Expression In Ductal Carcinoma Research Articles

Spectrum of histopathologic findings in risk-reducing bilateral prophylactic mastectomy in patients with and without BRCA mutations

Many germline mutations have been implicated in breast cancer pathogenesis and despite several studies on occult atypical lesions in prophylactic mastectomy specimens from patients with BRCA1/2 mutations, there are very limited data on other genes associated with increased breast cancer risk and the distribution of lesions in patients with hereditary breast cancer. We identified 207 patients who underwent bilateral prophylactic mastectomy due to germline mutations in BRCA1/2, PALB2, CHEK2, ATM, CDH1, PTEN, BARD1, or strong family history between 2015 and 2023. Patients with biopsy-proven past or current invasive breast carcinoma or carcinoma in-situ preoperatively were excluded. In addition to multiple benign lesions, the following atypical lesions were identified: flat epithelial atypia (16.9%), atypical ductal hyperplasia (14.0%), lobular neoplasia (14.0%), ductal carcinoma in-situ (4.3%), invasive ductal carcinoma (0.4%). Both low-grade and high-grade pathway lesions were identified in this cohort, and in a subset of patients, they co-occurred. The frequency of atypical lesions identified in patients with strong family history were comparable to those with proven germline mutation. PTEN immunohistochemistry showed loss of expression in ductal carcinoma in-situ and tubular adenomas in PTEN-mutant patients. Overall, findings from this cohort support the benefit of prophylactic mastectomy in patients with germline mutations and/or strong family history. Additionally, this is the first demonstration that PTEN immunohistochemistry may be helpful in identifying germline mutations in patients with atypical or neoplastic proliferations.

51P Clinical and biological significance of low ERBB2 expression in ductal carcinoma in situ (DCIS) of the breast

51P Clinical and biological significance of low ERBB2 expression in ductal carcinoma in situ (DCIS) of the breast

Expression of HLA class I is associated with immune cell infiltration and patient outcome in breast cancer

Downregulation of human leukocyte antigen (HLA) class I is one mechanism of escaping anti-tumor immunity by tumor cells. This study was conducted to compare HLA class I expression in ductal carcinoma in situ (DCIS) and invasive breast carcinoma (IBC) and to evaluate its association with immune cell infiltration of the tumors and clinical outcome of the patients. A total of 830 cases comprising 288 DCIS and 542 IBC were included in this study. Immunohistochemistry for HLA class I expression was performed using HLA-ABC in tissue microarrays and was analyzed in relation to clinicopathologic characteristics of tumors and infiltration of CD4+, CD8+, and FOXP3+ tumor-infiltrating lymphocyte (TIL) subsets and PD-L1+ immune cells. As a whole, there was no difference in HLA class I expression between DCIS and IBC when dichotomized into high or low expression. However, in the HR-negative group, a high level of HLA class I expression was more frequent in IBC than DCIS. On the contrary, in the HR-positive group, a complete loss of HLA class I expression was more frequently observed in IBC than DCIS. High HLA class I expression level was generally associated with aggressive clinicopathologic features of IBC and was associated with high CD4+, CD8+, and FOXP3+ TIL and PD-L1+ immune cell infiltration in both DCIS and IBC. In survival analyses, HLA class I expression was not associated with clinical outcome in DCIS and IBC as a whole; however, low HLA class I expression was associated with poor clinical outcome in HR-negative IBC, especially in triple-negative subtype. In conclusion, this study showed that HLA class I expression increased in association with increased immune cell infiltration during in situ to invasive transition of HR-negative breast cancer, and HLA class I down-regulation had a prognostic value in HR-negative breast cancer.

Abstract P4-07-22: Evaluation of human epididymis protein 4 serum and tissue expression in ductal carcinoma in situ of the breast

Abstract Background: Human epididymis protein 4 (HE4), also known as WFDC2, is a member of whey acidic protein (WAP) family with a presumptive role in natural immunity. HE4 expression has been increased in many cancer types, particularly in gynecologic and pulmonary cancers. HE4 has been identified as an important serum biomarker in the diagnosis and monitoring of epithelial ovarian cancer. Recent researches have demonstrated that HE4 levels in serum and tissues are elevated in patients with breast cancer and HE4 is thought be involved in breast cancer progression. In contrast, expression of HE4 in ductal carcinoma in situ (DCIS) has not been well characterized yet. The present work was undertaken to evaluate serum and tissue levels of HE4 in DCIS and their correlations with clinicopathological features of DCIS. Materials and methods: Preoperative serum HE4 levels in 59 DCIS patients was analyzed using the ARCHITECT assay. Tissue microarray containing DCIS and adjacent normal tissues from the same cohort were tested for HE4 mRNA and protein by RNAscope in situ hybridization (ISH) and immunohistochemistry analysis, respectively. Tissue microarray containing only DCS tissues from 41 patients were also tested for HE4 mRNA and protein. To validate prognostic potential of HE4 in breast cancer patients, the BreastMark database was used. Results: HE4 levels in 59 DCIS patients ranged from 23.5 to 86.3 pmol/L (mean ± SD: 39.4 ± 11.9). Based on the cutoff level, there were no abnormal cases for HE4. Serum HE4 levels did not differ according to clinicopathological parameters except for menopause status. RNAscope ISH and immunohistochemistry confirmed an increase in HE4 in DCIS tissues compared with their corresponding normal tissues. Spearman’s correlation analyses revealed no significant correlation between serum and tissue levels of HE4. Among 100 DCIS tissues, there was a positive correlation between HE4 mRNA ISH scores and HE4 immunohistochemical staining scores (r = 0.771, P < 0.001). High mRNA and protein expression of HE4 were observed in 25 of 99 (25.3%) and 34 of 99 (34.3%) cases, respectively. High mRNA HE4 expression was significantly associated with low stromal tumor infiltrating lymphocyte (TIL) density scores, ER positivity, HER2 negativity, and HR+/HER2- subtype. High protein HE4 expression was also significantly associated with absence of comedo-type necrosis, low stromal TIL density scores, ER positivity, HER2 negativity, and HR+/HER2- subtype. HE4 mRNA and protein expression did not correlate with recurrence of DCIS. In breast cancer patients, high HE4 expression was significantly associated with good survival in the overall group (HR = 0.838, P = 0.003, n = 2,652) and lymph node negative group (HR = 0.791, P = 0.029, n = 1,183). Conclusions: Our study revealed that serum HE4 is not elevated in patients with DCIS. High expression of HE4 mRNA and protein in DCIS tissues are associated with good clinicopathological characteristics, which warrant. further investigations. Citation Format: Ji Shin Leee, Nah Ihm Kim, Min Ho Park. Evaluation of human epididymis protein 4 serum and tissue expression in ductal carcinoma in situ of the breast [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-07-22.

Stromal Changes are Associated with High P4HA2 Expression in Ductal Carcinoma in Situ of the Breast

Ductal carcinoma in situ (DCIS) of the breast is able to induce stromal changes, which likely reflect the crosstalk between DCIS and its microenvironment. These changes harbor prognostic information, although the interobserver variability of scoring stromal changes is moderate. A more robust evaluation of the DCIS-associated stroma is therefore needed. The aim of this study was to characterize P4HA2 expression, which is involved in collagen biosynthesis, in DCIS and to assess whether P4HA2 expression enables a more robust evaluation of the DCIS-associated stroma compared to histomorphology. This study included 410 patients with DCIS. Stromal changes were scored on hematoxylin/eosin-stained whole slides. P4HA2 expression in DCIS-associated stroma was assessed by whole slide immunohistochemistry. One hundred DCIS lesions were evaluated by seven pathologists to study the interobserver variability in the assessment of stromal changes and stromal P4HA2 expression. High P4HA2 expression in stromal fibroblasts was present in 14.1% of the patients. High P4HA2 expression was associated with the presence of periductal stromal changes (P = 0.004). The interobserver variability was similar for the assessment of stromal changes and the percentage of P4HA2-positive fibroblasts. Although we demonstrated a significant association between high P4HA2 expression in fibroblasts and the morphological presence of stromal changes, it seems unlikely that P4HA2 expression can be used as an alternative for the histopathological evaluation of the DCIS-associated stroma.

Prognostic and Predictive Value of HER2 Expression in Ductal Carcinoma In Situ: Results from the UK/ANZ DCIS Randomized Trial.

HER2 is overexpressed more frequently in ductal carcinoma in situ (DCIS) than in invasive breast cancer but its prognostic significance and predictive role for radiotherapy has not been clearly established. We investigated the prognostic and predictive value of HER2 overexpression in DCIS. HER2 expression was evaluated by IHC using the HercepTest™ in samples from UK/ANZ DCIS trial participants (n = 755) with IHC 3+ expression categorized as HER2 positive for primary analyses. Sensitivity analyses included HER2 categorization as negative (IHC 0,1+), equivocal (IHC 2+), and positive (IHC 3+) and analyses restricted to a nested case-control component where 181 cases (with recurrence) were matched to 362 controls by treatment arm and age. Two-hundred and forty-five (34.4%) of evaluable 713 samples [181 ipsilateral breast events (IBE)] were HER2 positive. HER2 overexpression was associated with significantly increased risk of IBE [HR = 2.29; 95% confidence interval (95% CI), 1.64-3.14; P < 0.0001] and in situ IBE (DCIS-IBE; HR = 2.90; 95% CI, 1.91-4.40; P < 0.0001), but not of invasive IBE (I-IBE; HR = 1.40; 95% CI, 0.81-2.42; P = 0.23; Pheterogeneity = 0.04). Inclusion of HER2 significantly improved [Δχ2 (1d.f.) 12.25; P = 0.0005] a prognostic model of clinicopathological and treatment variables, HER2 being an independent predictor of IBE (multivariate HR = 1.91; 95% CI, 1.33-2.76; P = 0.0004). Radiotherapy benefit in preventing DCIS-IBE was significantly greater (Pheterogeneity = 0.04) in HER2-positive DCIS (HR = 0.16; 95% CI, 0.07-0.41) compared with HER2-negative DCIS (HR = 0.58; 95% CI, 0.28-1.19). HER2 overexpression is associated with significantly increased risk of in situ recurrence and is also predictive of radiotherapy benefit, with greater reductions in in situ but not invasive recurrences in HER2-positive DCIS.

Prognostic Value of ER and PgR Expression and the Impact of Multi-clonal Expression for Recurrence in Ductal Carcinoma in situ: Results from the UK/ANZ DCIS Trial.

The prognostic value of estrogen receptor (ER)/progesterone receptor (PgR) expression in ductal carcinoma in situ (DCIS) is unclear. We observed multi-clonality when evaluating ER/PgR expression in the UK/ANZ DCIS trial, therefore, we investigated the prognostic role of both uni-clonal and multi-clonal ER/PgR expression in DCIS. Formalin-fixed paraffin embedded tissues were collected from UK/ANZ DCIS trial participants (n = 755), and ER/PgR expression was evaluated by IHC in 181 cases (with recurrence) matched to 362 controls by treatment arm and age. Assays were scored by the Allred method and by a newly devised clonal method-analyses categorizing multi-clonal DCIS as ER/PgR-positive as per current practice (Standard) and as ER/PgR-negative (clonal) were performed. ER expression was multi-clonal in 11% (39/356) of ER-positive (70.6%, 356/504) patients. Ipsilateral breast event (IBE) risk was similarly higher in ER-multi-clonal and ER-negative DCIS as compared with DCIS with uni-clonal ER expression. ER-negative DCIS (clonal) had a higher risk of in situ IBE [OR 4.99; 95% confidence interval (CI), 2.66-9.36; P < 0.0001], but the risk of invasive IBE was not significantly higher (OR 1.72; 95% CI, 0.84-3.53; P = 0.14), P heterogeneity = 0.03. ER was an independent predictor in multivariate analyses (OR 2.66; 95% CI, 1.53-4.61). PgR status did not add to the prognostic information provided by ER. ER expression is a strong predictor of ipsilateral recurrence risk in DCIS. ER-positive DCIS with distinct ER-negative clones has a recurrence risk similar to ER-negative DCIS. ER should be routinely assessed in DCIS, and ER scoring should take clonality of expression into account.

High EZH2 expression in ductal carcinoma in situ diagnosed on breast core needle biopsy is an independent predictive factor for upgrade on surgical excision

PurposeApproximately 25 % of DCIS diagnosed on breast core needle biopsy (CNB) is upgraded to invasive carcinoma on surgical excision. Risk factors to predict the upgrade on excision are not well established, leading many patients to be over or under-treated. EZH2 was shown to be associated with aggressive behavior of cancer from many sites, including breast cancer. We aimed to analyze EZH2 expression and tumor infiltrating lymphocytes (TILs) in DCIS as predictive factors for an upgrade on excision. MethodsWe assessed EZH2 expression in 34 DCIS cases diagnosed on CNB and upgraded to invasive carcinoma on excision. Then, we compared these cases with 60 control cases that were not upgraded on excision. A staining score for DCIS (0–12) was obtained by multiplying the staining intensity (0–3) and the percentage of positive cells (1–4). The nuclear staining score ≥6 was considered as ‘high’ expression. Results46 of 94 (49 %) DCIS on CNB showed high EZH2 expression. EZH2 expression was directly correlated with TILs density, nuclear grade, HER2 expression, Ki-67 index and negative ER status. On univariate analysis, upgrade on excision was associated with high EZH2 expression, high TILs density, negative ER status and high Ki-67 index. Multivariate analysis revealed the high EZH2 expression as the only independent predictive factor for upgrade on excision. ConclusionsOur study revealed the high EZH2 expression as the only independent predictive factor for an upgrade on excision. Future studies should focus on the evaluation of EZH2 expression in tumor-microenvironment interaction in terms of diagnostic, treatment and prognostic purposes.

The clinical significance of oestrogen receptor expression in breast ductal carcinoma in situ

BackgroundOestrogen receptor (ER) in invasive breast cancer (BC) predicts response to endocrine therapy (ET) and provides prognostic value. In this study, we investigated the value of ER expression in ductal carcinoma in situ (DCIS) in terms of outcome and the impact on ET decision.MethodsIn total, 643 pure DCIS, diagnosed at Nottingham University Hospitals, were assessed for ER. Clinicopathological data were correlated against ER status, together with assessment of recurrence rate.ResultsER positivity was observed in 74% (475/643) of cases. ER positivity was associated with clinicopathological variables of good prognosis; however, outcome analysis revealed that ER status was not associated with local recurrence. In the intermediate- and high-grade ER-positive DCIS, 58% (11/19) and 63% (15/24) of the recurrences were invasive, respectively, comprising 7% and 6% of all ER-positive DCIS, respectively. Invasive recurrence in low-grade DCIS was infrequent (2%), and none of these patients died of BC. The ER status of the recurrent invasive tumours matched the primary DCIS ER status (94% in ipsilateral and 90% of contralateral recurrence).ConclusionThe strong correlation between DCIS and invasive recurrence ER status and the clinical impact of ET justify discussion of the use of ET in ER-positive DCIS treated by breast-conserving surgery. The excellent outcome of low-grade DCIS, which was almost always ER-positive, does not, in the opinion of authors, justify the use of risk-reducing ET. Therefore, the decision on ET for DCIS should be personalised and consider grade, ER status and other characteristics.

BCL2 expression in ductal carcinoma of breast and its association with other clinicopathologic variables

Breast cancer has now become the most common cancer among Indian females exceeding cervical cancer. Age adjusted incidence rate as high as 25.8 per 100,000 women and mortality 12.7 per 100,000 women. Trends of breast cancer now in India are increasing incidence at younger age group, late stage of presentation, aggressive cancers in the young. Bcl 2-a protooncogene identified in 1984. The protein is found mainly in the periphery of mitochondria, on the perinuclear membrane, and in the endoplasmic reticulum. In our study bcl2 expression in different histologic types of breast carcinoma and correlates we read about its expression with other clinico pathologic variables such as tumour size, histological grade, lymph node status, hormone receptor status and Nottingham prognostic index. :In this study 23.3% (7 out of 30) of the cases showed positivity for bcl2 expression of which all cases were strongly positive. Bcl2 expression was found in 45.5% grade I well differentiated ductal carcinoma,14.3% of Grade II Moderately differentiated ductal carcinomas, all cases of mucinous carcinoma of breast(p-&amp;#60;0.025) Bcl2 and ER/PR status found to have a statistically significant direct correlation with p value&amp;#60;0.004. Hence Bcl2 antagonism in these ER+ tumors might increase the effectiveness of these predominately proapoptotic treatment even more than it does from combination with endocrine therapies. Further development of bcl2 inhibitors has been explored and small molecule inhibitors such as ABT-737 AND ABT-199 have been recently introduced. Emerging evidence also suggests the usefulness of this type of theraphy in breast cancer.

Abstract P3-02-12: CAV1, MCT1, and MCT4 expression in ductal carcinoma in situ of the breast and its association with clinicopathologic features

Abstract Background: Multicompartment tumor metabolism and metabolic coupling are markers of aggressive tumor behavior, clinically manifested as disease recurrence and progression. Loss of caveolin-1(CAV1) in stromal cells and upregulation of monocarboxylate transporters (MCTs), especially MCT1 and MCT4, in both stromal and cancer cells have been identified as playing an important role in the metabolic coupling necessary for release and uptake of metabolites. However, this phenomenon has only scarcely been described in ductal carcinoma in situ (DCIS) of the breast. The purpose of this study was to investigate the role of CAV1, MCT1, and MCT4 in DCIS carcinogenesis and its association with clinicopathologic factors. Materials and methods: CAV1, MCT1, and MCT4 expression was examined in 9 pairs of DCIS tissues and matched normal adjacent tissues at mRNA and protein levels by qRT-PCR, RNAscope in situ hybridization (ISH) and immunohistochemistry. Immunohistochemical staining of CAV1, MCT1, and MCT4 was done in 79 DCIS samples with known hormone receptor (HR) and human epidermal growth factor 2 (HER2) expression using tissue microarray. Results: CAV1 mRNA expression by qRT-PCR analysis was significantly decreased in DCIS tissues compared to their corresponding normal tissues. On the other hand, MCT1 and MCT4 mRNA expression in DCIS tissues were increased compared with corresponding normal tissues and the difference was statistically significant in MCT1. Compared with their corresponding normal tissues, DCIS tissues showed decreased stromal CAV1 mRNA and protein expression and increased epithelial MCT1 and MCT4 mRNA and protein expression by ISH and immunohistochemistry. Low stromal CAV1, high epithelial MCT1, and high epithelial MCT4 expressions were observed in 29 (36.7%), 51 (64.6%) and 15 (18.9%) cases with DCIS, respectively. Low stromal CAV1 expression was significantly associated with high nuclear grade (P &amp;lt; 0.05). High epithelial MCT4 expression was associated with larger tumor size and HER2 positivity (P &amp;lt; 0.05 and P &amp;lt; 0.05, respectively). Although not statistically significant, low stromal CAV1 and high epithelial MCT4 expression tended to be associated with recurrence of DCIS. No associations were observed between stromal CAV1 expression and epithelial MCT 1 or MCT4 expression. Conclusions: These results suggested that changes in CAV1, MCT1, and MCT4 are associated with carcinogenesis of DCIS, and further studies are needed for their clinical usefulness. Keywords: Ductal carcinoma in situ; CAV1; MCT1; MCT4; Metabolism Citation Format: Ji Shin Lee, Nah Ihm Kim, Min Ho Park. CAV1, MCT1, and MCT4 expression in ductal carcinoma in situ of the breast and its association with clinicopathologic features [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-02-12.

Associations of B7-H3 and B7-H4 Expression in Ductal Carcinoma In Situ of the Breast With Clinicopathologic Features and T-Cell Infiltration.

B7-H3 and B7-H4 play an inhibitory role in T-cell function by limiting proliferation and cytokine production. Information about B7-H3 and B7-H4 expression in ductal carcinoma in situ (DCIS) remains uncertain. The objective of this study was to evaluate the expression levels of B7-H3 and B7-H4 in DCIS and their associations with clinicopathologic features and T-cell infiltration. B7-H3 and B7-H4 mRNA and protein expression levels in 8 pairs of DCIS tissues and matched normal adjacent tissues were examined by RNAscope in situ hybridization and immunohistochemistry analysis. Immunohistochemical staining of B7-H3, B7-H4, CD3, and CD8 was performed for 79 DCIS samples using tissue microarray. RNAscope in situ hybridization and immunohistochemistry analysis revealed that expression levels of B7-H3 and B7-H4 in DCIS tissues were higher than those in corresponding normal tissues. B7-H3 and B7-H4 mRNA and protein appeared to be mainly expressed in DCIS carcinoma cells. High B7-H3 and B7-H4 expression was observed in 58 (73.4%) and 62 (78.5%) cases with DCIS, respectively. High B7-H3 expression was significantly associated with high-nuclear grade and presence of comedo-type necrosis (both P<0.05). B7-H3 expression in HR/HER2 subtype was higher than that in HR/HER2 subtype (P<0.05). B7-H3 and B7-H4 expression levels were negatively related to the density of CD3 and CD8 T-cell infiltrates. B7-H3 and B7-H4 may play an important role in immune surveillance mechanisms of DCIS. They might be useful targets to develop immune-based therapy to alter or prevent DCIS progression.

OLFM4 Expression in Ductal Carcinoma In Situ and in Invasive Breast Cancer Cohorts by a SWATH-Based Proteomic Approach.

Human olfactomedin-4 (OLFM4) is a secreted protein involved in a variety of cellular functions including proliferation, differentiation, apoptosis, and cell adhesion. OLFM4 expression has been studied in several tumor types including gastric, colorectal, lung, and endometrioid cancers where it has been suggested to be an independent favorable or unfavorable prognostic marker. For breast cancer, the clinical significance of OLFM4 is still unclear. In the present study, SWATH-MS is used as a tool for the robust identification and quantification of breast tissue proteins. SWATH-MS data show that OLFM4 expression is higher in DCIS than in invasive breast cancer. In-depth analysis of the breast tumor proteome show that OLFM4 is a favorable pronostic marker. Serum OLFM4 levels in peripheral blood are also analyzed by ELISA in 825 cases, including 94 cases of healthy individuals, 61 cases of non-invasive breast tumor (DCIS) and 670 cases of breast cancer (BC). It is found that serum OLFM4 levels are significantly higher in the DCIS cohort and in the breast cancer cohort compared with the healthy controls. This result suggests that circulating OLFM4 could be an interesting biomarker of early breast cancer. Data are available via ProteomeXchange with identifier PXD014194.

APOBEC3B Gene Expression in Ductal Carcinoma In Situ and Synchronous Invasive Breast Cancer.

The underlying mechanism of the progression of ductal carcinoma in situ (DCIS), a non-obligate precursor of invasive breast cancer (IBC), has yet to be elucidated. In IBC, Apolipoprotein B mRNA Editing Enzyme, Catalytic Polypeptide-Like 3B (APOBEC3B) is upregulated in a substantial proportion of cases and is associated with higher mutational load and poor prognosis. However, APOBEC3B expression has never been studied in DCIS. We performed mRNA expression analysis of APOBEC3B in synchronous DCIS and IBC and surrounding normal cells. RNA was obtained from 53 patients. The tumors were categorized based on estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (Her2) and phosphoinositide-3-kinase, catalytic, alpha polypeptide (PIK3CA) mutation status. APOBEC3B mRNA levels were measured by RT-qPCR. The expression levels of paired DCIS and adjacent IBC were compared, including subgroup analyses. The normal cells expressed the lowest levels of APOBEC3B. No differences in expression were found between DCIS and IBC. Subgroup analysis showed that APOBEC3B was the highest in the ER subgroups of DCIS and IBC. While there was no difference in APOBEC3B between wild-type versus mutated PIK3CA DCIS, APOBEC3B was higher in wild-type versus PIK3CA-mutated IBC. In summary, our data show that APOBEC3B is already upregulated in DCIS. This suggests that APOBEC3B could already play a role in early carcinogenesis. Since APOBEC3B is a gain-of-function mutagenic enzyme, patients could benefit from the therapeutic targeting of APOBEC3B in the early non-invasive stage of breast cancer.

Abstract 1451: HER2 peptide pulsed dendritic cell vaccine induce senescence and eliminates disseminated cancer cells in a preventive model of transgenic HER2/neu breast cancer

Abstract HER-2/neu overexpression plays a critical role in breast cancer development, and its expression in ductal carcinoma in situ (DCIS) is associated with development of invasive breast cancer. The detection of disseminated cancer cells (DCCs) in early-stage DCIS likely to become invasive and manifests prominent role in metastasis and recurrence. The HER2-positive DCCs can easily escape targeted therapies and become a source of tumor recurrence suggesting that targeting these cells may provide eminent benefits in HER2 positive breast cancer patients. Unfortunately, the conventional therapies that target these DCCs are limited. Previous studies from our lab have shown that HER2 peptide pulsed-DC1 (HER2-DC1) vaccine induced 30% complete response (pCR) in DCIS patients. However, little is known about the effect of HER2-DC1 vaccine on DCCs. Here, we investigated the efficacy of HER2-DC1 vaccine on DCCs in a transgenic HER2 mammary cancer model (neuT). The key features of this model are each one of ten mammary glands develops an independent carcinoma that slowly progresses from a microscopic lesion to an invasive tumor and metastasis is mainly driven by DCCs. Since this model mimics some of the most critical features of human disease, we evaluated the efficacy of HER2-DC1 vaccine on DCCs. Mice received six doses of HER2-DC1 vaccine subcutaneously twice a week. The spontaneous tumor development in the mammary glands of NeuT mice was examined once a week by ultrasound until the age of week 16. HER2-DC1 vaccine significantly prevented spontaneous tumor growth in NeuT mice. Remarkably, HER2-DC1 vaccine treatment significantly decreased HER2+CYT8/18+Ki-67+ proliferative DCCs (2%, p&amp;lt;0.002) in the bone marrow (BM-DCCs) compared to untreated mice (6%) by flow cytometry. We also observed increased senescent DCCs (82%, p&amp;lt;0.0001 compared to untreated mice, 37%) by a β-gal assay. BM-DCCs in HER2-DC1 vaccinated mice had reduced expression of Ki-67 compared to untreated mice. Multicolor flow cytometry demonstrated elevated levels of CD4 T cells (2 fold increase) and CD8 T cells (1 fold increase) in the bone marrow after HER2-DC1 vaccination compared to untreated mice. Importantly, accumulation of CD4 T cells (5 fold increase), CD8 T cells (19 fold increase) and B cells (100 fold increase) was observed in the mammary glands of HER2-DC1 vaccinated mice with strong anti-HER2 Th1 immune responses. Notably, HER2-DC1 vaccine led to an increased in the M1 macrophage phenotype (3 fold increase) and decreased M2 type (8 fold decrease) at the tumor site. Treatment of DCCs with Th1 cytokines, IFN-γ or TNF-α significantly induced senescence (76.3%, p&amp;lt;0.0001) in cultured DCCs compared to untreated cells (26%) in vitro. These results describe the novel role of HER2-DC1 vaccine in targeting DCCs and a possible role in prevention of metastasis and recurrence. Citation Format: Ganesan Ramamoorthi, Krithika Kodumudi, Colin Synder, William Dominguez-Viqueira, Scott Kidd, Shari Pilon-Thomas, Brian Czerniecki. HER2 peptide pulsed dendritic cell vaccine induce senescence and eliminates disseminated cancer cells in a preventive model of transgenic HER2/neu breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1451.

Abstract P4-06-25: B7-H3 and B7-H4 expression in ductal carcinoma in situ of the breast: Associations with clinicopathologic features and T-cell infiltration

Abstract Background: With the clinical success of immune check point blockades in treating malignant tumors, there are intense investigations in identifying new pathways to activate immune system by targeting immunoregulatory molecules. B7-H3 and B7-H4 play an inhibitory role in T cell function by limiting proliferation and cytokine production. Although several studies have investigated the expression of B7-H3 and B7-H4 in invasive breast cancers, the information of the B7-H3 and B7-H4 molecules in ductal carcinoma in situ (DCIS) remains uncertain. The present work was undertaken to evaluate the expression of B7-H3 and B7-H4 in DCIS and its association with clinicopathological features in patients with DCIS. In addition, the association of B7-H3 and B7-H4 expression with the T-cell infiltration was also assessed to investigate its roles in the regulation of tumor immune surveillance. Materials and methods: B7-H3 and B7-H4 expression was examined in 8 pairs of DCIS tissues and matched normal adjacent tissues at mRNA and protein levels by RNAscope in situ hybridization (ISH) and immunohistochemistry. Immunohistochemical staining of B7-H3 and B7-H4 was done in 79 DCIS samples with known hormone receptor (HR) and human epidermal growth factor 2 (HER2) expression using tissue microarray. In addition, immunohistochemical staining was also performed for the T cell lineage markers CD3 and CD8 in DCIS. Results: RNAscope ISH and immunohistochemistry of B7-H3 and B7-H4 confirmed their increases in DCIS tissues compared with their corresponding normal tissues. B7-H3 and B7-H4 mRNA and protein expression appeared to be concentrated mainly in the DCIS carcinoma cells. High B7-H3 and B7-H4 expression was observed in 58 (73.4%) and 62 (78.5%) cases with DCIS, respectively. High B7-H3 expression was significantly associated with high nuclear grade and presence of comedo-type necrosis (P &amp;lt; 0.05 and P &amp;lt; 0.05, respectively). B7-H3 expression was higher in the HR–/HER2+ subtypes than in the HR+/HER2– subtype (P &amp;lt; 0.05). B7-H3 and B7-H4 expression tended to be associated with low stromal tumor infiltrating lymphocytes density and was negatively related to the CD3+ and CD8+ T cell infiltrates density. Conclusions: These results suggest that B7-H3 and B7-H4 may play an important role in immune surveillance mechanisms of DCIS and may be useful targets for immune-based therapy to alter or prevent DCIS progression. Citation Format: Lee JS, Kim G-E, Park MH, Yoon JH. B7-H3 and B7-H4 expression in ductal carcinoma in situ of the breast: Associations with clinicopathologic features and T-cell infiltration [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-06-25.

B7-H3 and B7-H4 expression in ductal carcinoma in situ of the breast detected with RNA in situ hybridization and immunohistochemistry and its association with clinicopathologic features and T-cell infiltration

Background: With the clinical success of immune check point blockades in treating malignant tumors, there are intense investigations in identifying new pathways to activate immune system by targeting immunoregulatory molecules. B7-H3 and B7-H4 play an inhibitory role in T cell function by limiting proliferation and cytokine production. Although several studies have investigated the expression of B7-H3 and B7-H4 in invasive breast cancers, the information of the B7-H3 and B7-H4 molecules in ductal carcinoma in situ (DCIS) remains uncertain. We investigated the expression of B7-H3 and B7-H4 in DCIS and determined its association with tumor infiltrating T-lymphocytes and major clinicopathological features in DCIS

Abstract 625: Cytotoxic T lymphocyte antigen 4 (CTLA-4) expression in ductal carcinoma in situ (DCIS) of the breast

Abstract Background: Ductal carcinoma in situ (DCIS) consists of a heterogeneous group that can be subclassified by molecular signatures. High grade DCIS is commonly associated with periductal inflammation, a feature associated with increased risk for microinvasion. We previously assessed the immune microenvironment of DCIS and reported that HER2+ DCIS has increased numbers of tumor infiltrating lymphocytes (TILs), with significant expression of PD-L1. CTLA-4 is a supplementary immunomodulatory marker, which serves as a negative regulator of T-cell response. Targeted therapy is currently available against both PD-L1 and CTLA-4, and studies suggest an enhanced response with combination therapy as these therapies act though different mechanisms. In this study we evaluated the expression of CTLA-4 in both TILs and tumor cells in DCIS. Design: The study population consisted of 74 cases of DCIS treated with surgical excision from 2008-2012. The molecular subtypes of DCIS were determined based on ER and HER2 expression. Tissue microarrays were constructed (3 cores/case) to account for tumor heterogeneity. The TMAs were immunostained for CTLA-4 and the expression CTLA-4 was assessed. Results: Of the 74 cases, 41 were classified as Luminal A (ER+/HER2-), 17 as Luminal B (4 as Luminal B HER2- [ER+/HER2-/high Ki-67] and 13 as Luminal B HER2+ [ER+/HER2+]), 11 as HER2+ (ER-/HER2+) and 5 as basal (ER-/HER2-). Overall, the DCIS tumor cells expressed CTLA-4 in 58% of Luminal B (HER2+ 53% [7/13]; HER2- 75% [3/4]) and 36% of HER2+ (4/11), while only 39% of Luminal A (16/41), and one basal DCIS (1/5) did. In addition, the presence of CTLA-4 positive TILs was strongly associated with HER2+ expression (Luminal B HER2+=21.8%, HER2+=13.4%), compared to HER2- DCIS (Luminal B HER2-=8.5%, Luminal A=7.3%, Basal=6.4%) (p=0.026). Conclusion: 1. CTLA-4 expression in TILs is increased in HER2+ DCIS. 2. A significant percent of tumor cells express CTLA-4 in all DCIS subtypes. Our results further advance our understanding of the role of the immune microenvironment in DCIS. Additional studies are needed to further elucidate the complex interplay between the host immune system and DCIS, which may offer insights into breast carcinoma progression and possible use of novel immune-based therapies. Citation Format: Jorge E. Novo, Lauren Rosen, Julianne M. Ubago, Jennifer Pincus, Luis Blanco, Kalliopi P. Siziopikou. Cytotoxic T lymphocyte antigen 4 (CTLA-4) expression in ductal carcinoma in situ (DCIS) of the breast [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 625.

Differential Gene Expression in Ductal Carcinoma In Situ of the Breast Based on ERBB2 Status.

The molecular signature of ductal carcinoma in situ (DCIS) in the breast is not well understood. Erb-b2 receptor tyrosine kinase 2 (ERBB2 [formerly known as HER2/neu]) positivity in DCIS is predictive of coexistent early invasive breast carcinoma. The aim of this study is to identify the gene-expression signature profiles of estrogen receptor (ER)/progesterone receptor (PR)-positive, ERBB2, and triple-negative subtypes of DCIS. Based on ER, PR, and ERBB2 status, a total of 18 high nuclear grade DCIS cases with no evidence of invasive breast carcinoma were selected along with 6 non-neoplastic controls. The 3 study groups were defined as ER/PR-positive, ERBB2, and triple-negative subtypes. A total of 49 genes were differentially expressed in the ERBB2 subtype compared with the ER/PR-positive and triple-negative groups. PROM1 was overexpressed in the ERBB2 subtype compared with ER/PR-positive and triple-negative subtypes. Other genes differentially expressed included TAOK1, AREG, AGR3, PEG10, and MMP9. Our study identified unique gene signatures in ERBB2-positive DCIS, which may be associated with the development of invasive breast carcinoma. The results may enhance our understanding of the progression of breast cancer and become the basis for developing new predictive biomarkers and therapeutic targets for DCIS.

DUCTAL CARCINOMA IN SITU AND INVASIVE BREAST CANCER-BASED DIFFERENTIAL GENE EXPRESSION STUDY FOR THERAPEUTIC DEVELOPMENT

ABSTRACTObjective: Breast cancer is the second most common cancer in women globally. Multiple inherited mutations in genes are predominantly associatedwith breast cancer. The gene expression profiling of breast tumors generated by DNA microarray analysis provides molecular phenotyping thatdetermines and characterizes the classifications of these tumors.Methods: In this work, we used gene expression profiling of breast cancer samples from Gene Expression Omnibus (GEO) database. The datasetGSE41194, retrieved from GEO, was used to investigate differential gene expression in ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC).The dataset contains 26 DCIS and 24 IBC samples. The data were analyzed in R and Bioconductor. To normalize the data Robust Multiarray Average(RMA) method was applied, limma software was used to identify the differentially expressed genes (DEGs) in DCIS and IBC; an adjusted p value ≤0.05was used to filter differentially expressed probe sets, and a fold change (FC) ≥ 2 to identify upregulated and ≤−2 for downregulated genes. The DEGsretrieved were clustered and annotated using Database for Annotation, Visualization and Integrated Discovery (DAVID) Bioinformatics Resourceswith an EASE score ≤0.1 and count 2.Results: The analysis obtained 72 DEGs with a p≤0.05. The FC≥2 identified 38 upregulated probesets and FC≤−2 identified 34 downregulated probesets. The up and downregulated genes obtained in various comparisons were characterized based on gene ontology (GO) and pathway analyses inDAVID, which retrieved six genes that had principal pathways targeting breast cancer.Conclusion: Identification of these genes and pathways enhances the knowledge and progression of DCIS to IBC; paving a novel way for developingnew therapies for treating patients with breast cancer.Keywords: Molecular phenotyping, Gene Expression, Ductal carcinoma in situ, Invasive breast cancer.