Breast cancer is the most common female malignancy, affecting approximately one in eight women during their lifetime in North America and Europe. 0.05). To assess whether high progesterone and high RANKL indeed define a subgroup of women with increased risk of developing breast cancer, we classified all women – cases and controls considered together – into tertiles according to their serum progesterone levels. Within each group women were classified into low, medium or high RANKL, OPG and RANKL/OPG based on controls within the corresponding progesterone group. Using logistic regression women with high progesterone and high RANKL exhibited a 4.8 (95% CI 1.3 – free base inhibitor 22.8; = 0.0269) fold risk (Table ?(Table2).2). OPG levels alone did not modify the risk (Table ?(Table3).3). Importantly, women within the high progesterone and high serum RANKL/OPG ratio group carried a 5.3 (95% CI 1.5 – 25.4, = 0.0169) fold risk to develop breast cancer 12-24 months after diagnosis (Table ?(Table4).4). We also grouped the women into RANKL/OPG tertiles across all controls (not only within a given progesterone tertile) and again women within the high progesterone/high RANKL/OPG group experienced a 4.2 (95% CI 1.3 – 16.0, = 0.02) fold risk for developing breast cancer. Thus, high serum levels of RANKL and high serum progesterone stratify a subpopulation of postmenopausal women without known genetic predisposition at high risk of developing breast cancer 12-24 months before diagnosis. Table 2 Association of serum progesterone and RANKL with risk of breast malignancy (%)(%)OR (95% CI)?(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)OR (95% CI)?(%)(%)OR (95% CI)?(%)OR (95% CI)?of the local ER positive breast cancer and based on the numbers of CTCs. P values were calculated using the Mann Whitney U test. Abbreviations: CTC, circulating tumor cell; ER, estrogen receptor; OPG, osteoprotegerin; RANKL, Receptor Activator of NF-kB ligand. To test this hypothesis, we analysed serum RANKL/OPG in women with breast cancer diagnosis but free base inhibitor in the absence of a tumor in the breast – a similar scenario as in the UKCTOCS cohort close to breast cancer diagnosis. We analyzed 116 ER positive breast cancer patients from your SUCCESS trial after surgery and before systemic therapy (Table ?(Table5).5). Physique ?Physique3B3B demonstrates serum RANKL/OPG levels stratified to the number of circulating tumor cells (CTCs) identified in the corresponding blood sample [26, 27]. Intriguingly, women with a small number of CTCs (1-2 CTCs) exhibited a significantly reduced serum RANKL/OPG ratio compared to women without detectable CTCs (Physique ?(Figure3B).3B). Women with a 3-5 CTCs also exhibited reduced serum RANKL/OPG ratios, though this reduction did not reach statistical significance. Of notice, the serum RANKL/OPG ratio tends to increase again with an increase free base inhibitor in CTCs, albeit the numbers of cases is usually too small to allow for a firm conclusion. Thus, women with a very low quantity of CTCs in their blood exhibit a reduced RANKL/OPG ratio suggesting that this alterations we find up to one 12 free base inhibitor months in advance of a clinical breast cancer indeed correlate with low numbers of disseminated breast cancer cells. Table 5 Clinicopathological features of the 116 ER positive SUCCESS patients = 0.006; paired = 0.037; paired = 32; green lines) and women free of neoplastic disease during the 15 12 months follow-up (= 360; black lines). B. Box plots of RANKL-to-OPG ratios assessed prior to and after malignancy manifestation in women from your prospective Bruneck study indicate median ratio levels and inter-quartile ranges. In individuals who remained free of cancer, ratios given are those assessed at the time intervals corresponding to those in malignancy patients. Open in a separate window Physique 5 No changes in RANKL/OPG ratios in man that develop prostate malignancy or females with non-breast cancerA. Individual changes in serum levels of osteoprotegerin (OPG) and soluble (s) RANKL in 16 male subjects from our longitudinal Bruneck cohort before and after manifestations of prostate malignancy (dotted black lines). Mean changes are shown for subjects with incident prostate malignancy (reddish lines), other types of new-onset malignancy (= 57; green lines) and men free of neoplastic disease during the 15 12 months follow-up (= 337; black lines). B. Box plots of RANKL-to-OPG ratios show median ratio levels and inter-quartile ranges. Data were assessed prior to and after prostate malignancy manifestation, males with other types of new-onset malignancy and men free of neoplastic disease during the 15 12 months follow-up. For individuals who remained free of cancer, ratios given are those assessed at the time intervals corresponding to those in cancer patients. Conversation We and other groups have previously exhibited a central role for the osteoclastogenic molecule RANKL in breast IL4R cancer development using genetic mouse models [12C15]..