ABSTRACT
Background: As compared to endocrine responsive breast cancer bone is less frequent site of distant recurrence in triple-negative breast cancer (TNBC). A biomarker which predicts bone recurrence would allow a more personalized treatment approach with adjuvant bisphosphonates in TNBC. Here we hypothesised that tumour expression of androgen receptor (AR) is associated with bone recurrence in TNBC. Materials and methods: Patients with operable TNBC who were treated at the Institute of Oncology Ljubljana between 2005 and 2015 and developed distant recurrence were included into our study. Nuclear expression of AR in the tissue of primary tumours was determined immunohistochemically by using the Androgen Receptor (SP107) Rabbit Monoclonal Antibody. We applied a logistic regression model to test the association between expression of AR and development of bone metastases. The model was adjusted for selected known prognostic factors and possible confounders in TNBC, including the level of the stromal tumour-infiltrating lymphocytes (sTILs). Results: At recurrence 45 (45 %) out of 100 patients presented with bone metastases. Additionally, seven (7 %) developed bone metastases metachronously. AR was expressed in primary tumours of 35 (35 %) women and 19 (54.3 %) developed bone recurrence. In 25 (25 %) patients sTILs were absent. Neither the proportion of AR positive cancer cells (OR = 1.00; 95 % CI 0.96-1.03; p = 1.00) nor the intensity of AR positive reaction (OR = 0.71; 95 % CI 0.02-21.4; p = 1.00) were significantly associated with bone recurrence. However, women with at least mild level of the sTILs were at significantly lower risk for bone recurrence as compared to those without any sTILs (OR = 0.01; 95 % CI < 0.01-0.08; p = 0.01). Conclusions: Expression of AR is not significantly associated with the development of bone metastases in TNBC. However, patients with absent sTILs in their primary tumours are highly susceptible for recurrence in the bone and might particularly benefit from adjuvant bisphosphonates.
ABSTRACT
BACKGROUND: The aim of the study was to evaluate the independent prognostic role of PIK3CA activating mutations and an association between PIK3CA activating mutations and efficacy of adjuvant endocrine therapy (ET) in patients with operable invasive lobular carcinoma (ILC). PATIENTS AND METHODS: A single institution study of patients with early-stage ILC treated between 2003 and 2008 was performed. Clinicopathological parameters, systemic therapy exposure and outcomes (distant metastasis-free survival [DMFS] and overall survival [OS]) were collected based on presence or absence of PIK3CA activating mutation in the primary tumor determined using a quantitative polymerase chain reaction (PCR)-based assay. An association between PIK3CA mutation status and prognosis in all patient cohort was analyzed by Kaplan-Meier survival analysis, whereas an association between PIK3CA mutation and ET was analyzed in estrogen receptors (ER) and/or progesterone receptors (PR)-positive group of our patients by the Cox proportional hazards model. RESULTS: Median age at diagnosis of all patients was 62.8 years and median follow-up time was 10.8 years. Among 365 patients, PIK3CA activating mutations were identified in 45%. PIK3CA activating mutations were not associated with differential DMFS and OS (p = 0.36 and p = 0.42, respectively). In patients with PIK3CA mutation each year of tamoxifen (TAM) or aromatase inhibitor (AI) decreased the risk of death by 27% and 21% in comparison to no ET, respectively. The type and duration of ET did not have significant impact on DMFS, however longer duration of ET had a favourable impact on OS. CONCLUSIONS: PIK3CA activating mutations are not associated with an impact on DMFS and OS in early-stage ILC. Patients with PIK3CA mutation had a statistically significantly decreased risk of death irrespective of whether they received TAM or an AI.
