Sequential metastases of colorectal cancer: Immunophenotypes and spatial distributions of infiltrating immune cells in relation to time and treatments

The role of the immune system in the course of colorectal cancer has been elucidated in the last decade. While quantification of immune cell infiltrates within the resected specimen at diagnosis has a clear power to estimate the prognosis of the patient, the role of infiltrating immune cells within the metastatic situation and especially within the metastatic lesion itself requires further detailed analyses. Recent analyses of infiltrates in colorectal cancer liver metastases revealed a role for the infiltrate density not only for prognosis but also in the prediction of treatment response. This not only broadens the view on these infiltrates and indicates a systematic role of the local immunological microenvironment, but also raises the question how these infiltrates change during repeated courses of treatment (i.e., resection, chemotherapy, etc.). To address this question, sequential lung or sequential liver metastases of colorectal cancer patients were analyzed using whole slide image quantification after immunohistochemical staining against CD3, CD8, FOXP3, CD68 and Granzyme B. The clinical data and interventions were associated with each individual patient and the metastatic lesions. The resulting cell densities reveal a heterogeneous profile: after successful treatment of a metastatic lesion, the recurrent lesion can still have the same immunophenotype with similar cell distributions. In a situation of a favorable immune cell profile, this profile can return and apparently convey a similar favorable course throughout the disease. But also the opposite was found: the recurrent metastatic lesion could have a different profile with alterations in specific immune cell subsets over time. Further analyses are required to elucidate the different patterns and their associations to the treatment, the tumor cell phenotype and other dynamic factors. However, it is clear from this data however, that there is an immune cell plasticity that needs to be analyzed for individual patients.

Abstract 1987: Molecular characterization of the breast cancer-associated antigen NY-BR-1

Breast cancer is one of the most common malignancies with increasing incidence every year and a leading cause of death among women. Although early stage breast cancer can be effectively treated, there are limited numbers of treatment options available for patients with advanced and metastatic disease.

The breast cancer associated antigen NY-BR-1 was identified by a serological screening strategy (SEREX). NY-BR-1 is expressed in the majority (>70%) of breast tumors as well as metastases, in normal breast tissue, in testis, and occasionally in prostate tissue. NY-BR-1 was confirmed as an immunogenic antigen as we could detect NY-BR-1 specific spontaneous humoral and cellular immune responses in several breast cancer patients.

However, biological function, regulatory mechanisms, and interaction partners of NY-BR-1 are still unknown. Therefore, we combined integrative functional analysis (genomics, transcriptomics and epigenetics) and experiments to unravel the transcriptional regulation of NY-BR-1 and to detect its function within the mammary gland.

As numerous binding sites for nuclear hormone receptors (e.g. Estrogen Receptor alpha, Progesterone receptor and Glucocorticoid receptor) and CpG islands were predicted within the promoter sequence of NY-BR-1, primary-tissues from breast reductions or tumor cells obtained from pleural effusions were treated with different hormones (Estradiol, Dexamethasone, Progesterone, Retinoic acid, Vitamin D) or with the HDAC inhibitors Valproic acid, Trichostatin A and the demethylating agent 5´Aza-Deoxycytidine in order to analyze the transcriptional regulation of NY-BR-1.

Additionally, we analyzed the methylation status at various sites within the promoter region of NY-BR-1 using EpiTyper MassARRAY technology and publicly available resources such as the TCGA database. Here, we present preliminary results of our analysis and evaluate their implication for further investigation of NY-BR-1.

Citation Format: Julia Bitzer, Zeynep Kosaloglu, Niels Halama, Claudia Ziegelmeier, Tina Lerchl, Anna Spille, Maria Pudenz, Eva Koellensperger, Stefan Eichmueller, Wolfram Osen, Andreas Schneeweiss, Frederik Marmé, Inka Zoernig, Dirk Jaeger. Molecular characterization of the breast cancer-associated antigen NY-BR-1. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1987. doi:10.1158/1538-7445.AM2015-1987

Hepatic metastases of colorectal cancer are rather homogeneous but differ from primary lesions in terms of immune cell infiltration

The immune system plays an important role in shaping the clinical course of colorectal cancer (CRC). However, it is still unclear how the immune infiltrates of primary CRC lesions and distant metastases by immune effector cells are related to each other. To address this issue, we quantified CD3⁺, CD8⁺ and granzyme B⁺ lymphocytes in primary CRC samples and corresponding liver metastases. This analysis showed that the prognostic predictions that can be drawn from the infiltration of immune cells in primary CRCs and their metastases are heterogeneous. To investigate whether such heterogeneity would also be observed within CRC hepatic metastases, the density of the immune infiltrate and cytokine production were assessed in opposite sides of the same metastatic lesion. In addition, tumor-infiltrating lymphocytes were assessed in sequential sections of the same metastatic lesion, with a spacing of 30 μm. In summary, consistent cell counts and cytokine levels were detected within the same lesion. The study of a case of synchronous metastases, however, suggested that different metastatic lesions within the same patient may be heterogeneous, perhaps indicating a major impact for local causes on tumor infiltration by immune cells. In summary, our study demonstrates a consistent degree of heterogeneity between primary tumors and hepatic metastases but an excellent intra-lesional homogeneity. These findings may be of key importance for patient stratification and the development of personalized strategies against CRC.

Localization and density of immune cells in the invasive margin of human colorectal cancer liver metastases are prognostic for response to chemotherapy

Analysis of tumor-infiltrating lymphocytes (TIL) in primary human colorectal cancer (CRC) by in situ immunohistochemical staining supports the hypothesis that the adaptive immune response influences the course of human CRC. Specifically, high densities of TILs in the primary tumor are associated with good prognosis independent of other prognostic markers. However, the prognostic role of TILs in metastatic CRC lesions is unknown, as is their role in response or resistance to conventional chemotherapy. We analyzed the association of TIL densities at the invasive margin of CRC liver metastases with response to chemotherapy and progression-free survival in a set of 101 large section samples. High-resolution automated microscopy on complete tissue sections was used to objectively generate cell densities for CD3, CD8, granzyme B, or FOXP3 positive immune cells. A predictive scoring system using TIL densities was developed in a training set and tested successfully in an independent validation set. TIL densities at the invasive margin of liver metastases allowed the prediction of response to chemotherapy with a sensitivity of 79% and specificity of 100%. The association of high density values with longer progression-free survival under chemotherapy was statistically significant. Overall, these findings extend the impact of the local immune response on the clinical course from the primary tumor also to metastatic lesions. Because detailed quantification of TILs in metastatic lesions revealed a strong association with chemotherapy efficacy and prognosis, we suggest that the developed scoring system may be used as a predictive tool for response to chemotherapy in metastatic CRC.

Abstract 795: Patterns of T-cell distribution at the invasive margin of colorectal cancer liver metastases: Downstream recruitment of T cells and spatial heterogeneity

The local immunological cancer microenvironment influences the clinical course of colorectal cancer. The interface between colorectal cancer liver metastases and adjacent normal liver represents a clear border. Typically, T cells in the vicinity of the tumor are located on the stromal compartment of the tumor and only few cells are in direct contact with the tumor epithelium. Patterns of T cell distribution at the invasive margin are heterogeneous and have not been analyzed systematically. Using high-throughput whole slide imaging technology, tissue areas of 1 mm2 size were analyzed for precise T cell density and localization, showing distinct density patterns of localization in relation to the malignant tissue across the invasive margins of samples from different patients. Unsupervised clustering revealed distinct patterns: regions with T cells in close contact to the tumor usually had significantly elevated T cell numbers further away from the tumor, whereas the other groups showed limited enrichment. Additionally, in the distance of around 20 to 40 µm from the tumor a decrease in T cells was found. The distribution of the cells in the tissues could be accounted for by cell-matrix interactions, immune cell – immune cell interactions or chemotactic fields potentially generated by tumor or other cells. Direct T cell – tumor interaction however leads to subsequent far-reaching attraction and activation of T cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 795. doi:10.1158/1538-7445.AM2011-795

Quantification of prognostic immune cell markers in colorectal cancer using whole slide imaging tumor maps

OBJECTIVE

To analyze intratumoral heterogeneity of immune cells and the resulting impact of heterogeneity on the level of individual patient prediction.

STUDY DESIGN

Using whole slide imaging by virtual microscopy, we present the first spatial quantitative study of immune cells in a set of colorectal cancer primary tumors. We generated "tumor maps" based on cell densities in fields of 1 mm2, visualizing intratumoral heterogeneity. In this example, cutoffs of marker-based cell stains identified by tissue microarray (TMA) led to ambiguous decisions in 11 of the 20 patients studied. Classic TMA analysis can be used in large patient cohorts to generate clinically significant predictors. The transfer of these predictors from large-scale TMA to individualized predictions thus far has not been investigated. In colorectal cancer, TMA-based quantitative immune cell counts using immune cell surface molecules (CD3, CD8, Granzyme B, and CD45RO) have been shown to be potentially better predictors for patient survival than the classical TNM system.

RESULTS

Our results make clear that for individualized prognostic evaluations, whole slide imaging by virtual microscopy is irreplaceable during identification of prognostic markers as well as in their subsequent application.

CONCLUSION

In the future, spatial marker signatures could contribute to individual patient classifiers.

Estimation of immune cell densities in immune cell conglomerates: an approach for high-throughput quantification

BACKGROUND

Determining the correct number of positive immune cells in immunohistological sections of colorectal cancer and other tumor entities is emerging as an important clinical predictor and therapy selector for an individual patient. This task is usually obstructed by cell conglomerates of various sizes. We here show that at least in colorectal cancer the inclusion of immune cell conglomerates is indispensable for estimating reliable patient cell counts. Integrating virtual microscopy and image processing principally allows the high-throughput evaluation of complete tissue slides.

METHODOLOGY/PRINCIPAL FINDINGS

For such large-scale systems we demonstrate a robust quantitative image processing algorithm for the reproducible quantification of cell conglomerates on CD3 positive T cells in colorectal cancer. While isolated cells (28 to 80 microm(2)) are counted directly, the number of cells contained in a conglomerate is estimated by dividing the area of the conglomerate in thin tissues sections (< or =6 microm) by the median area covered by an isolated T cell which we determined as 58 microm(2). We applied our algorithm to large numbers of CD3 positive T cell conglomerates and compared the results to cell counts obtained manually by two independent observers. While especially for high cell counts, the manual counting showed a deviation of up to 400 cells/mm(2) (41% variation), algorithm-determined T cell numbers generally lay in between the manually observed cell numbers but with perfect reproducibility.

CONCLUSION

In summary, we recommend our approach as an objective and robust strategy for quantifying immune cell densities in immunohistological sections which can be directly implemented into automated full slide image processing systems.