72PClinico-pathological relationship between androgen receptor (AR) and tumor infiltrating lymphocytes (TILs) in triple negative breast cancer (TNBC)

Background Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC) with ill-defined therapeutic targets. Androgen receptor (AR) and tumor-infiltrating lymphocytes (TILs) had a prognostic and predictive value in TNBC. The relationship between AR, TILs and clinical behavior is still not fully understood. Methods Thirty-six TNBC patients were evaluated for AR (positive if ≥ 1% expression), CD3, CD4, CD8 and CD20 by immunohistochemistry. Stromal TILs were quantified following TILs Working Group recommendations. Lymphocyte-predominant breast cancer (LPBC) was defined as having stromal TILs ≥ 50%, whereas lymphocyte-deficient breast cancer (LDBC) was defined as < 50%. Results The mean age was 52.5 years and 27.8% were ≥ 60 years. Seven patients (21.2%) were AR+. All AR + cases were postmenopausal (≥ 50 years old). No statistical difference was found in median overall survival (OS) between AR- and AR + groups (31.5 vs. 25 months, p = 0.77). LPBC was 32.2%. Median TILs was 37.5% and 10% (p = 0.1) and median CD20 was 20% and 7.5% (p = 0.008) in AR- and AR+, respectively. Mean CD3 was 80.7% and 93.3% (p = 0.007) and CD8 was 75% and 80.8% (p = 0.41) in AR- and AR + respectively. All patients who were ≥ 60 years old expressed CD20. LDBC was found to be significantly higher in N + vs. N- patients (p = 0.03) with median TILs of 20% vs. 50% in N + vs. N-, respectively (p = 0.03). LDBC was associated with higher risk of lymph node involvement (OR = 6, 95% CI = 1.05–34.21, p = 0.04). Conclusions AR expression was evident in older age (≥ 50 years). Median CD20 was higher in AR- TNBC, while mean CD3 was higher in AR + tumors. LDBC was associated with higher risk of lymph node involvement. Larger studies are needed to focus on the clinical impact of the relation between AR and TILs in TNBC.