Monitoring of Serum DNA Methylation as an Early Independent Marker of Response and Survival in Metastatic Breast Cancer: TBCRC 005 Prospective Biomarker Study

Epigenetic alterations measured in blood may help guide breast cancer treatment. The multisite prospective study TBCRC 005 was conducted to examine the ability of a novel panel of cell-free DNA methylation markers to predict survival outcomes in metastatic breast cancer (MBC) using a new quantitative multiplex assay (cMethDNA)

Fixed-dose capecitabine is feasible: results from a pharmacokinetic and pharmacogenetic study in metastatic breast cancer

The pro-drug capecitabine is approved for treatment of anthracycline- and paclitaxel-resistant metastatic breast cancer. However, toxicity and large interpatient pharmacokinetic variability occur despite body surface area (BSA)-dosing. We hypothesized that a fixed-dose schedule would simplify dosing and provide an effective and safe alternative to BSA-based dosing

Novel Methylated Biomarkers and a Robust Assay to Detect Circulating Tumor DNA in Metastatic Breast Cancer

The ability to consistently detect cell-free tumor-specific DNA in peripheral blood of patients with metastatic breast cancer provides the opportunity to detect changes in tumor burden and to monitor response to treatment. We developed cMethDNA, a quantitative multiplexed methylation-specific PCR assay for a panel of ten genes, consisting of novel and known breast cancer hypermethylated markers identified by mining our previously reported study of DNA methylation patterns in breast tissue (103 cancer, 21 normal on the Illumina HumanMethylation27 Beadchip) and then validating the 10-gene panel in a TCGA breast cancer methylome database. For cMethDNA, a fixed physiological level (50 copies) of artificially constructed, standard non-human reference DNA specific for each gene is introduced into in a constant volume of serum (300 μl) prior to purification of the DNA, facilitating a sensitive, specific, robust and quantitative assay of tumor DNA, with broad dynamic range. Cancer-specific methylated DNA was detected in Training (28 normal, 24 cancer) and Test (27 normal, 33 cancer) sets of recurrent Stage 4 patient sera with a sensitivity of 91% and a specificity of 96% in the test set. In a pilot study, cMethDNA assay faithfully reflected patient response to chemotherapy (N = 29). A core methylation signature present in the primary breast cancer was retained in serum and metastatic tissues collected at autopsy 2–11 years after diagnosis of the disease. Together, our data suggest that the cMethDNA assay can detect advanced breast cancer, and monitor tumor burden and treatment response in women with metastatic breast cancer

Changes in breast density and circulating estrogens in postmenopausal women receiving adjuvant anastrozole

Factors associated with an increased risk of breast cancer include prior breast cancer, high circulating estrogens, and increased breast density. Adjuvant aromatase inhibitors are associated with a reduction in incidence of contralateral breast cancer. We conducted a prospective, single-arm, single-institution study to determine whether use of anastrozole is associated with changes in contralateral breast density and circulating estrogens. Eligible patients included postmenopausal women with hormone receptor-positive early-stage breast cancer who had completed local therapy, had an intact contralateral breast, and were recommended an aromatase inhibitor as their only systemic therapy. Participants received anastrozole 1 mg daily for 12 months on study. We assessed contralateral breast density and serum estrogens at baseline, 6, and 12 months. The primary endpoint was change in contralateral percent breast density from baseline to 12 months. Secondary endpoints included change in serum estrone sulfate from baseline to 12 months. Fifty-four patients were accrued. At 12 months, compared with baseline, there was a nonstatistically significant reduction in breast density (mean change: -16%, 95% CI: -30 to 2, P = 0.08) and a significant reduction in estrone sulfate (mean change: -93%, 95% CI: -94 to -91, P < 0.001). Eighteen women achieved 20% or greater relative reduction in contralateral percent density at 12 months compared with baseline; however, no measured patient or disease characteristics distinguished these women from the overall population. Large trials are required to provide additional data on the relationship between aromatase inhibitors and breast density and, more importantly, whether observed changes in breast density correlate with meaningful disease-specific outcomes