Emerging Biomarkers and New Understanding of Traditional Markers in Personalized Therapy for Breast Cancer

Abstract

The era of personalized medicine is likely to see an escalation in the use of biomarkers to ensure breast cancer patients receive optimal treatment. A combination of prognostic and predictive biomarkers should enable better quantification of the residual risk faced by patients and indicate the potential value of additional treatment. Established biomarkers such as estrogen receptor and progesterone receptor already play a significant role in the selection of patients for endocrine therapy. Human epidermal growth factor receptor 2 (HER2) is recognized as a strong predictor of response to trastuzumab whereas, more recently, the role of estrogen receptor and HER2 as negative and positive indicators for chemotherapy has also been explored. Ki67 has traditionally been recognized as a modest prognostic factor, but recent neoadjuvant studies suggest that on-treatment measurement may be a more effective predictor of treatment efficacy for both endocrine treatment and chemotherapy.The last decade has seen the emergence of numerous multigene expression profiles that aim to outdo traditional predictive and prognostic factors. The Oncotype DX assay and the MammaPrint profile are currently undergoing prospective clinical trials to clearly define their role. Other gene expression^based assays also show potential but are yet to be tested clinically. Rigorous comparison of these emerging markers with current treatment selection criteria will be required to determine whether they offer significant benefit to justify their use.

Molecular markers associated with response to chemotherapy in gastro-entero-pancreatic neuroendocrine tumors

“…Ki-67 proliferation index was associated with a response to doxorubicin in the entire cohort of patients and along with p53 were negatively correlated with response to therapy in patients treated with systemic therapy alone. While Ki-67 has traditionally been recognized as a modest prognostic factor, recent neoadjuvant studies in breast cancer suggest that on-treatment measurement may be a more effective predictor of treatment efficacy for both endocrine treatment and chemotherapy (Dowsett & Dunbier 2008, Miglietta et al 2009). Using tissue arrays, we previously found a differential expression of MDR1 in metastatic versus nonmetastatic pancreatic GEP (PZ0.0003; Couvelard et al 2006).…”

Breast cancer

“…The aim is to offer treatment to those patients who require it and to avoid potentially toxic (and expensive) therapies in those who will not benefit. 4 This is being investigated in trials that allocate chemotherapy or endocrine treatment based on genetic profiling and clinicopathological factors. 8,9 Biological therapy and novel agents…”

Discordance of Estrogen & Progesterone Receptors After Neoadjuvant Chemotherapy in Breast Cancer- an Indian Study

“…One of the most important biological factors in breast cancer is hormone receptor (HR) [3]. Estrogen receptor (ER) and progesterone receptors (PR) are both predictive and prognostic markers [4]. Traditionally quantitative assay of ER/PR expression is done by immunohistochemistry (IHC).…”