Predictive and Prognostic Biomarkers for Lung Cancer Bone Metastasis and Their Therapeutic Value

Lung cancer is the leading cause of cancer-related death worldwide. Bone metastasis, which usually accompanies severe skeletal-related events, is the most common site for tumor distant dissemination and detected in more than one-third of patients with advanced lung cancer. Biopsy and imaging play critical roles in the diagnosis of bone metastasis; however, these approaches are characterized by evident limitations. Recently, studies regarding potential biomarkers in the serum, urine, and tumor tissue, were performed to predict the bone metastases and prognosis in patients with lung cancer. In this review, we summarize the findings of recent clinical research studies on biomarkers detected in samples obtained from patients with lung cancer bone metastasis. These markers include the following: (1) bone resorption-associated markers, such as N-terminal telopeptide (NTx)/C-terminal telopeptide (CTx), C-terminal telopeptide of type I collagen (CTx-I), tartrate-resistant acid phosphatase isoform 5b (TRACP-5b), pyridinoline (PYD), and parathyroid hormone related peptide (PTHrP); (2) bone formation-associated markers, including total serum alkaline phosphatase (ALP)/bone specific alkaline phosphatase(BAP), osteopontin (OP), osteocalcin (OS), amino-terminal extension propeptide of type I procollagen/carboxy-terminal extension propeptide of type I procollagen (PICP/PINP); (3) signaling markers, including epidermal growth factor receptor/Kirsten rat sarcoma/anaplastic lymphoma kinase (EGFR/KRAS/ALK), receptor activator of nuclear factor κB ligand/receptor activator of nuclear factor κB/osteoprotegerin (RANKL/RANK/OPG), C-X-C motif chemokine ligand 12/C-X-C motif chemokine receptor 4 (CXCL12/CXCR4), complement component 5a receptor (C5AR); and (4) other potential markers, such as calcium sensing receptor (CASR), bone sialoprotein (BSP), bone morphogenetic protein 2 (BMP2), cytokeratin 19 fragment/carcinoembryonic antigen (CYFRA/CEA), tissue factor, cell-free DNA, long non-coding RNA, and microRNA. The prognostic value of these markers is also investigated. Furthermore, we listed some clinical trials targeting hotspot biomarkers in advanced lung cancer referring for their therapeutic effects.

Clinical value of serum bone resorption markers for predicting clinical outcomes after use of bone modifying agents in metastatic bone tumors: A prospective cohort study

Bone modifying agents (BMAs) have become a standard treatment to prevent skeletal-related events (SREs) in bone metastases (BMs). The aim of our study is to determine the clinical value of serum bone resorption markers for predicting clinical outcomes after using BMAs in patients with BM. Patients were enrolled between May 2013 and October 2017 at the Nagoya University Hospital, Japan. We prospectively observed changes in pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and tartrate-resistant acid phosphatase 5b (TRACP-5b) during treatment with BMAs. The relationship between serum markers before and after treatment and clinical outcomes such as progression of bone disease (BD), SREs and overall survival (OS) were evaluated. Pearson chi-square test and Kaplan-Meier product limit methods were used for analysis. Sixty-seven patients were analyzed. The primary tumor sites were 21 lung, 16 breast and 30 others. Forty and 27 patients were treated with Denosumab and Zoledronic acid, respectively. Progression of BDs, SREs and death were observed in 10, 16 and 31 cases, respectively. The median follow-up period after using BMAs was 12.3 (range 0.3-66.3) months. ICTP at 3-4 weeks was significantly correlated with increasing BD progression, SREs and death after treatment in both the whole and lung cancer cohorts. Base line ICTP and TRACP-5b were also associated with increasing BD progression in the whole cohort. Our study showed that early posttreatment ICTP is useful for predicting BD progression, SREs and OS after use of BMAs in patients with BM and even in patients with lung cancer BM.