Abstract PD5-09: Immune parameters associated with survival in triple negative and HER2-positive breast cancer patients with 10 years of follow-up

The clinical utility of tumor-infiltrating lymphocytes (TIL) is actively being investigated in breast cancer (BC). It is unclear whether TIL spatial location and organization in tertiary lymphoid structures (TLS) have an impact on prognosis. Additionally, the significance of PD-1 and PD-L1 expression is being debated due to conflicting data from several studies. We hypothesize that the presence, extent and spatial location of multiple immune biomarkers, reflecting ongoing immune responses, will be consistently associated with a good prognosis in highly infiltrated BC [triple-negative (TNBC) and HER2+].

The relationship between these immune biomarkers and clinical outcome was examined in the TNBC and HER2+ cohorts of node-positive BC patients enrolled in the BIG 02-98 adjuvant phase III trial with available material for immunohistochemical (IHC) labeling (N=113 and N=136, respectively). HER2+ patients did not receive trastuzumab. Dual IHC staining was performed on full-face consecutive tissue sections. Scoring was independently performed by two pathologists, blinded to the clinical data, and included: global, intratumoral and stromal TIL and TLS, assessed on CD3/CD20 slides; the percentage and location of PD-1 and PD-L1 expression, assessed on PD-1/PD-L1 slides. TIL were considered as a categorical variable with different cut-offs used for each parameter and for each cohort (TNBC and HER2+). Invasive disease-free survival (I-DFS) and overall survival (OS) were analyzed (median follow-up: 10 years). Cox proportional hazard models were used for survival analyses.

The TNBC cohort revealed an association between global TIL and outcome [adjusted hazard ratio (HR) for I-DFS: 0.27 (0.15-0.51); OS: 0.26 (0.13-0.53)]. Similar results were observed for stromal and intratumoral TIL. PD-L1 expression within TLS was an independent predictor of OS, after adjustment for tumor size and age [HR: 0.30 (0.09-0.99)]. Multivariate analysis reveals this effect was principally driven by high stromal TIL (>17.5% based on CD3/CD20 assessment) (χ2 OS: p=0.009). In contrast, no significant prognostic associations were found in the overall HER2+ cohort. However high T cell TIL were associated with improved I-DFS and OS in the ER-/HER2+ group [I-DFS: 0.34 (0.14-0.80); OS: 0.32 (0.12-0.86)] and stromal TIL were associated with improved I-DFS in the ER+/HER2+ group [HR: 0.29 (0.09-0.94)] (univariate analyses). No significant associations between the number of TLS nor the expression of PD-1 with outcomes were observed in either cohorts.

The presence of PD-L1+ TLS, driven by high baseline TIL, was associated with an excellent prognosis in node-positive TNBC. This observation might reflect specific immune activities taking place in these mini lymph node-like structures adjacent to the tumor bed where specific antitumor memory immune responses could be generated. No different prognostic impact was observed when analyzing TIL spatial location. Although the statistical power of the study might be limited, in line with previous findings our data reveal that, among the immune parameters evaluated, TIL are the strongest predictor of outcome in TNBC, while PD-L1+ TLS could be a new and important parameter that requires further investigation.

Citation Format: Solinas C, de Wind A, Van den Eynden G, Ameye L, Garaud S, De Silva P, Boisson A, Noel G, Langouo Fontsa M, Buisseret L, de Azambuja E, Francis PA, Di Leo A, Crown JP, Sotiriou C, Larsimont D, Paesmans M, Piccart-Gebhart M, Willard-Gallo K. Immune parameters associated with survival in triple negative and HER2-positive breast cancer patients with 10 years of follow-up [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD5-09.

[Diagnostic approach of an IgM monoclonal gammopathy and clinical importance of gene MYD88 L265P mutation]

INTRODUCTION

An IgM monoclonal gammopathy points to a diagnosis of Waldenstrom's Macroglobulinemia. Other B lymphoproliferatives disorders should be ruled out but the limits are sometimes difficult to define. The discovery of the L265P mutation of the MYD88 gene simplified potentially the situation.

POPULATION AND METHODS

383 patients of the Jules Bordet Institute with an IgM level above 2 g/L were reviewed. For the 49 who had a monoclonal peak, we analysed the underlying pathology in termes of general, clinical and biological characteristics. We checked if the MYD88 mutation had been detected. The overall survival rate was studied.

RESULTS

5 histological groups were identified: Waldenstrom's Macroglobulinemia (MW, N = 27), lymphoplasmacytic lymphoma (LLP, N = 10), marginal zone lymphoma (LMZ, N = 7), monoclonal gammopathy of unknown significance and multiple myeloma (MGUS/MM, N = 5). The MW group was compared to the other groups. Regarding biological characteristics, the IgM level upon diagnosis was statistically higher in the MW group with a median level at 19.5 g/L (2.3-101 g/L) (p-value = 0,0001). Concerning the clinical characteristics, a splenomegaly was more frequent in the LMZ group (p-value = 0,04). The L265P mutation of the MYD88 gene was found in 77 % of patients in the MW group, 60 % of patients in the LLP group and 67 % in the LMZ group (p-value = 0,38). For the 49 patients, the 10-yearoverall survival was 85 % (CI 95 %, 67 % to 94 %) and the 15-year-overall survival was 65 % (CI 95 %, 41 % to 81 %).

CONCLUSION

A monoclonal IgM peak suggests a MW but other B lymphoproliferatives disorders should be excluded. Even if the L265P mutation is frequent in the LLP/MW, it is not specific. A precise diagnosis requires collating clinical, histological, immunophenotypical and genetical data.

Abstract P2-04-04: BRCA gene mutations do not shape the extent and organization of tumor infiltrating lymphocytes in triple negative breast cancer

The remarkable responses observed in metastatic cancer patients treated with immunotherapies, including inhibitors directed to the PD-1 and PD-L1 checkpoint molecules, makes it a priority to identify critical variations in pro- and anti-tumor immune responses in breast cancer (BC). In patients with triple negative (TN) BC, an increased presence of tumor infiltrating lymphocytes (TIL) and tertiary lymphoid structures (TLS) have been associated with good clinical outcomes. However, the frequency of specific lymphocyte subpopulations, PD-1 and/or PD-L1 expression and their prognostic significance remains an open question. Our recent work found that PD-1 and PD-L1 expression are specifically associated with higher TIL densities and an increased number of TLS in BC. We further demonstrated that TIL density, TLS and PD-L1 expression were correlated with more aggressive breast tumor characteristics, including higher proliferation and hormone receptor negativity. In this project, we examined the prevalence of TIL, TLS, PD-1 and PD-L1 expression in TNBC and further compared these immune parameters between TNBC patients harboring BRCA1 or BRCA2 germline gene mutations with those carrying the wild-type (wt) genes.

A total of 1402 BC patients whose blood was genetically tested for germline BRCA1 and BRCA2 mutations were examined for inclusion in this study. Ninety-eight chemotherapy-naïve patients with primary invasive ER–, PR– and HER2– BC and demonstrated germline BRCA1 or BRCA2 wt or mutated-gene status were included in this study. Ninety-four tumors were determined to be suitable for evaluating immune cell infiltration (51 BRCA wt and 43 BRCA-mutated). FFPE tumor tissue from the surgical specimens was analyzed by immunohistochemistry (IHC) staining of full-face tissue sections. IHC was performed as a dual label using CD3 plus CD20 for T and B cells, CD4 plus CD8 for the major T cell subpopulations and PD-1 plus PD-L1 for individual or paired expression of these receptors. The stained slides were independently scored by two experienced pathologists for TIL, TIL subpopulations, TLS and checkpoint molecule expression.

These analyses revealed that 87% of our TNBC cohort was TIL-positive (≥10% TIL) with 35% classified as lymphocyte predominant BC (LPBC; ≥50% TIL). T cells were the principal component of the lymphocytic infiltrate with no significant differences between the BRCA wt and BRCA-mutated groups detected in total T cells (CD3+), helper T cells (CD4+), cytotoxic T cells (CD8+) or B cells (CD20+). TLS were identified in 73% of tumors with again no significant differences between the BRCA groups. Examination of checkpoint molecule expression identified 33% tumors as PD-1 positive and 40% as PD-L1 positive. PD-1 expression was correlated with PD-L1 expression and both with TIL positivity and the level of immune infiltration but not BRCA mutational status.

Overall, our analyses revealed that BRCA wt and BRCA-mutated TNBC are remarkably similar in terms of TIL heterogeneity, a TLS presence and checkpoint molecule expression. These data suggest that BRCA gene mutations are not immunogenic nor do they directly drive immune infiltration in TNBC.

Citation Format: Willard-Gallo K, Solinas C, Marcoux D, t'Kint de Roodenbeke D, Garaud S, Van den Eynden G, de Wind A, Boisson A, Larsimont D, Piccart M. BRCA gene mutations do not shape the extent and organization of tumor infiltrating lymphocytes in triple negative breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-04-04.

Abstract P5-01-02: Characterization of follicular helper CD4 T cells and B cells resident in peritumoral tertiary lymphocyte structures as specific markers for an immunological grade in breast cancer

Molecular approaches such as gene expression profiling have improved the classification of human breast cancer (BC) by identifying molecular subtypes and demonstrating that the immune infiltrate is an important prognostic or predictive factor. Our prospective study of freshly isolated CD4+ T cells infiltrating (TIL) BC discovered that along with Th1, Th2 and Th17 effector memory and Treg subpopulations the newest CD4+ Th subset, T follicular helper (Tfh) cells, was also present in the tumor. Comparison of extensive versus minimally-infiltrated tumors led to our finding that extensive immune infiltrates are distinguished by Tfh cells located in tertiary lymphoid structures (TLS) next to the tumor bed. TLS are highly organized with a CD3+ T cell zone adjacent to a CD20+ B cell follicle with germinal centers containing Bcl6+ Tfh cells, CD23+ follicular dendritic cells and Ki67+ cells. Tfh cells are known to play a critical role in generating antibody producing plasma cells and memory B cells. We demonstrated that Tfh cells are the principal cellular source of the B cell chemoattractant CXCL13 in BC. Thus, a Tfh presence paralleled the TLS incidence and together they were associated with an increased peritumoral B cell presence and a higher frequency of CD8+ T cells in the tumor bed. Our recent work shows that approximately 50% of the infiltrating B cells are memory cells in contrast to normal and non-tumor non-adjacent breast tissue (controls, less than 15%). A significant B cell presence is found in extensively infiltrated high proliferative BC subtypes with germinal center centroblasts and centrocytes consistently associated with a Tfh cell presence. We assessed immunoglobulin isotypes in supernatants of fresh breast tissue homogenates, detecting decreased IgA and increased IgG and IgM in the tumor tissue compared to controls. Patient sera, particularly from patients with high proliferative BC subtypes, had elevated IgG3 and IgG4 compared to low proliferative tumors and healthy donors. Immunofluorescent analysis found the majority of B cells infiltrating tumors have germinal center characteristics (IgD+Ki67+CD35+CD21+PD-1+) and are clustered with Tfh in the B cell follicles surrounded by a T cell zone, which together create the tumor-associated TLS. Based on their specificity for TLS, we derived a scoring system, referred to as immunological grade, to measure the extent of the lymphocytic infiltrate and the level of immune organization. This system is based on a morphological score (the density of the lymphocyte infiltrate determined by CD3/CD20 immunohistochemistry plus the number and size of peritumoral TLS assessed by two pathologists) together with a molecular score [an 8 gene qRT-PCR Tfh signature that predicts long term survival in an untreated patient cohort with >10-year survival (n = 794) or pathological complete response in patients treated with preoperative chemotherapy (n = 996)]. We are testing this immunological grading system on a large retrospective series of patients to determine its value in evaluating a patient's anti-tumor immune response in pre-operative biopsies and/or the primary tumor at surgery as a new marker for use in treatment decisions.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-01-02.

[Non Hodgkin's lymphomas: a major breakthrough with immunotherapy]

Non hodgkin's lymphomas are a group of haematological malignancies in which spectacular progress has been made over the last ten years thanks to immunotherapy. Furthermore, the new WHO classification, based upon tumour immunology, the degree of tumour differentiation and cytogenetic abnormalities, has finally improved identification of each lymphoma and has enabled comparison of homogeneous populations between different clinical studies. The increase in the incidence of non hodgkin's lymphoma is related to the aging of the population and to other factors that are yet to be elucidated--a real challenge for the future. We have tried to offer an overview of the latest therapeutic advances, with a focus on (radio-) immunotherapy and haemopoietic stem cell transplantation.