Bone alkaline phosphatase, osteocalcin and insulin-like growth factor-1 and their relationship in elderly women with advanced breast cancer and bone metastases

Objectives: Although breast cancer (BC) primarily metastasized to the regional lymph nodes, distant metastases, including lung, liver, brain and bone metastases (BMs) may also develop. The diagnostic value of serum bone tumor markers (TMs) in patients with BMs is still unclear. Unfortunately, it seems that there are not reliable TMs to be recommended during follow-up of patients with BC. The aim of this study was to evaluate the relationship between bone alkaline phosphatase (BAP), osteocalcin, and insulin-like growth factor (IGF)-1 in a small group of patients with BC and BMs. Methods: The medical records of 15 elderly (older than 65 years) women (median age 69 years, range 66-74 years) with advanced BC and BMs (confirmed with 18F-FDG-PET) were retrospectively reviewed. All patients have undergone regular measurement of several serum TMs, including BAP, osteocalcin, and IGF-1. The assay methods were automated spectrophotometric immunoassay, sandwich chemiluminescence immunoassay (CLIA), and sandwich (quantitative) colorimetric enzyme-linked immunosorbent assay (ELISA), respectively. Results: There was no correlation between the age of the patients and BAP (r=0.429, p=0.097), IGF-1 (r=0.369, p=0.158), and osteocalcin (r=0.520, p=0.038). The regression line equation between BAP and IGF-1 and osteocalcin were BAP=97.365476377746 + 1.62188663415666IGF-1 (r= 0.579, p=0.017), and BAP=121.34976066144 + 0.93059181897302osteocalcin (r=0.547, p=0.018), respectively. Conclusions: In women with advanced BC and BMs, all the three TMs considered were partially independent of one another. However, BAP was significantly (p<0.05) related to both IGF-1 and osteocalcin, suggesting that this TM is not useful in the early diagnosis of BMs. However, our results should be confirmed by further studies with more patients.