Improving Academic Biobank Value and Sustainability Through an Outputs Focus.

Although it is generally accepted that human tissue biobanks are important to facilitate progress in health and medical research, many academic biobanks face sustainability challenges. We propose that biobank sustainability is challenged by a lack of available data describing the outputs and benefits that are produced by biobanks, as reflected by a dearth of publications that enumerate biobank outputs. We further propose that boosting the available information on biobank outputs and using a broader range of output metrics will permit economic analyses such as cost-consequence analyses of biobank activity. Output metrics and cost-consequence analyses can allow biobanks to achieve efficiencies, and improve the quality and/or quantity of their outputs. In turn, biobank output measures provide all stakeholders with explicit and accountable data on biobank value, which could contribute to the evolution of biobank operations to best match research needs, and mitigate some threats to biobank sustainability.

Precision medicine: Driving the evolution of biobanking quality.

The promise of precision medicine will only be realized if the healthcare system adapts to meet some key infrastructure needs. Among these needs are adequate biobanking practices, capable of producing the biological samples and data that precision medicine relies upon in both the research and clinical phases. Within the research domain, there have been significant improvements to biobanking processes over the past two decades, driven by increased understanding of the impact of pre-analytical variability and the critical role of biospecimen and data quality. In the era of precision medicine, biobanking to support clinical needs has similar quality requirements. The extensive knowledge and resources that have been developed by the research biobanking community are available for adoption by clinical biobanking. The challenge and opportunity now presented to the healthcare system is to adopt or adapt these resources, for example, external biobanking standards and verification programs.

Characteristics and outcome of the COEUR Canadian validation cohort for ovarian cancer biomarkers.

BACKGROUND: Ovarian carcinoma is the most lethal gynecological malignancy due to early dissemination and acquired resistance to platinum-based chemotherapy. Reliable markers that are independent and complementary to clinical parameters are needed to improve the management of patients with this disease. The Canadian Ovarian Experimental Unified Resource (COEUR) provides researchers with biological material and associated clinical data to conduct biomarker validation studies. Using standards defined by the Canadian Tissue Repository Network (CTRNet), we have previously demonstrated the quality of the biological material from this resource. Here we describe the clinical characteristics of the COEUR cohort. METHODS: With support from 12 Canadian ovarian cancer biobanks in Canada, we created a central retrospective cohort comprised of more than 2000 patient tissue samples with associated clinical data, including 1246 high-grade serous, 102 low-grade serous, 295 endometrioid, 259 clear cell and 89 mucinous carcinoma histotypes. A two-step reclassification process was applied to assure contemporary histological classification (histotyping). For each histotypes individually, we evaluated the association between the known clinico-pathological parameters (stage, cytoreduction, chemotherapy treatment, BRCA1 and BRCA2 mutation) and patient outcome by using Kaplan-Meier and Cox proportional hazard regression analyses. RESULTS: The median follow-up time of the cohort was 45 months and the 5-year survival rate for patients with high-grade serous carcinomas was 34%, in contrast to endometrioid carcinomas with 80% at 5 years. Survival profiles differed by histotype when stratified by stage or cytoreduction. Women with mucinous or clear cell carcinomas at advanced stage or with non-optimally debulked disease had the worst outcomes. In high-grade serous carcinoma, we observed significant association with longer survival in women harboring BRCA1 or BRCA2 mutation as compared to patients without detectable mutation. CONCLUSIONS: Our results show the expected survival rates, as compared with current literature, in each histotype suggesting that the cohort is an unbiased representation of the five major histotypes. COEUR, a one stop comprehensive biorepository, has collected mature outcome data and relevant clinical data in a comprehensive manner allowing stratified analysis.

Clonal evolution of high-grade serous ovarian carcinoma from primary to recurrent disease.

High-grade serous carcinoma (HGSC) is the most common and fatal form of ovarian cancer. While most tumours are highly sensitive to cytoreductive surgery and platinum- and taxane-based chemotherapy, the majority of patients experience recurrence of treatment-resistant tumours. The clonal origin and mutational adaptations associated with recurrent disease are poorly understood. We performed whole exome sequencing on tumour cells harvested from ascites at three time points (primary, first recurrence, and second recurrence) for three HGSC patients receiving standard treatment. Somatic point mutations and small insertions and deletions were identified by comparison to constitutional DNA. The clonal structure and evolution of tumours were inferred from patterns of mutant allele frequencies. TP53 mutations were predominant in all patients at all time points, consistent with the known founder role of this gene. Tumours from all three patients also harboured mutations associated with cell cycle checkpoint function and Golgi vesicle trafficking. There was convergence of germline and somatic variants within the DNA repair, ECM, cell cycle control, and Golgi vesicle pathways. The vast majority of somatic variants found in recurrent tumours were present in primary tumours. Our findings highlight both known and novel pathways that are commonly mutated in HGSC. Moreover, they provide the first evidence at single nucleotide resolution that recurrent HGSC arises from multiple clones present in the primary tumour with negligible accumulation of new mutations during standard treatment.

Applying Findable, Accessible, Interoperable, and Reusable Principles to Biospecimens and Biobanks.

The importance of stimulating greater sharing of data for use and reuse in health research is widely recognized. To this end, the findable, accessible, interoperable, and reusable (FAIR) principles for data have been developed and widely accepted in the research community. Research biospecimens are a resource that leads to much of this health research data but are also a form of data. Therefore, the FAIR principles should apply to biospecimens. Nevertheless, there is a widespread problem of not sharing biospecimen resources that is clearly visible within the research arena. The impacts of this are likely to include diversion of precious research funds into compiling duplicate biospecimen cohorts, detraction from research productivity as researchers compete for and create duplicate resources, and deterrence of attempts to assess research reproducibility. This article explores some of the barriers that may limit availability of FAIR biospecimens. These barriers relate to the type of biospecimen collections and the characteristics of the custodians that influence their intention and interest in sharing. Barriers also relate to the ethical, legal, and social issues concerning collections, the research context of the collections, and cost and expertise involved in repurposing collections to enable sharing. Several solutions to increase sharing are identified. Some have recently been implemented, including enhancing biospecimen locators with tools to guide researchers and facilitating transfer of research collections to centralized biobank infrastructures at the conclusion of projects. New proposed solutions include improving search capabilities within publication databases, and introduction of evidence-based justifications for all new collections into peer-reviewed grant competition processes. It is recognized that there are both scientific factors and practical reasons that can impose limits to sharing biospecimens. However, funding availability, productivity, and progress in health research all stand to benefit from improved sharing of research biospecimen collections.

An Approach to Evaluate the Costs and Outputs of Academic Biobanks.

Academic biobanks commonly report sustainability challenges, which may be exacerbated by a lack of information on biobank value. To better understand the costs and supported outputs that contribute to biobank value, we developed a systematic, generalizable methodology to determine biobank inputs and publications arising from biobank-supported research. We then tested this in a small cohort (n = 12) of academic cancer biobanks in New South Wales, Australia. A proforma was developed to capture monetary and in-kind biobank costing data from biobank managers and publicly available sources. Participating biobanks were grouped and compared according to the following two classifications: open- versus restricted-access and high versus low total annual costs. Our methodology provides a feasible approach for capturing comprehensive costing data for a defined period. Characterization of biobanks using this approach showed that median total costs, as well as median staffing and in-kind costs, were comparable for open- and restricted-access biobanks, as were the quantity and journal impact metrics of supported publications. High- and low-cost biobanks supported similar median numbers of publications; however, high-cost biobanks supported publications with higher median journal impact factor and Altmetric scores. Overall, 9 of 10 biobanks had higher Field-Weighted Citation Impact scores than the global average for similar publications. This is the first tested, generalizable approach to analyze the costs and publications arising from biobank-supported research. By determining explicit cost and output data, academic biobanks, funders, and policymakers can engage in or support informed redirection of resourcing and/or benchmark setting with the aim of improving biobank support of research.

Incorporating Equity, Diversity and Inclusion in a Canadian Biobank.

Equity, diversity, and inclusion (EDI) is an established concept and is an important issue in health research. It is now recognized that measures to address EDI in research can have a positive impact on the value of health research outputs and health outcomes based on this knowledge. EDI strategies, guidelines, and education and training are now embraced by national research funders and local research organizations. However, these initiatives are very broad and not specific to the field of biobanking. We have, therefore, set out to develop and implement a formal research biobank EDI action plan. This article describes the creation of an EDI action plan that provides an intentional approach to identifying and achieving EDI actions and priorities for our research biobank. The plan is framed by the definitions of EDI and an understanding of the topics, issues, and groups within the EDI field. The plan is founded on a set of guiding principles and delineates three pillars of work that align with team, participant, and researcher domains. The plan identifies a set of 31 actions that are categorized by implementation time frames, in order to positively address EDI issues across these pillars. The completion of these actions will help us to mitigate against bias and enrich our biobanking and research services. Ultimately, our goal is to realize more diverse participation in research supported by our biobank. This would support health research to explore and better understand differences in disease biology and the efficacy of medical treatments across all people.

The autophagy protein LC3A correlates with hypoxia and is a prognostic marker of patient survival in clear cell ovarian cancer.

Clear cell ovarian cancer histotypes exhibit metabolic features associated with resistance to hypoxia and glucose deprivation-induced cell death. This metabolic characteristic suggests that clear cell ovarian cancers activate survival mechanisms not typical of other epithelial ovarian cancers. Here we demonstrate that microtubule-associated protein 1 light chain 3A (LC3A), a marker of autophagy, is related to hypoxia and poor prognosis in clear cell ovarian cancer. In 485 ovarian tumours, we found that LC3A was significantly associated with poor progression-free (p = 0.0232), disease-specific (p = 0.0011) and overall patient survival (p = 0.0013) in clear cell ovarian cancer patients, but not in other subtypes examined. LC3A was an independent prognostic marker of reduced disease-specific [hazard ratio (HR): 2.55 (95% CI 1.21-5.37); p = 0.014] and overall survival [HR: 1.95 (95% CI 1.00-3.77); p = 0.049] in patients with clear cell ovarian carcinoma. We also found a strong link between autophagy and hypoxia as LC3A staining revealed a significant positive association with the hypoxia-related proteins carbonic anhydrase-IX and HIF-1α. The functional link between hypoxia and autophagy was demonstrated using clear cell and high-grade serous cell lines that were subjected to hypoxia or hypoxia + glucose deprivation. Clear cell carcinoma lines displayed greater autophagy induction and were subsequently more sensitive to inhibition of autophagy under hypoxia compared to the high-grade serous lines. Together, our findings indicate that hypoxia-induced autophagy may be crucial to the clinical pathology of clear cell ovarian cancer and is a potential explanation for histological subtype differences in patient disease progression and outcomes.

Frequent somatic mutations in PTEN and TP53 are mutually exclusive in the stroma of breast carcinomas.

We have recently shown that loss of heterozygosity of specific markers, including those at 10q23, 17p13-p15 and 16q24, can occur in the stromal and epithelial compartments of primary invasive breast carcinomas. Here, we demonstrate high frequencies of somatic mutations in TP53 (encoding tumor protein p53) and PTEN (encoding phosphate and tensin homolog) in breast neoplastic epithelium and stroma. Mutations in TP53 and PTEN are mutually exclusive in either compartment. In contrast, mutations in WFDC1 (16q24, encoding WAP four-disulfide core domain 1) occur with low frequency in the stroma.

The Availability of Human Biospecimens to Support Biomarker Research.

Preserved biospecimens held in biobank inventories and clinical archives are important resources for biomarker research. Recent advances in technologies have led to an increase in use of clinical archives in particular, in order to study retrospective cohorts and to generate data relevant to tissue biomarkers. This raises the question of whether the current sizes of biobank inventories are appropriate to meet the demands of biomarker research. This commentary discusses this question by considering data concerning overall biobank and biospecimen numbers to estimate current biospecimen supply and use. The data suggests that biospecimen supply exceeds current demand. Therefore, it may be important for individual biobanks to reassess the targets for their inventories, consider culling unused portions of these inventories, and shift resources towards providing prospective custom biobanking services.

The different prognostic significance of polysialic acid and CD56 expression in tumor cells and lymphocytes identified in breast cancer.

Protein glycosylation, the attachment of carbohydrates onto proteins, is a fundamental process that alters the biological activity of proteins. Changes to glycosylation states are associated with many forms of cancer including breast cancer. Through immunohistological analysis of breast cancer patient tumors, we have discovered the expression of an atypical glycan-polysialic acid (polySia)-in breast cancer. Notably, we have identified polySia expression in not only tumor cells but also on tumor-infiltrating lymphocytes (TILs) and our study reveals ST8Sia4 as the predominant polysialyltransferase expressed. Evaluation of ST8Sia4 expression in tumor cells identified an association between high expression levels and poor patient outcomes whereas ST8Sia4 expression in infiltrating stromal cells was associated with good patient outcomes. Investigation into CD56, a protein known to be polysialylated, found CD56 and polySia expression on breast tumor cells and TILs. CD56 expression did not positively correlate with polySia expression except in patient tumors which expressed HER2. In these HER2 expressing tumors, CD56 expression was significantly associated with HER2 expression score. Evaluation of CD56 tumor cell expression identified a significant association between CD56 expression and poor patient outcomes. By contrast, CD56 expression on TILs was significantly associated with good clinical outcomes. Tumors with CD56+ TILs were also consistently polySia TIL positive. Interestingly, in tumors where TILs were CD56 low-to-negative, a polySia+ lymphocyte population was still identified and the presence of these lymphocytes was a poor prognostic indicator. Overall, this study provides the first detailed report of polySia and CD56 in breast cancer and demonstrates that the prognostic significance is dependent on the cell type expression within the tumor.

Vignettes to Illustrate the Value of Tumor Biobanks in Cancer Research in Canada.

Background: Tumor biobanks are a common research infrastructure. As a collection of biospecimens and annotated data collected to support a multitude of research projects, biobanks facilitate access to materials that are the critical fuel for the generation of data in up to 40% of cancer research publications. However, quantifying how to measure biobanks' impact and their value on the field of cancer research discoveries and findings, has not been well elucidated. Methods: We have used a qualitative case study approach to illustrate the impact of tumor biobanks. We assessed the impact of three research studies published between 2010 and 2012 that required easily accessible "classic" biobanks. Each study utilized preassembled collections of tumor biospecimens with associated patient outcomes data at the outset of the research project. We compared the resulting journal impact factor, altmetric and field-weighted citation impact factor scores for each article to a set of six "benchmark" articles that represent cancer research and treatment discoveries from the same time period and two sentinel scientific discovery articles. Results: We developed a value model using a literature search and design-thinking methodologies to illustrate the contributions of these "classic" model biobanks to these research studies. Assessment of the three example articles supported by biobanks demonstrates that the output can have impact that is comparable to the impact of a set of benchmark articles describing milestones in the field of cancer research and cancer care. Conclusions: These case studies illustrate the value of the sustained investment of funds, planning, time, and effort on the part of the biobanks before the conduct of the research study to be able to ultimately support high-value research. The "value" model will enable further discussion around impact and may be useful in better delineating qualitative metrics of biobank value in the future.

Analysis of Trends in Biospecimen Complexity in Cancer Research Over Two Decades.

Background: Over time, researchers' demand for increased quality and quantity of biospecimens has risen. However, quality is multifaceted, ranging from simple to complex, and comes at a cost. Therefore, to be sustainable and ensure optimal utilization of their resources (supply), biobanks must consider the trends in biospecimen use to predict the needs for future biospecimen quality (demand). Methods: An unbiased selection process was used to identify research articles from across the spectrum of cancer research from the PubMed database. A set of 225 articles utilizing human biospecimens were randomly selected for review (75 articles from each of three time intervals; 2000, 2010, 2020). Criteria for determining the source and complexity of quality of biospecimens were developed and overall concordance between two independent observers abstracting the data was then confirmed (k = 0.87) to validate the criteria. Results: We observed increased use of dual biospecimen formats (20%-36% of articles, p = 0.03), matched samples (16%-37% of articles, p = 0.0033), and biospecimens with associated outcomes data (20%-49%, p = 0.0002). In addition, the use of two or more cohorts increased over time (p = 0.03). The mechanism through which biospecimens were obtained also changed over time with an increase in the diversity of collection pathways used (p = 0.006). Conclusions: The complexity of biospecimens being used in cancer research and the diversity of collection pathways through which these are obtained has changed significantly. This observation is important for biobanks given that the cost to support the supply of biospecimens with complex extrinsic as opposed to simple intrinsic quality characteristics is greater. For biobanks to manage sustainability, optimize utilization, and meet changing research demand, they may need to adjust their operational models to better support the supply of these types of biospecimens.

Finding the Value in Biobanks: Enhancing the CTRNet Locator.

Biobanks are a critical piece of Research Infrastructure (RI). However, biobanks need to accept the reality of a life cycle for RIs. Until recently, strategies to sustain biobanks have been commonly focused on ways to maintain current operational models. However, sustaining biobanks as they exist today may be increasingly challenging in the face of the disruption in health and research priorities caused by the COVID-19 pandemic. In this opinion article, we review the current and emerging future drivers of biobank value for their researchers, institutions, and funders, highlighting utilization and impact of research performed using the biobank as key measures of future value. While biobanks can only indirectly influence the specific impact of the research performed, they can transform themselves to more actively redefine utilization to their advantage. Utilization means more than the balance of samples and data in versus out. Utilization means redirecting expertise to best support end users, and importantly, closing the operating gap between biobanks and their end users who seek to find the right biospecimens and data to pursue their research. We discuss the specific role of locators (those created by public investment) in closing this gap and the need for additional tools for researchers, before and subsequent to connecting with locators. For the former, we specifically propose that more support is needed to assist researchers in the decision as to how to best obtain biospecimens and navigate the options as to whether finding existing biospecimens and data held by a biobank is the optimal solution for a given project, or whether the optimal solution is either contracting with a biobank to collect samples or creating a new biobank. We believe this type of biospecimen navigator platform will help to maximize utilization of current biobank resources, and also promote the services and expertise in biobanks to better serve researchers' needs.

Principles of reproducible metabolite profiling of enriched lymphocytes in tumors and ascites from human ovarian cancer.

Identifying metabolites and delineating their immune-regulatory contribution in the tumor microenvironment is an area of intense study. Interrogating metabolites and metabolic networks among immune cell subsets and host cells from resected tissues and fluids of human patients presents a major challenge, owing to the specialized handling of samples for downstream metabolomics. To address this, we first outline the importance of collaborating with a biobank for coordinating and streamlining workflow for point of care, sample collection, processing and cryopreservation. After specimen collection, we describe our 60-min rapid bead-based cellular enrichment method that supports metabolite analysis between T cells and tumor cells by mass spectrometry. We also describe how the metabolic data can be complemented with metabolic profiling by flow cytometry. This protocol can serve as a foundation for interrogating the metabolism of cell subsets from primary human ovarian cancer.

Tumor-infiltrating lymphocytes predict response to anthracycline-based chemotherapy in estrogen receptor-negative breast cancer.

INTRODUCTION: Infiltration of breast tumors by tumor-infiltrating lymphocytes (TIL) has been associated with sensitivity to anthracycline-based chemotherapy. However, it is unclear whether this is true within the estrogen receptor-alpha (ER)-negative subset of breast tumors that frequently manifest high TIL levels. METHODS: The association of TIL with short-term and long-term clinical response to anthracycline-based therapy was assessed in two independent ER-negative breast cancer cohorts in which patients were categorized as TIL-high or TIL-low. We defined an eight-gene lymphocyte mRNA expression signature (including CD19, CD3D, CD48, GZMB, LCK, MS4A1, PRF1, and SELL) and used unsupervised hierarchical clustering to examine the association between TIL and short-term response to neoadjuvant chemotherapy in a previously published cohort of ER-negative tumors (n = 113). We also examined the association between TIL and long-term chemotherapeutic efficacy in a second cohort of ER-negative tumors (n = 255) with longer than 6 years of median follow-up by using tissue microarrays and immunohistochemistry (IHC) for detection of CD3, CD8, CD4, CD20, and TIA-1. RESULTS: In patients with ER-negative tumors treated with neoadjuvant anthracycline-based chemotherapy, pathologic complete responses (pCRs) were achieved by 23 (74%) of 31 TIL-high patients and 25 (31%) of 80 TIL-low patients (odds ratio (OR), 6.33; 95% confidence interval (CI), 2.49 to 16.08; P < 0.0001). Multivariate logistic regression with standard clinicopathologic features demonstrated that only tumor size (P = 0.037) and TIL status (P = 0.001) were independent predictors of anthracycline response. In the second cohort, adjuvant anthracycline-based therapy was associated with increased disease-free survival (DFS) only in patients with high levels of intraepithelial CD3+ TIL (P = 0.0023). In contrast, outcomes after CMF treatment (cyclophosphamide, methotrexate, and fluorouracil) showed no association with CD3 status. In both cohorts, cytotoxic T-cells were the primary TIL subtype associated with anthracycline sensitivity. Finally, TIL significantly predicted anthracycline sensitivity for both the Her2-positive and triple-negative tumor phenotypes. CONCLUSIONS: ER-negative breast cancers with high levels of TIL have heightened sensitivity to anthracycline-based chemotherapy, as assessed by the immediate response to neoadjuvant therapy and long-term outcome following adjuvant therapy. Investigations of TIL-based predictive tests to identify patients likely to benefit from anthracycline-based treatments are warranted.

A Permission to Contact Platform Is an Efficient and Cost-Effective Enrollment Method for a Biobank to Create Study-Specific Research Cohorts.

Background: The permission to contact (PTC) platform is a useful mechanism to increase patient engagement and enrollment into biobanks. It provides biobanks with the ability to select specific patient cohorts and to complete consent to facilitate access to biospecimens and data. In this study, we evaluated consenting costs for a biobank to compile a research cohort based on utilizing a PTC platform to obtain consent as compared with utilizing a prospective consenting approach. Methods: In this study, we utilized a PTC platform to conduct an initial selection of potential participants for two breast cancer cohorts and to provide a "referral" to the biobank to recontact these patients to provide consent to access clinical archival biospecimens and associated data. We evaluated the effort, costs, and cohorts compiled by this approach to compare this mechanism with the alternative: compiling the same type of cohorts based on a classic biobank enrollment approach. Results: After initial diagnosis and provision of a PTC up to 12 years before, recontact was possible in 84 of 90 (74%) and 77 of 107 (72%) breast cancer patients for preinvasive (ductal carcinoma in situ [DCIS]) and invasive (triple-negative subtype) cancers. Of those recontacted, consent was completed in 42 of 84 (55%) DCIS patients and 48 of 107 (45%) triple negative breast cancer (TNBC) patients. The total cost of using PTC to recontact patients to compile these two consented cohorts was CAD $26.34 and CAD $20.11 per patient consent, respectively. Conclusions: We have demonstrated the feasibility of utilizing a PTC platform to obtain informed consent from patients for a specific study through referrals provided several years after initial PTC was provided. Depending on the existing biobank operational model and the efficiency of its processes for enrollment and obtaining broad informed consent, the implementation of a PTC platform may be an efficient and cost-effective complementary method for a biobank to enroll patients to develop criteria-specific cohorts to support research.

Building Research Support Capacity across Human Health Biobanks during the COVID-19 Pandemic.

Human health biobanks are forms of research infrastructure that supply biospecimens and associated data to researchers, and therefore juxtapose the activities of clinical care and biomedical research. The discipline of biobanking has existed for over 20 years and is supported by several international professional societies and dedicated academic journals. However, despite both rising research demand for human biospecimens, and the growth of biobanking as an academic discipline, many individual biobanks continue to experience sustainability challenges. This commentary will summarize how the COVID-19 pandemic is creating new challenges and opportunities for both the health biobanking sector and the supporting discipline of biobanking. While the challenges for biobanks may be numerous and acute, there are opportunities for both individual biobanks and the discipline of biobanking to embrace change such that biobanks can continue to support and drive biomedical research. We will therefore describe numerous practical steps that individual biobanks and/or the discipline of biobanking can take to survive and possibly thrive in response to the COVID-19 pandemic.

1-Methylnicotinamide is an immune regulatory metabolite in human ovarian cancer.

Immune regulatory metabolites are key features of the tumor microenvironment (TME), yet with a few exceptions, their identities remain largely unknown. Here, we profiled tumor and T cells from tumor and ascites of patients with high-grade serous carcinoma (HGSC) to uncover the metabolomes of these distinct TME compartments. Cells within the ascites and tumor had pervasive metabolite differences, with a notable enrichment in 1-methylnicotinamide (MNA) in T cells infiltrating the tumor compared with ascites. Despite the elevated levels of MNA in T cells, the expression of nicotinamide N-methyltransferase, the enzyme that catalyzes the transfer of a methyl group from S-adenosylmethionine to nicotinamide, was restricted to fibroblasts and tumor cells. Functionally, MNA induces T cells to secrete the tumor-promoting cytokine tumor necrosis factor alpha. Thus, TME-derived MNA contributes to the immune modulation of T cells and represents a potential immunotherapy target to treat human cancer.

Density of tumour stroma is correlated to outcome after adoptive transfer of CD4+ and CD8+ T cells in a murine mammary carcinoma model.

Adoptive immunotherapy shows promise for the treatment of cancer; however, partial or mixed responses remain common outcomes due to the heterogeneity of tumours. We studied three murine mammary tumour lines that express an ovalbumin-tagged version of HER-2/neu and reproducibly undergo complete regression (CR), partial regression (PR), or progressive disease (PD) after adoptive transfer of ovalbumin-specific CD8(+) (OT-I) and CD4(+) (OT-II) T cells. The three tumour lines were implanted in immunocompetent C57Bl/6 host mice, and established tumours were treated by adoptive transfer of naive OT-I and OT-II T cells. Tumours of the CR and PR classes triggered almost indistinguishable T cell responses in terms of activation, proliferation, trafficking to the tumour site, infiltration of tumour stroma, and intratumoural T cell proliferation; however, tumours of the PR class showed reduced infiltration of tumour epithelium by donor T cells. PD responses were associated with early impairment of T cell activation and proliferation in draining lymph node, followed by negligible infiltration of tumour tissue by donor T cells. Histopathological determinants of outcome were investigated through an unsupervised analysis of 64 untreated tumours representing the three response classes. Tumours of the CR class had proportionately more stroma, which had a looser, more collagen-rich histological appearance. Thus, the amount and composition of tumour stroma distinguished successfully (CR) from unsuccessful (PR or PD) outcomes after adoptive T cell transfer, a finding that might facilitate the design of immunotherapy trials for human breast cancer.