Abstract P2-08-07: Prognostic significance of immune checkpoint receptors in node-negative breast cancer

Background: Immune checkpoint blockade is increasingly discussed in breast cancer. We examined the prognostic significance of the immune checkpoint receptors cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) in node-negative breast cancer.

Methods: Microarray based gene-expression data for CTLA-4 (221331_x_at) and PD-1 (207634_at) were analysed in four previously published cohorts (Mainz, Rotterdam, Transbig, Yu) of node-negative breast cancer patients not treated with adjuvant therapy (n=824). A meta-analysis of previously published cohorts was performed using a random effects model. Prognostic significance of CTLA-4 as well as PD-1 for metastasis-free survival (MFS) was examined in the whole cohort and in different molecular subtypes: luminal (ER+/HER2-), basal-like (ER-/HER2-) and HER2+. Independent prognostic relevance was analysed using multivariate Cox regression.

Results: Higher RNA expression of CTLA-4 was related to better MFS in a meta-analysis of the whole cohort (HR 0.58, 95% CI 0.38-0.88, P=0.0102). Prognostic significance was most pronounced in the HER2+ positive molecular subtype (HR 0.23, 95% CI 0.08-0.65, P=0.0062) as compared to luminal (HR 0.68, 95% CI 0.39-1.18, P=0.1744) and basal-like (HR 0.53, 95% CI 0.25-1.15), P=0.1087) carcinomas of the breast. PD-1 RNA expression, however, was not associated with outcome in the whole cohort of patients (HR 0.88, 95% CI 0.32-2.43, P=0.1853). A trend for improved survival was noticed in basal-like breast cancer (HR 0.40, 95% CI 0.15-1.08, P=0.0701). Neither luminal (HR 0.81, 95% CI 0.28-2.36, P=0.2122) nor HER2+ (HR 0.85, 95% CI 0.27-2.68, P=0.7759) patients showed an association of PD-1 with MFS. CTLA-4 showed independent prognostic significance (HR 0.393, 95% CI 0.224-0.688, P=0.001) in multivariate analysis. In addition to CTLA-4, only histological grade of differentiation (HR 2.335, 95% CI 1.490-3.660, P<0.0001) and tumor size (HR 1.924, 95% CI 1.260-2.937, P=0.002), but neither PD-1 nor age nor HER2 status nor hormone receptor status retained an independent prognostic association with MFS.

Conclusions: The immune checkpoint receptor CTLA-4 has independent prognostic significance in node-negative breast cancer. Higher expression of CTLA-4 is associated with improved outcome. The prognostic impact of CTLA-4 differs between molecular subtypes and is most pronounced in HER2+ breast cancer.

Citation Format: Schmidt M, van de Sandt L, Heimes A-S, Battista M, Lebrecht A, Almstedt K, Hoffmann G, Rahnenführer J, Hengstler JG. Prognostic significance of immune checkpoint receptors in node-negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-08-07.

Abstract P2-10-13: CD4 positive tumor-infiltrating lymphocytes are associated with improved prognosis in node-negative breast cancer

Background: The prognostic significance of CD8 positive cytotoxic lymphocytes in breast cancer is well accepted. However, the role of CD4 positive lymphocytes is ambiguous. We examined the prognostic relevance of CD4 positive tumor-infiltrating lymphocytes in previously published node-negative breast cancer cohorts using RNA expression.

Methods: Microarray based gene-expression data for CD4 (203547_at) were analyzed in four previously published cohorts (Mainz, Rotterdam, Transbig, Yu) of node-negative breast cancer patients not treated with adjuvant therapy (n = 824). A meta-analysis of previously published cohorts was performed using a random effects model. Prognostic significance of CD4 on metastasis-free survival (MFS) was examined in the whole cohort and in different molecular subtypes (ER+/HER2−, ER−/HER2−, HER2+). Independent prognostic relevance was analyzed using multivariate Cox regression.

Results: Higher RNA expression of CD4 was related to better MFS in a meta-analysis of the whole cohort (HR 0.66, 95% CI 0.49–0.90, p = 0.0074). Prognostic significance was most pronounced in the HER2+ positive molecular subtype (HR 0.32, 95% CI 0.14–0.75, p = 0.0091) as compared to ER+/HER2− (HR 0.62, 95% CI 0.29–1.32, P>0.05) and ER−/HER2− (HR 0.61, 95% CI 0.28–1.35, P>0.05) carcinomas of the breast. CD4 showed independent prognostic significance (HR 0.60, 95% CI 0.37–0.96, p = 0.032) in multivariate analysis. In addition to CD4, only histological grade of differentiation (HR 2.43, 95% CI 1.50–3.94, P < 0.001) and tumor size (HR 1.87, 95% CI 1.19–2.94, p = 0.007), but not age, HER2 status or hormone receptor status retained an independent prognostic association with MFS.

Conclusion: CD4 positive tumor-infiltrating lymphocytes have independent prognostic significance in node-negative breast cancer. A higher expression is associated with improved outcome.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-13.