SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. Approximately, 246,660 new cases of invasive breast cancer will be diagnosed in 2016 and 40,450 women will die of the disease. Patients with early stage breast cancer often receive adjuvant chemotherapy. The Oncotype DX breast cancer assay, is a multigene genomic test that analyzes the activity of a group of 21 genes and is able to predict the risk of breast cancer recurrence and likelihood of benefit from systemic chemotherapy, following surgery, in women with early stage breast cancer. Chemotherapy recommendations for early stage, hormone receptor positive, HER negative breast cancer patients, are often made based on tumor size, grade, immunohistochemical markers such as Ki-67, nodal status and 21-gene Recurrence Score (RS) assay.
The West German Study Group (WSG) PlanB phase III trial, used Recurrence Score assay prospectively, to define a low risk subset of patients with node negative disease with high risk traditional parameters and patients with node positive disease (HR+, HER2 negative), who could be treated with adjuvant endocrine therapy alone, sparing chemotherapy. In this study, patients with a Recurrence Score of 11 or less were defined as having low risk for recurrence, even in those considered to have tumor with high risk features such as large tumor size, high tumor grade and lymph node involvement. Patients were considered to be at intermediate or high risk if they had a Recurrence Score of 12 or more and 25 or more, respectively. Gluz and colleagues had previously reported 3-year follow up results of a planned interim analysis of this study, and were able to show significant difference between tumor grade, Ki-67 and Oncotype DX Recurrence Score.
In this current analysis, the authors reported the 5-year Disease Free Survival (DFS) outcomes of this large prospective trial. This analysis included data from 3,198 patients with early stage hormone receptor positive or HER2 negative breast cancer. The median age was 56 years and 32.5% of the patients had grade 3 tumors and 41% of the patients had node positive disease. Patients with a Recurrence Score of 11 or less received hormonal therapy and adjuvant chemotherapy was omitted. The intermediate and high risk patients were randomized to receive six cycles of TAXOTERE® (Docetaxel)/CYTOXAN® (Cyclophosphamide) or four cycles of ELLENCE® (Epirubicin)/CYTOXAN® followed by four cycles of TAXOTERE®. The primary endpoint was Disease Free Survival (DFS) defined as invasive or noninvasive relapse.
It was noted that the 5-year DFS in the low risk group was 94%, 84% in the high risk group and 94% in the intermediate risk group (P<0.001). It should be noted that approximately 15% of the patients in the clinically determined intermediate or high risk group, with 0-3 lymph node involvement, fell in the low genomic risk group (Recurrence Score of 11 or less) and received hormonal therapy alone.
The authors concluded that West German Study Group (WSG) PlanB study is the first trial that has reported five year survival data using 21-gene Recurrence Score assay, which can identify patients with early breast cancer, who would benefit from hormonal therapy alone and could be spared chemotherapy. Based on these data, 21-gene Recurrence Score has stronger prognostic value compared to immunohistochemical studies such as Ki-67 and hormone-receptor expression and should therefore be routinely incorporated in clinical practice as a decision making tool for this patient population, in addition tumor size, grade and nodal status. Prospective WSG Phase III PlanB trial: Clinical outcome at 5 year follow up and impact of 21 Gene Recurrence Score result, central/local-pathological review of grade, ER, PR and Ki67 in HR+/HER2- high risk node-negative and –positive breast cancer. Gluz O, Nitz U, Christgen M, et al. Abstract 8LBA. Presented at: 10th European Breast Cancer Conference; March 9-11, 2016; Amsterdam.


Following binding of antigen to the B-Cell Receptor, kinases such as Syk (Spleen Tyrosine Kinase), Lyn (member of the Src family of protein tyrosine kinases) and BTK (Bruton's Tyrosine Kinase) are activated, with subsequent propagation through PI3K/Akt, MAPK, and NF-κB pathways. This results in B-cell activation and proliferation. PI3K (PhosphoInositide 3-Kinase) delta signaling, is hyperactive in B-cell malignancies and is important for the activation, proliferation, homing of malignant B cells in the lymphoid tissues and their survival. The delta isoform of PI3K enzyme is predominantly expressed in leukocytes. Targeting proteins in key pathways of B-cell biology has fundamentally changed the management and outcomes of CLL, over the past 5 years. IMBRUVICA® (Ibrutinib) is an oral, irreversible inhibitor of BTK and inhibits cell proliferation and promotes programmed cell death (Apoptosis) by blocking B-cell activation and signaling. ZYDELIG® (Idelalisib) is a highly selective oral inhibitor of the enzyme PI3K and specifically blocks the delta isoform of PI3K enzyme and its signaling pathway. The pro-survival (anti-apoptotic) protein BCL2, is over expressed by CLL cells and regulates clonal selection and cell survival. A new class of anticancer agents known as BH3-mimetic drugs are in development that mimic the activity of the physiologic antagonists of BCL2 and related proteins and promote apoptosis (programmed cell death).
