ABSTRACT
BACKGROUND: Aromatase inhibitors (AIs) are central to the management of oestrogen receptor-positive breast cancer in the adjuvant and metastatic setting. Levels of circulating steroid hormones (SHs) were measured in patients established on AIs to investigate: the influence of body mass index (BMI) in both the adjuvant and metastatic setting; the class of AI utilized in the adjuvant setting (steroidal versus non-steroidal); and differences in SH levels between women treated adjuvantly and those receiving a second-line AI for locally advanced/metastatic disease. METHODS: Plasma levels of androstenedione, 5-androstene-3ß,17ß-diol, dehydroepiandrosterone, oestradiol and testosterone were measured by radioimmunoassay in women with breast cancer who were receiving AIs in either an adjuvant or a metastatic setting. Differences between mean SH levels by class of AI, BMI, and second-line versus adjuvant therapy were assessed. RESULTS: Sixty-four women were receiving AI therapy, 45 (70 per cent) in an adjuvant setting and 19 (30 per cent) were taking a second-line AI. There was no significant correlation between BMI and SH levels. However, BMI was significantly higher in the second-line AI cohort compared with the adjuvant cohort (29.8 versus 26.2 kg/m2 respectively; P = 0.026). In the adjuvant setting, patients receiving a steroidal AI had significantly higher levels of all five hormones (P < 0.050). In the second-line AI cohort, oestradiol levels were significantly higher than in the adjuvant cohort (4.5 versus 3.3 pg/ml respectively; P = 0.022). Multivariable analysis adjusted for BMI confirmed the higher residual oestradiol level in the second-line AI group (P = 0.063) and a significantly higher androstenedione level (P = 0.022). CONCLUSION: Residual levels of SH were not significantly influenced by BMI. However, the significant differences in residual SH levels between the second-line and adjuvant AI cohort is of relevance in the context of resistance to AI therapy, and warrants further investigation.
Subject(s)
Aromatase Inhibitors/therapeutic use , Body Mass Index , Breast Neoplasms/drug therapy , Neoplasms, Hormone-Dependent/drug therapy , Steroids/metabolism , Adult , Aged , Aged, 80 and over , Analysis of Variance , Breast Neoplasms/metabolism , Breast Neoplasms/physiopathology , Chemotherapy, Adjuvant , Female , Gonadal Hormones/metabolism , Humans , Middle Aged , Neoplasm Metastasis , Neoplasms, Hormone-Dependent/metabolism , Neoplasms, Hormone-Dependent/physiopathology , RadioimmunoassayABSTRACT
BACKGROUND: Endo180 (CD280; MRC2; uPARAP)-dependent collagen remodelling is dysregulated in primary tumours and bone metastasis. Here, we confirm the release and diagnostic accuracy of soluble Endo180 for diagnosing metastasis in breast cancer (BCa). METHODS: Endo180 was quantified in BCa cell conditioned medium and plasma from BCa patients stratified according to disease status and bisphosphonate treatment (n=88). All P-values are from two-sided tests. RESULTS: Endo180 is released by ectodomain shedding from the surface of MCF-7 and MDA-MB-231 BCa cell lines. Plasma Endo180 was significantly higher in recurrent/metastatic (1.71±0.87; n=59) vs early/localised (0.92±0.37; n=29) BCa (P<0.0001). True/false-positive rates for metastasis classification were: 85%/50% for the reference standard, CA 15-3 antigen (28 U ml(-1)); ≤97%/≥36% for Endo180; and ≤97%/≥32% for CA 15-3 antigen+Endo180. Bisphosphonate treatment was associated with reduced Endo180 levels in BCa patients with bone metastasis (P=0.011; n=42). True/false-positive rates in bisphosphonate-naive patients (n=57) were: 68%/45% for CA 15-3 antigen; ≤95%/≥20% for Endo180; and ≤92%/≥21% for CA 15-3 antigen+Endo180. CONCLUSION: Endo180 is a potential marker modulated by bisphosphonates in metastatic BCa.
