Perturbed myoepithelial cell differentiation in BRCA mutation carriers and in ductal carcinoma in situ.

Myoepithelial cells play key roles in normal mammary gland development and in limiting pre-invasive to invasive breast tumor progression, yet their differentiation and perturbation in ductal carcinoma in situ (DCIS) are poorly understood. Here, we investigated myoepithelial cells in normal breast tissues of BRCA1 and BRCA2 germline mutation carriers and in non-carrier controls, and in sporadic DCIS. We found that in the normal breast of non-carriers, myoepithelial cells frequently co-express the p63 and TCF7 transcription factors and that p63 and TCF7 show overlapping chromatin peaks associated with differentiated myoepithelium-specific genes. In contrast, in normal breast tissues of BRCA1 mutation carriers the frequency of p63+TCF7+ myoepithelial cells is significantly decreased and p63 and TCF7 chromatin peaks do not overlap. These myoepithelial perturbations in normal breast tissues of BRCA1 germline mutation carriers may play a role in their higher risk of breast cancer. The fraction of p63+TCF7+ myoepithelial cells is also significantly decreased in DCIS, which may be associated with invasive progression.

Comparison of residual cancer burden, American Joint Committee on Cancer staging and pathologic complete response in breast cancer after neoadjuvant chemotherapy: results from the I-SPY 1 TRIAL (CALGB 150007/150012; ACRIN 6657).

PURPOSE: Several pathologic staging systems characterize residual tumor in patients undergoing neoadjuvant chemotherapy for breast cancer. Pathologic complete response (pCR) is now accepted by the Food and Drug Administration as an endpoint for granting accelerated drug approval. Two other systems of post-neoadjuvant pathologic tumor staging-residual cancer burden (RCB) and the American Joint Committee on Cancer post-neoadjuvant therapy staging system (yAJCC)-have been developed to characterize residual tumors when patients do not achieve pCR. The optimal system and the ways in which these systems complement each other have not been fully determined. METHODS: Using data from the I-SPY 1 TRIAL, we compared pCR, RCB, and yAJCC as predictors of early recurrence-free survival (RFS) to identify ways to improve post-neoadjuvant pathologic evaluation. RESULTS: Among 162 patients assessed, pCR identified patients at lowest risk of recurrence, while RCB and yAJCC identified patients at highest risk. Hormone-receptor (HR) and HER2 subtypes further improved risk prediction. Recursive partitioning indicated that triple-negative or HER2+ patients with yAJCC III or RCB 3 have the highest recurrence risk, with an RFS of 27%. Our analysis also highlighted discrepancies between RCB and yAJCC stratification: 31% of patients had discrepant RCB and yAJCC scores. We identified differential treatment of lymph node involvement and tumor cellularity as drivers of these discrepancies. CONCLUSIONS: These data indicate that there is benefit to reporting both RCB and yAJCC for patients in order to identify those at highest risk of relapse.

DCLK1 is correlated with MET and ERK5 expression, and associated with prognosis in malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) is an aggressive cancer for which more effective treatments are needed. In this study, strong to moderate staining of MET and ERK5 was detected in 67.1 and 48% of the analyzed 73 human mesothelioma tumors, and significant correlation of MET and ERK5 expression was identified (P<0.05). We evaluated the doublecortin-like kinase 1 (DCLK1) expression in human mesothelioma tumors. Our results showed that 50.7% of the immunohistochemistry analyzed human mesothelioma tumors have strong to moderate staining of DCLK1, and its expression is significantly correlated with MET or ERK5 expression (P<0.05). Also, the upregulation of DCLK1 is correlated with poor prognosis in MPM patients (P=0.0235). To investigate whether DCLK1 is downstream of MET/ERK5 signaling in human mesothelioma, the effect of DCLK1 expression was analyzed after treatments with either the MET inhibitor XL184 or the ERK5 inhibitor XMD8-92 in human mesothelioma cell lines. Our results showed that the MET inhibitor XL184 reduced the expression of phospho­ERK5 and DCLK1 expression in human mesothelioma cell lines. In addition, the ERK5 inhibitor XMD8-92 reduced the expression of phospho-ERK5 and DCLK1 expression in human mesothelioma cell lines. Furthermore, XML184 and XMD8-92 treatment impaired invasion and tumor sphere formation ability of H290 mesothelioma cells. These results suggest that DCLK1 is regulated by MET/ERK5 signaling in human mesothelioma, and the MET/ERK5/DCLK1 signaling cascade could be further developed into a promising therapeutic target against mesothelioma.

Characterizing the immune microenvironment in high-risk ductal carcinoma in situ of the breast.

PURPOSE: The recent increase in the incidence of ductal carcinoma in situ (DCIS) has sparked debate over the classification and treatment of this disease. Although DCIS is considered a precursor lesion to invasive breast cancer, some DCIS may have more or less risk than is realized. In this study, we characterized the immune microenvironment in DCIS to determine if immune infiltrates are predictive of recurrence. METHODS: Fifty-two cases of high-grade DCIS (HG-DCIS), enriched for large lesions and a history of recurrence, were age matched with 65 cases of non-high-grade DCIS (nHG-DCIS). Immune infiltrates were characterized by single- or dual-color staining of FFPE sections for the following antigens: CD4, CD8, CD20, FoxP3, CD68, CD115, Mac387, MRC1, HLA-DR, and PCNA. Nuance multispectral imaging software was used for image acquisition. Protocols for automated image analysis were developed using CellProfiler. Immune cell populations associated with risk of recurrence were identified using classification and regression tree analysis. RESULTS: HG-DCIS had significantly higher percentages of FoxP3+ cells, CD68+ and CD68+PCNA+ macrophages, HLA-DR+ cells, CD4+ T cells, CD20+ B cells, and total tumor infiltrating lymphocytes compared to nHG-DCIS. A classification tree, generated from 16 immune cell populations and 8 clinical parameters, identified three immune cell populations associated with risk of recurrence: CD8+HLADR+ T cells, CD8+HLADR- T cells, and CD115+ cells. CONCLUSION: These findings suggest that the tumor immune microenvironment is an important factor in identifying DCIS cases with the highest risk for recurrence and that manipulating the immune microenvironment may be an efficacious strategy to alter or prevent disease progression.

Analysis of lung tumor initiation and progression in transgenic mice for Cre-inducible overexpression of Cul4A gene.

BACKGROUND: Lung cancer is the leading cause of morbidity and death worldwide. Although the available lung cancer animal models have been informative and further propel our understanding of human lung cancer, they still do not fully recapitulate the complexities of human lung cancer. The pathogenesis of lung cancer remains highly elusive because of its aggressive biologic nature and considerable heterogeneity, compared to other cancers. The association of Cul4A amplification with aggressive tumor growth and poor prognosis has been suggested. Our previous study suggested that Cul4A is oncogenic in vitro, but its oncogenic role in vivo has not been studied. METHODS: Viral delivery approaches have been used extensively to model cancer in mouse models. In our experiments, we used Cre-recombinase induced overexpression of the Cul4A gene in transgenic mice to study the role of Cul4A on lung tumor initiation and progression and have developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A. RESULTS: Here we show that the use of a recombinant adenovirus expressing Cre-recombinase ("AdenoCre") to induce Cul4A overexpression in the lungs of mice allows controls of the timing and multiplicity of tumor initiation. Following our mouse models, we are able to study the potential role of Cul4A in the development and progression in pulmonary adenocarcinoma as well. CONCLUSION: Our findings indicate that Cul4A is oncogenic in vivo, and this mouse model is a tool in understanding the mechanisms of Cul4A in human cancers and for testing experimental therapies targeting Cul4A.

Cul4A overexpression associated with Gli1 expression in malignant pleural mesothelioma.

Malignant pleural mesothelioma (mesothelioma) is a highly aggressive cancer without an effective treatment. Cul4A, a scaffold protein that recruits substrates for degradation, is amplified in several human cancers, including mesothelioma. We have recently shown that Cul4A plays an oncogenic role in vitro and in a mouse model. In this study, we analysed clinical mesothelioma tumours and found moderate to strong expression of Cul4A in 70.9% (51/72) of these tumours, as shown by immunohistochemistry. In 72.2% mesothelioma tumours with increased Cul4A copy number identified by fluorescence in situ hybridization analysis, Cul4A protein expression was moderate to strong. Similarly, Cul4A was overexpressed and Cul4A copy number was increased in human mesothelioma cell lines. Because Gli1 is highly expressed in human mesothelioma cells, we compared Cul4A and Gli1 expression in mesothelioma tumours and found their expression associated (P < 0.05, chi-square). In mesothelioma cell lines, inhibiting Cul4A by siRNA decreased Gli1 expression, suggesting that Gli1 expression is, at least in part, regulated by Cul4A in mesothelioma cells. Our results suggest a linkage between Cul4A and Gli1 expression in human mesothelioma.

PR-Set7 is Degraded in a Conditional Cul4A Transgenic Mouse Model of Lung Cancer.

BACKGROUND: Maintenance of genomic integrity is essential to ensure normal organismal development and to prevent diseases such as cancer. PR-Set7 (also known as Set8) is a cell cycle regulated enzyme that catalyses monomethylation of histone 4 at Lys20 (H4K20me1) to promote chromosome condensation and prevent DNA damage. Recent studies show that CRL4CDT2-mediated ubiquitylation of PR-Set7 leads to its degradation during S phase and after DNA damage. This might occur to ensure appropriate changes in chromosome structure during the cell cycle or to preserve genome integrity after DNA damage. METHODS: We developed a new model of lung tumor development in mice harboring a conditionally expressed allele of Cul4A. We have therefore used a mouse model to demonstrate for the first time that Cul4A is oncogenic in vivo. With this model, staining of PR-Set7 in the preneoplastic and tumor lesions in AdenoCre-induced mouse lungs was performed. Meanwhile we identified higher protein level changes of γ-tubulin and pericentrin by IHC. RESULTS: The level of PR-Set7 down-regulated in the preneoplastic and adenocarcinomous lesions following over-expression of Cul4A. We also identified higher levels of the proteins pericentrin and γ-tubulin in Cul4A mouse lungs induced by AdenoCre. CONCLUSIONS: PR-Set7 is a direct target of Cul4A for degradation and involved in the formation of lung tumors in the conditional Cul4A transgenic mouse model.

Serial expression analysis of breast tumors during neoadjuvant chemotherapy reveals changes in cell cycle and immune pathways associated with recurrence and response.

INTRODUCTION: The molecular biology involving neoadjuvant chemotherapy (NAC) response is poorly understood. To elucidate the impact of NAC on the breast cancer transcriptome and its association with clinical outcome, we analyzed gene expression data derived from serial tumor samples of patients with breast cancer who received NAC in the I-SPY 1 TRIAL. METHODS: Expression data were collected before treatment (T1), 24-96 hours after initiation of chemotherapy (T2) and at surgery (TS). Expression levels between T1 and T2 (T1 vs. T2; n = 36) and between T1 and TS (T1 vs. TS; n = 39) were compared. Subtype was assigned using the PAM50 gene signature. Differences in early gene expression changes (T2 - T1) between responders and nonresponders, as defined by residual cancer burden, were evaluated. Cox proportional hazards modeling was used to identify genes in residual tumors associated with recurrence-free survival (RFS). Pathway analysis was performed with Ingenuity software. RESULTS: When we compared expression profiles at T1 vs. T2 and at T1 vs. TS, we detected significantly altered expression of 150 and 59 transcripts, respectively. We observed notable downregulation of proliferation and immune-related genes at T2. Lower concordance in subtype assignment was observed between T1 and TS (62 %) than between T1 and T2 (75 %). Analysis of early gene expression changes (T2 - T1) revealed that decreased expression of cell cycle inhibitors was associated with poor response. Increased interferon signaling (TS - T1) and high expression of cell proliferation genes in residual tumors (TS) were associated with reduced RFS. CONCLUSIONS: Serial gene expression analysis revealed candidate immune and proliferation pathways associated with response and recurrence. Larger studies incorporating the approach described here are warranted to identify predictive and prognostic biomarkers in the NAC setting for specific targeted therapies. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00033397 . Registered 9 Apr 2002.

CK2α, over-expressed in human malignant pleural mesothelioma, regulates the Hedgehog signaling pathway in mesothelioma cells.

BACKGROUND: The Hedgehog (Hh) signaling pathway has been implicated in stem cell maintenance and its activation is aberrant in several types of cancer including mesothelioma. Protein kinase CK2 affects several cell signaling pathways through the mechanism of phosphorylation. METHODS: Protein and mRNA levels of CK2α and Gli1 were tested by quantitative RT-PCR and immunohistochemistry staining in mesothelioma samples and cell lines. Down-regulated Gli1 expression and transcriptional activity were demonstrated by RT-PCR, Western blot and luciferase reporter assay. RESULTS: In this study, we show that CK2α is over-expressed and a positive regulator of Hegdehog/Gli1 signaling in human malignant pleural mesothelioma. First of all, we found that the mRNA levels of CK2α and Gli1 were broadly elevated and correlated (n = 52, r = 0.401, P < 0.05), compared with LP9 (a normal mesothelial cell line). We then investigated their expression at the protein level, and found that all the 7 mesothelioma cell lines tested showed positive staining in CK2α and Gli1 immunohistochemistry. Correlation analysis by Pearson test for CK2α and Gli1 expression in the 75 mesothelioma tumors and the 7 mesothelioma cell lines showed that the two protein expression was significantly correlated (n = 82, r = 0.554, P < 0.01). Furthermore, we demonstrated that Gli1 expression and transcriptional activity were down-regulated after CK2α was silenced in two mesothelioma cell lines (H28 and H2052). CK2α siRNA also down-regulated the expression of Hh target genes in these cell lines. Moreover, treatment with a small-molecule CK2α inhibitor CX-4945 led to dose-dependent inhibition of Gli1 expression and transcriptional activity. Conversely, forced over-expression of CK2α resulted in an increase in Gli1 transcriptional activity in H28 cells. CONCLUSIONS: Thus, we report for the first time that over-expressed CK2α positively regulate Hh/Gli1 signaling in human mesothelioma.

Lung tumourigenesis in a conditional Cul4A transgenic mouse model.

Cullin4A (Cul4A) is a scaffold protein that assembles cullin-RING ubiquitin ligase (E3) complexes and regulates many cellular events, including cell survival, development, growth and cell cycle control. Our previous study suggested that Cul4A is oncogenic in vitro, but its oncogenic role in vivo has not been studied. Here, we used a Cul4A transgenic mouse model to study the potential oncogenic role of Cul4A in lung tumour development. After Cul4A over-expression was induced in the lungs for 32 weeks, atypical epithelial cells were observed. After 40 weeks, lung tumours were visible and were characterized as grade I or II adenocarcinomas. Immunohistochemistry (IHC) revealed decreased levels of Cul4A-associated proteins p21(CIP1) and tumour suppressor p19(ARF) in the lung tumours, suggesting that Cul4A regulated their expression in these tumours. Increased levels of p27(KIP1) and p16(INK4a) were also detected in these tumours. Moreover, the protein level of DNA replication licensing factor CDT1 was decreased. Genomic instability in the lung tumours was further analysed by the results from pericentrin protein expression and array comparative genomic hybridization analysis. Furthermore, knocking down Cul4A expression in lung cancer H2170 cells increased their sensitivity to the chemotherapy drug cisplatin in vitro, suggesting that Cul4A over-expression is associated with cisplatin resistance in the cancer cells. Our findings indicate that Cul4A is oncogenic in vivo, and this Cul4A mouse model is a tool in understanding the mechanisms of Cul4A in human cancers and for testing experimental therapies targeting Cul4A.

Diving associated coral breakage in Hong Kong: differential susceptibility to damage.

We conducted the first quantitative assessment of coral breakage along a gradient of diving activities in Hong Kong, the most densely populated city in southern China. A survey of six 1 × 25 m transects at seven sites revealed a total of 81 broken corals, among which 44% were branching, 44% plate-like and 12% massive. There were 3-19 broken colonies per site. At most study sites, the percentage of broken corals exceeded the recommended no-action threshold of 4%, suggesting that management intervention is justified. There was a significant positive correlation between the number of broken coral colonies and the number of divers visiting the site. The branching Acropora and the plate-like Montipora suffered from much higher frequency of damage than their relative abundance, raising the concern that the cumulative impact of such differential susceptibility to breakage may affect coral community composition.

Genome-wide copy number analysis of cerebrospinal fluid tumor cells and their corresponding archival primary tumors.

A debilitating complication of breast cancer is the metastatic spread of tumor cells to the leptomeninges or cerebrospinal fluid (CSF). Patients diagnosed with this aggressive clinical syndrome, known as leptomeningeal carcinomatosis, have very poor prognosis. Despite improvements in detecting cerebrospinal fluid tumor cells (CSFTCs), information regarding their molecular biology is extremely limited. In our recent work, we utilized a protocol previously used for circulating tumor cell isolation to purify tumor cells from the CSF. We then performed genomic characterization of CSFTCs as well as archival tumors from the same patient. Here, we describe the microarray data and quality controls associated with our study published in the Cancer Research journal in 2013 [1]. We also provide an R script containing code for quality control of microarray data and assessment of copy number calls. The microarray data has been deposited into Gene Expression Omnibus under accession # GSE46068.

The prognostic implications of macrophages expressing proliferating cell nuclear antigen in breast cancer depend on immune context.

Tumor associated macrophages (TAMs) are recruited from the circulation to the tumor site, and can undergo a spectrum of phenotypic changes, with two contrasting activation states described in the literature: the M1 and M2 phenotypes. We previously identified a population of TAMs that express proliferating cell nuclear antigen (PCNA) and are associated with high grade, hormone receptor negative breast cancers and poor outcomes. In the present exploratory study we again found that high PCNA(+) TAM counts in pre-treatment tumor biopsies (102 invasive breast cancer cases from the I-SPY 1 Trial, a prospective neoadjuvant trial with serial core biopsies and gene array data) were associated with high grade, hormone receptor negativity, and decreased recurrence free survival. We explored the association of these PCNA(+) TAMs with the expression of M1 and M2 related genes and, contrary to expectation, observed that high PCNA(+) TAM levels were associated with more M1- than M2-related genes. An immune gene signature, derived from cytotoxic T cell and MHC Class II genes (Tc/ClassII), was developed and we found that high PCNA(+) TAM counts, in the context of a low Tc/ClassII signature score, were associated with significantly worse recurrence free survival in all cases and in hormone receptor negative only cases. We observed similar results using a gene signature-proxy for PCNA(+) TAMs in a larger independent set of 425 neoadjuvant-treated breast cancer cases. The results of this exploratory study indicate that high numbers of PCNA(+) TAMs, in the absence of an anti-tumor immune microenvironment (as indicated by a low Tc/ClassII signature score), are associated with poor outcomes in breast cancer patients treated with neoadjuvant chemotherapy. This, along with the observation that PCNA(+) TAMs were associated predominantly with M1-related genes, may provide new insights into the role of the immune microenvironment in breast cancer.

Molecular profiling of tumor cells in cerebrospinal fluid and matched primary tumors from metastatic breast cancer patients with leptomeningeal carcinomatosis.

Although leptomeningeal carcinomatosis is a well-established clinical syndrome, virtually nothing is known about the tumor cells responsible for this particularly aggressive metastatic process. To isolate cerebrospinal fluid-derived tumor cells (CSFTC) from 15 patients with metastatic breast cancer diagnosed with leptomeningeal carcinomatosis, CSF samples were subjected to a two-step method involving immunomagnetic enrichment and fluorescence-activated cell sorting (IE/FACS), a technique previously used for isolating circulating tumor cells (CTC) from blood. CSFTCs were subjected to genome-wide copy number analysis by array comparative genomic hybridization. Genomic profiling was successfully performed for 13 of 15 patients (87%). Copy number analysis in CSFTCs revealed genomic alterations commonly observed in primary breast cancer and CTCs, indicating their malignant origin. Interestingly, 12 (92%) harbored high-level gains on the 8q24 locus, which includes the MYC oncogene. Comparison of CSFTCs against corresponding archival primary tumors in six patients revealed clonal relationships with some divergence. Good concordance among serial samples attested to the reproducibility of the assay. Our approach for isolation and molecular analysis of CSFTCs yielded new insights into the molecular nature of these cells. Further genomic and functional analyses may help elucidate mechanisms by which tumor cells metastasize to the central nervous system.

Molecular profiling of human mammary gland links breast cancer risk to a p27(+) cell population with progenitor characteristics.

Early full-term pregnancy is one of the most effective natural protections against breast cancer. To investigate this effect, we have characterized the global gene expression and epigenetic profiles of multiple cell types from normal breast tissue of nulliparous and parous women and carriers of BRCA1 or BRCA2 mutations. We found significant differences in CD44(+) progenitor cells, where the levels of many stem cell-related genes and pathways, including the cell-cycle regulator p27, are lower in parous women without BRCA1/BRCA2 mutations. We also noted a significant reduction in the frequency of CD44(+)p27(+) cells in parous women and showed, using explant cultures, that parity-related signaling pathways play a role in regulating the number of p27(+) cells and their proliferation. Our results suggest that pathways controlling p27(+) mammary epithelial cells and the numbers of these cells relate to breast cancer risk and can be explored for cancer risk assessment and prevention.

Inhibition of CK2α down-regulates Notch1 signalling in lung cancer cells.

Protein kinase CK2 is frequently elevated in a variety of human cancers. The Notch1 signalling pathway has been implicated in stem cell maintenance and its aberrant activation has been shown in several types of cancer including lung cancer. Here, we show, for the first time, that CK2α is a positive regulator of Notch1 signalling in lung cancer cell lines A549 and H1299. We found that Notch1 protein level was reduced after CK2α silencing. Down-regulation of Notch1 transcriptional activity was demonstrated after the silencing of CK2α in lung cancer cells. Furthermore, small-molecule CK2α inhibitor CX-4945 led to a dose-dependent inhibition of Notch1 transcriptional activity. Conversely, forced overexpression of CK2α resulted in an increase in Notch1 transcriptional activity. Finally, the inhibition of CK2α led to a reduced proportion of stem-like CD44 + /CD24- cell population. Thus, we report that the inhibition of CK2α down-regulates Notch1 signalling and subsequently reduces a cancer stem-like cell population in human lung cancer cells. Our data suggest that CK2α inhibitors may be beneficial to the lung cancer patients with activated Notch1 signalling.

Understanding the underwater behaviour of scuba divers in Hong Kong.

Diving-related activities may constitute a major threat to coral reefs. This study aimed to quantify the impact of diving in Hong Kong on hard corals and understand how socio-economic characteristics and experience level of divers influence diver-inflicted damage. We recorded and analysed the underwater behaviour of 81 recreational divers. On average, a diver was in contact with marine biota 14.7 times with about 40% of contacts involved corals and 38% were damaging contacts with corals or other biota in a single dive. The most harm-inflicting groups included inexperienced and camera-carrying divers. Although Hong Kong divers did not make many damaging contacts with corals, there is still an imminent need to determine the scale of damage from diving activities on the marine ecosystem given the rapid development of marine-based tourism and the limited coral-inhabited areas in Hong Kong where the marine environment is already under stress from anthropogenic activities.

Elevated levels of proliferating and recently migrated tumor-associated macrophages confer increased aggressiveness and worse outcomes in breast cancer.

PURPOSE: Macrophages play a major role in inflammatory processes and have been associated with poor prognosis in a variety of cancers, including breast cancer. Previously, we investigated the relationship of a subset of tumor-associated macrophages (PCNA(+) TAMs) with clinicopathologic characteristics of breast cancer. We reported that high PCNA(+) TAM counts were associated with hormone receptor (HR)-negative, high-grade tumors and early recurrence. To further understand the significance of elevated PCNA(+) TAMs and the functionality of TAMs, we examined the expression of S100A8/S100A9 with the antibody Mac387. The heterodimeric S100A8/S100A9 complex plays a role in inflammation and is increased in several cancer types. METHODS: We performed immunohistochemistry using the Mac387 antibody on 367 invasive human breast cancer cases. Results were compared to previous PCNA(+) TAM counts and were correlated with patient outcomes adjusting for HR status and histologic grade. RESULTS: Like PCNA(+) TAMs, high Mac387 counts were associated with HR negativity, high tumor grade, younger age, and decreased recurrence-free survival. Mac387, however, appears to identify both a subset of macrophages and a subset of tumor cells. The concordance between Mac387 and PCNA(+) TAM counts was low and cases that had both high Mac387 and high PCNA(+) TAMs counts had a stronger association with early recurrence. CONCLUSIONS: The presence of high numbers of PCNA(+) TAMs and Mac387-positive cells in breast cancers with poor outcomes may implicate a subset of TAMs in breast cancer pathogenesis, and may ultimately serve to develop potential cellular targets for therapeutic interventions.

Leukocyte composition of human breast cancer.

Retrospective clinical studies have used immune-based biomarkers, alone or in combination, to predict survival outcomes for women with breast cancer (BC); however, the limitations inherent to immunohistochemical analyses prevent comprehensive descriptions of leukocytic infiltrates, as well as evaluation of the functional state of leukocytes in BC stroma. To more fully evaluate this complexity, and to gain insight into immune responses after chemotherapy (CTX), we prospectively evaluated tumor and nonadjacent normal breast tissue from women with BC, who either had or had not received neoadjuvant CTX before surgery. Tissues were evaluated by polychromatic flow cytometry in combination with confocal immunofluorescence and immunohistochemical analysis of tissue sections. These studies revealed that activated T lymphocytes predominate in tumor tissue, whereas myeloid lineage cells are more prominant in "normal" breast tissue. Notably, residual tumors from an unselected group of BC patients treated with neoadjuvant CTX contained increased percentages of infiltrating myeloid cells, accompanied by an increased CD8/CD4 T-cell ratio and higher numbers of granzyme B-expressing cells, compared with tumors removed from patients treated primarily by surgery alone. These data provide an initial evaluation of differences in the immune microenvironment of BC compared with nonadjacent normal tissue and reveal the degree to which CTX may alter the complexity and presence of selective subsets of immune cells in tumors previously treated in the neoadjuvant setting.