Triple negative breast cancer (TNBC), accounting for 15-20% of all breast cancers, lacks estrogen receptors, progesterone receptors, and amplification or overexpression of Her-2. As such, these tumors are not responsive to hormonal or anti-Her2 therapies, and are usually treated with combinations of surgery, radiation, and chemotherapy. Although many triple negative tumors respond well to chemotherapy, patients generally have poorer prognosis, higher relapse rates with aggressive tumor growth, and high metastatic potential. More than 300 clinical trials are currently ongoing in TNBC (www.clinicaltrials.gov) evaluating various single agent and combination approaches with chemotherapy, targeted therapy, immunotherapy, and radiation therapy. Clinically, radiation therapy has been associated with decreased risk of locoregional recurrence and some instances of improved overall survival when compared to patients that did not receive radiation therapy.1, 2
Preclinically there are few options to test effects of clinically relevant radiation therapy approaches. Labcorp has a Small Animal Radiation Research Platform (SARRP; Xstrahl) in house and can provide a solution to this currently unmet preclinical need.
HCC70 Evaluation With Paclitaxel and Docetaxel
The HCC70 human TNBC cell line can be used to model this disease preclinically. This cell line grows well following subcutaneous implant in female NSG mice (Figure 1A). To determine which chemotherapy would be suitable for combination approaches we evaluated both paclitaxel and docetaxel. We observed a strong response to docetaxel and a more modest response to paclitaxel (Figure 1B) with minimal effects on body weight loss (Figure 1C). The response to paclitaxel was further verified in an additional study (data not shown).