Standardized evaluation of tumor-infiltrating lymphocytes in breast cancer: results of the ring studies of the international immuno-oncology biomarker working group

Abstract

Multiple independent studies have shown that tumor-infiltrating lymphocytes (TIL) are prognostic in breast cancer with potential relevance for response to immune-checkpoint inhibitor therapy. Although many groups are currently evaluating TIL, there is no standardized system for diagnostic applications. This study reports the results of two ring studies investigating TIL conducted by the International Working Group on Immuno-oncology Biomarkers. The study aim was to determine the intraclass correlation coefficient (ICC) for evaluation of TIL by different pathologists. A total of 120 slides were evaluated by a large group of pathologists with a web-based system in ring study 1 and a more advanced software-system in ring study 2 that included an integrated feedback with standardized reference images. The predefined aim for successful ring studies 1 and 2 was an ICC above 0.7 (lower limit of 95% confidence interval (CI)). In ring study 1 the prespecified endpoint was not reached (ICC: 0.70; 95% CI: 0.62-0.78). On the basis of an analysis of sources of variation, we developed a more advanced digital image evaluation system for ring study 2, which improved the ICC to 0.89 (95% CI: 0.85-0.92). The Fleiss' kappa value for <60 vs ≥60% TIL improved from 0.45 (ring study 1) to 0.63 in RS2 and the mean concordance improved from 88 to 92%. This large international standardization project shows that reproducible evaluation of TIL is feasible in breast cancer. This opens the way for standardized reporting of tumor immunological parameters in clinical studies and diagnostic practice. The software-guided image evaluation approach used in ring study 2 may be of value as a tool for evaluation of TIL in clinical trials and diagnostic practice. The experience gained from this approach might be applicable to the standardization of other diagnostic parameters in histopathology.

Dose-Response Association of CD8+ Tumor-Infiltrating Lymphocytes and Survival Time in High-Grade Serous Ovarian Cancer

“…We also propose that, similar to the breast cancer community, a practical and robust scoring system should be developed. 43 Additional issues requiring large-scale study which were not evaluated here include: utility of image analysis; evaluation of stromal CD8 + TILs; consistency across multiple tumor sites per patient; impact of neoadjuvant chemotherapy; 45–47 relationships between CD8 + TIL levels, HGSOC molecular subtypes, 48–50 common genetic variation, 51 and epidemiologic risk factors; 52 and evaluation of other lymphocyte subsets, such as CD4 + TILs, CD20 + TILs (B cells), tertiary lymphoid structures, and plasma cells. 10,12–14,53 Clinically, it will be important to test whether CD8 + TILs predict response to certain therapies including standard chemo- and immune therapy, as, for example, CD8 + TILs predict chemo-response in subtypes of breast cancer.…”

Expression of T-Lymphocyte Markers in Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer

“…Multicenter international ring studies by the international Immuno-oncology Biomarker Working Group demonstrated that reproducible evaluation of TILs using slides is feasible and the software-guided image evaluation is useful [24]. Recommendations by an international TILs working group described that it is still unknown whether RNA or protein classification of TILs shows better performance of prognostic or predictive value than slide morphology and that further evidence of detecting specific subpopulations by IHC is necessary [14].…”

Chemokine receptor engineering of T cells with CXCR2 improves homing towards subcutaneous human melanomas in xenograft mouse model

“…To this end, presence of tumor infiltrating lymphocytes (TILs) has been shown to correlate with better prognosis of several solid cancers including MM, 7 colon carcinoma, 8 ovarian cancer 9 and breast cancer. 10 This is supported by accumulating data linking response to immune therapy with a brisk infiltration of T cells in the tumor. 7 , 11 , 12 …”