(ChemotherapyAdvisor) – Biomarker investigations in patients with breast cancer relapse may potentially improve patient management and survival, according to an international team of researchers. This conclusion is based on a study entitled “Clinically Used Breast Cancer Markers Such As Estrogen Receptor, Progesterone Receptor, and Human Epidermal Growth Factor Receptor 2 are Unstable throughout Tumor Progression,” which is published in the July 20 issue of the Journal of Clinical Oncology.
The investigators aimed “to investigate whether hormonal receptors and human epidermal growth factor receptor 2 (HER2) change throughout tumor progression, because this may alter patient management.” To meet this aim, biochemical or immunohistochemical (IHC)/ immunocytochemical (ICC) methods were used to determine the expression patterns of estrogen receptor (ER), progesterone receptor (PR), and HER2. These patterns were then confirmed by fluorescent in situ hybridization.
The following results were reported. Comparisons between expression patterns for ER, PR, and HER2 from both primary tumor and relapse tumor revealed a change in 32.4% (P<.001), 40.7% (P<.001), and 14.5% (P=.44) of patients, respectively. When the investigators assessed expression patterns of ER, PR, and HER2 in patients with multiple (from 2 to 6) consecutive relapses, they reported an alteration in 33.6%, 32.0%, and 15.7% of patients, respectively. More importantly, the investigators reported “a statistically significant differential overall survival related to intra-individual ER and PR status in primary tumor and relapse (P<.001).”
Finally, it was concluded that “patients with breast cancer experience altered hormone receptor and HER2 status throughout tumor progression, possibly influenced by adjuvant therapies, which significantly influences survival.”