 ( FN1 ) in DCIS-associated MECs. Immunohistochemistry analysis for FN1 on normal and DCIS tissues confirmed a strong correlation between FN1 protein expression by MECs and DCIS ( P <0.0001) and between high expression level and presence of invasion ( P =0.006) in DCIS. Other validated alterations in MEC expression profile included upregulation of Nephronectin and downregulation of parathyroid hormone like hormone ( PTHLH ), fibroblast growth factor receptor 2 ( FGFR2 ), ADAMTS5 , TGFBR3 , and CAV1 . In vitro experiments revealed downregulation of PTHLH in DCIS-modified MECs versus normal lines when cultured on Fibronectin matrix. This is the first study to use this in vivo technique to investigate molecular changes in MECs in DCIS. This study adds more evidences to the molecular deviations in MECs toward tumor progression in DCIS through upregulation of the tumor-promoting molecules that may lead to novel predictive and therapeutic targets.

Regulation of growth, invasion and metabolism of breast ductal carcinoma through CCL2/CCR2 signaling interactions with MET receptor tyrosine kinases.

With over 60,000 cases diagnosed annually in the US, ductal carcinoma in situ (DCIS) is the most prevalent form of early-stage breast cancer. Because many DCIS cases never progress to invasive ductal carcinomas (IDC), overtreatment remains a significant problem. Up to 20% patients experience disease recurrence, indicating that standard treatments do not effectively treat DCIS for a subset of patients. By understanding the mechanisms of DCIS progression, we can develop new treatment strategies better tailored to patients. The chemokine CCL2 and its receptor CCR2 are known to regulate macrophage recruitment during inflammation and cancer progression. Recent studies indicate that increased CCL2/CCR2 signaling in breast epithelial cells enhance formation of IDC. Here, we characterized the molecular mechanisms important for CCL2/CCR2-mediated DCIS progression. Phospho-protein array profiling revealed that CCL2 stimulated phosphorylation of MET receptor tyrosine kinases in breast cancer cells. Co-immunoprecipitation and proximity ligation assays demonstrated that CCL2-induced MET activity depended on interactions with CCR2 and SRC. Extracellular flux analysis and biochemical assays revealed that CCL2/CCR2 signaling in breast cancer cells enhanced glycolytic enzyme expression and activity. CRISPR knockout and pharmacologic inhibition of MET revealed that CCL2/CCR2-induced breast cancer cell proliferation, survival, migration and glycolysis through MET-dependent mechanisms. In animals, MET inhibitors blocked CCR2-mediated DCIS progression and metabolism. CCR2 and MET were significantly co-expressed in patient DCIS and IDC tissues. In summary, MET receptor activity is an important mechanism for CCL2/CCR2-mediated progression and metabolism of early-stage breast cancer, with important clinical implications.

Assessment of Ki-67 proliferation index with deep learning in DCIS (ductal carcinoma in situ).

The proliferation index (PI) is crucial in histopathologic diagnostics, in particular tumors. It is calculated based on Ki-67 protein expression by immunohistochemistry. PI is routinely evaluated by a visual assessment of the sample by a pathologist. However, this approach is far from ideal due to its poor intra- and interobserver variability and time-consuming. These factors force the community to seek out more precise solutions. Virtual pathology as being increasingly popular in diagnostics, armed with artificial intelligence, may potentially address this issue. The proposed solution calculates the Ki-67 proliferation index by utilizing a deep learning model and fuzzy-set interpretations for hot-spots detection. The obtained region-of-interest is then used to segment relevant cells via classical methods of image processing. The index value is approximated by relating the total surface area occupied by immunopositive cells to the total surface area of relevant cells. The achieved results are compared to the manual calculation of the Ki-67 index made by a domain expert. To increase results reliability, we trained several models in a threefold manner and compared the impact of different hyper-parameters. Our best-proposed method estimates PI with 0.024 mean absolute error, which gives a significant advantage over the current state-of-the-art solution.

LncRNA IPW inhibits growth of ductal carcinoma in situ by downregulating ID2 through miR-29c.

BACKGROUND: Ductal carcinoma in situ (DCIS) of breast is the noninvasive lesion that has propensity to progress to the malignant form. At present, it is still unknown which lesions can potentially progress to invasive forms. In this study, we aimed to identify key lncRNAs involved in DCIS growth. METHODS: We employ disease-related lncProfiler array to identify IPW in specimens of DCIS and matching control samples and validate the observations in three DCIS-non-tumorigenic cell lines. Further, we examine the mechanism of IPW action and the downstream signaling in in vitro and in vivo assays. Importantly, we screened a library containing 390 natural compounds to identify candidate compound selectively inhibiting IPW low DCIS cells. RESULTS: We identified lncRNA IPW as a novel tumor suppressor critical for inhibiting DCIS growth. Ectopic expression of IPW in DCIS cells strongly inhibited cell proliferation, colony formation and cell cycle progression while silencing IPW in primary breast cells promoted their growth. Additionally, orthotropic implantation of cells with ectopic expression of IPW exhibited decreased tumor growth in vivo. Mechanistically, IPW epigenetically enhanced miR-29c expression by promoting H3K4me3 enrichment in its promoter region. Furthermore, we identified that miR-29c negatively regulated a stemness promoting gene, ID2, and diminished self-renewal ability of DCIS cells. Importantly, we screened a library containing 390 natural compounds and identified toyocamycin as a compound that selectively inhibited the growth of DCIS with low expression of IPW, while it did not affect DCIS with high IPW expression. Toyocamycin also suppressed genes associated with self-renewal ability and inhibited DCIS growth in vivo. CONCLUSION: Our findings revealed a critical role of the IPW-miR-29c-ID2 axis in DCIS formation and suggested potential clinical use of toyocamycin for the treatment of DCIS.

Can We Successfully De-Escalate Axillary Surgery in Women Aged ≥ 70 Years with Ductal Carcinoma in Situ or Early-Stage Breast Cancer Undergoing Mastectomy?

BACKGROUND: Omission of sentinel lymph node biopsy (SLNB) in older women with clinically node-negative, hormone receptor-positive (HR+) early-stage breast cancer undergoing lumpectomy is accepted, given established low rates of regional recurrence. The safety of omitting SLNB in women undergoing mastectomy is unknown and may differ depending on extent of breast disease and variation in radiotherapy use. PATIENTS AND METHODS: From 2006 to 2018, 123 cTis and 328 cT1-2 HR+/HER2- tumors from 410 women aged ≥ 70 years who underwent mastectomy and SLNB were included (41 bilateral cases). The rate of nodal positivity and effect of nodal positivity on adjuvant therapy use were examined. RESULTS: Median age was 74 years; 21% of patients had positive sentinel lymph nodes, 7% had micrometastases, and 14% had macrometastases. Of cases of cTis tumors, 31% were upstaged to invasive carcinoma; 1% had macrometastases. Fewer cases of cT1 than cT2 tumors had macrometastases [13% (26/200) versus 29% (37/128); p < 0.001]. Eight percent of patients with pT1 tumors (18/228) and 27% of patients with pT2 tumors (30/113) received chemotherapy. Most patients with pT1, pN1 disease (78%; 25/32) did not receive chemotherapy. Rates of locoregional recurrence were similar between patients with cT1 or cT2 tumors with and without nodal metastases (median follow-up, 4.5 years). CONCLUSIONS: Women aged ≥ 70 years with cTis and cT1N0 HR+/HER2- tumors who underwent mastectomy had low rates of nodal positivity, similar to rates reported for lumpectomy. Given this and the RxPONDER results, omission of SLNB may be considered, as findings are unlikely to alter adjuvant therapy recommendations.

Accounting for Preinvasive Conditions in Analysis of Invasive Cancer Risk: Application to Breast Cancer.

BACKGROUND: Preinvasive cancer conditions are often actively treated to minimize progression to life-threatening invasive cancers, but this creates challenges for analysis of invasive cancer risk. Conventional methods of treating preinvasive conditions as censoring events or targeting at the composite outcome could both lead to bias. METHODS: We propose two solutions: one that provides exact estimates of risk based on distributional assumptions about progression, and one that provides risk bounds corresponding to extreme cases of no or complete progression. We compare these approaches through simulations and an analysis of the Sister Study data in the context of ductal carcinoma in situ (DCIS) and invasive breast cancer. RESULTS: Simulations suggested important biases with conventional approaches, whereas the proposed estimate is consistent when progression parameters are correctly specified, and the risk bounds are robust in all scenarios. With Sister Study, the estimated lifetime risks for invasive breast cancer are 0.220 and 0.269 with DCIS censored or combined. Without detailed progression information, a sensitivity analysis suggested lifetime risk falls between the bounds of 0.214 and 0.269 across assumptions of 10%-95% of DCIS patients progressing to invasive cancer in an average of 1-10 years. CONCLUSIONS: When estimating invasive cancer risk while preinvasive conditions are actively treated, it is important to consider the implied assumptions and potential biases of conventional approaches. Although still not perfect, we proposed two practical solutions that provide improved understanding of the underlying mechanism of invasive cancer.

Histological and immunohistochemical investigation of canine prostate carcinoma with identification of common intraductal carcinoma component.

A limited number of species, including men and dogs, spontaneously develop prostate cancer (PC). The histological and molecular relevance of canine PC as a model for the disease in men remains controversial. To address this challenge, this study aimed to assess the histomorphology and expression of basal cell, urothelial and neuroendocrine markers [p63, high molecular weight cytokeratin (HMWCK), Uroplakin 3 (UPIII), neuron-specific enolase (NSE)] in canine PC (n = 41). Based on histomorphology, 10/41 (24%), 21/41 (51%) and 9/41 (22%) were classified as adenocarcinoma (AC), urothelial carcinoma (UC), and mixed carcinoma, respectively. Tumour inflammation was common, frequently severe [20/41 (49%)], and associated with neutering (p < .02) and urothelial differentiation (p < .02). Most (36/40, 90%) cancers contained only rare cells with basal cell marker expression or were negative. The expression of UPIII was absent or weak in the majority (33/38, 87%) of tumours, with moderate to strong staining in the remaining cases. NSE expression in PC was rare and limited to 2/14 (14%) cases. Tumour extension into benign ducts and glands was a common finding with presence in 17/39 (44%) of carcinomas with and without urothelial differentiation. In conclusion, we confirm that canine PC is characterized by absent or weak expression of basal cell and urothelial markers. Although rare, NSE expression, potentially indicating neuroendocrine differentiation, is reported for the first time in canine PCa. Intraductal carcinoma of the prostate with concurrent invasive PCa (IDCP-inv) is a frequent, not previously described, finding in dogs with PC.

Ultrasound evaluation of ductal carcinoma in situ of the breast.

PURPOSE: To assess the role of ultrasound (US) in detecting and characterizing ductal carcinoma in situ (DCIS) of the breast and to investigate the correlation between ultrasonographic and biological features of DCIS. METHODS: In total, 171 patients (mean age 44; range 39-62) with 178 lesions were retrospectively evaluated by two independent radiologists searching for US mass or non-mass lesions. Immunohistochemistry analysis was performed to determine estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. The US detection rate and pattern distribution among the lesion types were evaluated. The χ2 test was used to evaluate the correlation between the US findings and the biological factors. Statistical significance was indicated by p values < 0.05. Inter-observer agreement was calculated by Kohen's k test. RESULTS: US detected 35% (63/178) of all lesions. Fifty-two (83%) lesions were classified as mass lesions, and 11 (17%) as non-mass lesions (p < 0.0001). Among the mass lesions, the most common shape was irregular (79%; p < 0.0001), with 45 (87%) lesions having indistinct margins. Hypoechogenicity was the most common echo pattern (49 cases, 94%; p < 0.0001). Microcalcifications were found in 23 cases (37%; p = 0.004) and were associated with mass lesions in 15 cases (65%) and with non-mass lesions in 8 cases (35%) (p = 0.21). An almost perfect inter-observer agreement (k = 0.87) was obtained between the two radiologists. A significant ER expression was found in mass lesions (83%; p < 0.0001), with no significant PR (p = 0.89) or HER2 expression (p = 0.81). Among the lesions with microcalcifications, only 7 out of 23 cases (30%) were positive for HER2 (p = 0.09). CONCLUSION: DCIS represents a heterogeneous pathological process with variable US appearance (mass-like, non-mass-like, or occult). The most common US finding is represented by mass-type, hypoechogenic lesions with indistinct margins. A significant ER expression exists among mass-type lesions, while microcalcifications seem not to be associated with HER2 expression.