Immunophenotyping of tumor-infiltrating mononuclear cells in ovarian carcinoma

Tumor-Associated Macrophages Expand Chemoresistant, Ovarian Cancer Stem-Like Cells

The persistence of ovarian cancer stem-like cells (OvCSCs) after chemotherapy resistance has been implicated in relapse. However, the ability of these relatively quiescent cells to produce the robust tumor regrowth necessary for relapse remains an enigma. Since normal stem cells exist in a niche, and tumor-associated macrophages (TAMs) are the highest abundance immune cell within ovarian tumors, we hypothesized that TAMs may influence OvCSC proliferation. To test this, we optimized OvCSC enrichment by sphere culture and in vitro polarization of monocytes to a TAM-like M2 phenotype. Using cocultures that permitted the exchange of only soluble factors, we found that M2 macrophages increased the proliferation of sphere cells. Longer-term exposure (5-7 days) to soluble TAM factors led to retention of some stem cell features by OvCSCs but loss of others, suggesting that TAMs may support an intermediate stemness phenotype in OvCSCs. Although TAM coculture decreased the percentage of OvCSCs surviving chemotherapy, it increased the overall number. We therefore sought to determine the influence of this interaction on chemotherapy efficacy in vivo and found that inhibiting macrophages improved chemotherapy response. Comparing the gene expression changes in OvCSCs cocultured with TAMs to publicly available patient data identified 34 genes upregulated in OvCSCs by exposure to soluble TAM factors whose expression correlates with outcome. Overall, these data suggest that TAMs may influence OvCSC proliferation and impact therapeutic response.

Weapons ovarian epithelial tumors may use in immune escape: an immunohistochemical correlational study

Investigate FasL and survivin expression in a series of primary ovarian surface epithelial tumors, correlate their expression with each other, and characterize the presence of CD3+ T-lymphocytes in studied tumors and determine whether their presence correlates with FasL or survivin expression in malignant cases. FasL and survivin expression was assessed in 54 ovarian epithelial tumors. The results were compared between different tumor types and grades. Correlation between both markers' expression in all studied tumors was done. Either marker's expression was compared to the mean CD3+ T-lymphocytes per HPF in the studied malignant tumors. Either FasL or survivin expression was significantly higher in malignant versus benign ovarian epithelial tumors (p < 0.001 for both) and both markers were strongly correlated to each other (r = 0.877 & p < 0.001). Malignant tumors show significantly higher mean CD3+ T-lymphocytes than benign and borderline tumors. The mean CD3+ T-lymphocytes decrease significantly on increasing malignant tumor grade (p = 0.019) and expression of both FasL and survivin (r = -0.729, -0.582, respectively & p < 0.001 for both). The higher expression of FasL and survivin in malignant as compared to benign ovarian tumors suggest that they have a significant role in pathogenesis of ovarian carcinoma. Both markers are strongly correlated to each other and may contribute to immune escape of ovarian carcinoma as their higher expression is associated with decreased number of CD3 + T-lymphocytes.

The impact of T-cell immunity on ovarian cancer outcomes

Ovarian cancer remains a challenging disease for which improved treatments are urgently needed. Most patients present with advanced disease that is highly responsive to surgery combined with platinum- and taxane-based chemotherapy, with a state of minimal residual disease being achieved in many cases. However, chemotherapy-resistant recurrent tumors typically appear within 1-5 years and are ultimately fatal. Recently, several groups have shown that ovarian tumors are often infiltrated by activated T cells at the time of diagnosis, and patients with dense infiltrates of CD3+CD8+ T cells experience unexpectedly favorable progression-free and overall survival. Other cell types in the immune infiltrate oppose anti-tumor immunity, including CD4+CD25+FoxP3+ regulatory T cells, CD8+ regulatory T cells, macrophages, and dendritic cells. The composition of immune infiltrates is shaped by the expression of cytokines, chemokines, antigens, major histocompatibility complex molecules, and costimulatory molecules. The relationship between these various immunological factors is reviewed here with a strong emphasis on outcomes data so as to create a knowledge base that is well grounded in clinical reality. With improved understanding of the functional properties of natural CD8+ T-cell responses to ovarian cancer, there is great potential to improve clinical outcomes by amplifying host immunity.

Tumor-infiltrating T cells correlate with NY-ESO-1-specific autoantibodies in ovarian cancer

Background

Tumor-infiltrating CD8+ T cells are correlated with prolonged progression-free and overall survival in epithelial ovarian cancer (EOC). A significant fraction of EOC patients mount autoantibody responses to various tumor antigens, however the relationship between autoantibodies and tumor-infiltrating T cells has not been investigated in EOC or any other human cancer. We hypothesized that autoantibody and T cell responses may be correlated in EOC and directed toward the same antigens.

Methodology and Principal Findings

We obtained matched serum and tumor tissue from 35 patients with high-grade serous ovarian cancer. Serum samples were assessed by ELISA for autoantibodies to the common tumor antigen NY-ESO-1. Tumor tissue was examined by immunohistochemistry for expression of NY-ESO-1, various T cell markers (CD3, CD4, CD8, CD25, FoxP3, TIA-1 and Granzyme B) and other immunological markers (CD20, MHC class I and MHC class II). Lymphocytic infiltrates varied widely among tumors and included cells positive for CD3, CD8, TIA-1, CD25, FoxP3 and CD4. Twenty-six percent (9/35) of patients demonstrated serum IgG autoantibodies to NY-ESO-1, which were positively correlated with expression of NY-ESO-1 antigen by tumor cells (r = 0.57, p = 0.0004). Autoantibodies to NY-ESO-1 were associated with increased tumor-infiltrating CD8+, CD4+ and FoxP3+ cells. In an individual HLA-A2+ patient with autoantibodies to NY-ESO-1, CD8+ T cells isolated from solid tumor and ascites were reactive to NY-ESO-1 by IFN-γ ELISPOT and MHC class I pentamer staining.

Conclusion and Significance

We demonstrate that tumor-specific autoantibodies and tumor-infiltrating T cells are correlated in human cancer and can be directed against the same target antigen. This implies that autoantibodies may collaborate with tumor-infiltrating T cells to influence clinical outcomes in EOC. Furthermore, serological screening methods may prove useful for identifying clinically relevant T cell antigens for immunotherapy.

Prognostic significance of CD3+ tumor-infiltrating lymphocytes in ovarian carcinoma

OBJECTIVE

Epithelial ovarian cancer (EOC) is the most common cause of death among gynecological malignancies in Europe and North America. Although the presence of tumor-infiltrating mononuclear cells has been documented in EOC, the association of tumor-infiltrating mononuclear cells with clinical outcome remains controversial. The aim of the present study was to investigate the prognostic significance of CD3+ tumor-infiltrating T lymphocytes (TIL) on overall survival of EOC patients.

METHODS

We evaluated retrospectively by immunohistochemistry the distribution of CD3+ TIL in tumor specimens of 116 EOC patients. The expression of estrogen and progesterone receptors, Ki-67, DNA topoisomerase IIalpha, p21, p53, HER-2/neu, bax and bcl-2 was also evaluated by immunohistochemistry. The prognostic significance of CD3+ TIL and other immunohistochemical and clinical parameters was evaluated with log-rank test. Multivariate analysis was performed using the Cox regression.

RESULTS

CD3+ TIL were observed in all tumor samples, both in cancer stroma and within cancer epithelium (intraepithelial TIL). The median counts of stromal TIL and intraepithelial TIL were 338 lymphocytes/mm2 (range 81-2094 lymphocytes/mm2) and 125 lymphocytes/mm2 (range 7-481 lymphocytes/mm2), respectively. In univariate analysis, age, stage, grade, presence of residual tumor, expression of progesterone receptors, Ki-67, DNA topoisomerase IIalpha and intraepithelial CD3+ TIL count were significant predictors of overall survival. On multivariate analysis, only the presence of residual tumor, stage, expression of progesterone receptors and intraepithelial CD3+ TIL count were found to be significant independent predictors of overall survival.

CONCLUSION

Present data indicate that the intraepithelial CD3+ TIL count is a significant prognostic factor in EOC.