The NF-κB Pathway Promotes Tamoxifen Tolerance and Disease Recurrence in Estrogen Receptor-Positive Breast Cancers

The purpose of this study was to identify critical pathways promoting survival of tamoxifen-tolerant, estrogen receptor α positive (ER+) breast cancer cells, which contribute to therapy resistance and disease recurrence. Gene expression profiling and pathway analysis were performed in ER+ breast tumors of patients before and after neoadjuvant tamoxifen treatment and demonstrated activation of the NF-κB pathway and an enrichment of epithelial-to mesenchymal transition (EMT)/stemness features. Exposure of ER+ breast cancer cell lines to tamoxifen, in vitro and in vivo, gives rise to a tamoxifen-tolerant population with similar NF-κB activity and EMT/stemness characteristics. Small-molecule inhibitors and CRISPR/Cas9 knockout were used to assess the role of the NF-κB pathway and demonstrated that survival of tamoxifen-tolerant cells requires NF-κB activity. Moreover, this pathway was essential for tumor recurrence following tamoxifen withdrawal. These findings establish that elevated NF-κB activity is observed in breast cancer cell lines under selective pressure with tamoxifen in vitro and in vivo, as well as in patient tumors treated with neoadjuvant tamoxifen therapy. This pathway is essential for survival and regrowth of tamoxifen-tolerant cells, and, as such, NF-κB inhibition offers a promising approach to prevent recurrence of ER+ tumors following tamoxifen exposure. IMPLICATIONS: Understanding initial changes that enable survival of tamoxifen-tolerant cells, as mediated by NF-κB pathway, may translate into therapeutic interventions to prevent resistance and relapse, which remain major causes of breast cancer lethality.

Utilizing Tumor and Plasma Liquid Biopsy in Treatment Decision Making for an Estrogen Receptor-Positive Advanced Breast Cancer Patient

Breast cancer affects 12% of females in the United States and is the leading cause of cancer death in the female population. Personalized therapy is being used in clinical practice to treat breast cancer based on tumor molecular profiling, which can be obtained from tissue biopsy or plasma liquid biopsy as circulating tumor deoxyribonucleic acid (ctDNA). The available ctDNA tests provide a non-invasive way to monitor the cancer genome in a real-time manner.

In this case report, a 38-year-old female with recurrent estrogen receptor (ER) positive breast cancer is treated with letrozole, everolimus, and palbociclib. The drugs target the hormonal signaling pathway, phosphoinositide 3-kinase (PI3K)-RAC-alpha serine/threonine-protein kinase (AKT) pathway, and cyclin D1 (CCND1)-CDK4/6 pathway, based on the patient’s estrogen-receptor-positive (ER+) disease and phosphatidylinositol -4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) mutation, as well as PIK3CA and CCND1 amplification. After 11 months of treatment, retinoblastoma protein transcriptional corepressor 1 (RB1) mutation was caught in ctDNA, which suggests an acquired resistance to palbociclib. Pazopanib was then used instead of palbociclib, targeting the fibroblast growth factor 3/4/19 (FGF3/4/19) amplification that was initially observed in her molecular profiling. Trametinib was also suggested recently due to the increasing allele frequency of B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutation in ctDNA, following the treatment of letrozole + everolimus + pazopanib. The patient has no evidence of disease after five months of treatment initiation and has remained disease-free for over 16 months.

In conclusion, the analysis of ctDNA is an effective way to monitor the real-time changes in a patient's tumor genome, which is a great supplement to the molecular profile from the tissue biopsy. The combination of these two tests provides an efficient strategy to make more informed treatment decisions, which greatly adapt along disease development. 

Clinical nomogram to predict bone-only metastasis in patients with early breast carcinoma

BACKGROUND

Bone is one of the most common sites of distant metastasis in breast cancer. The purpose of this study was to combine selected clinical and pathologic variables to develop a nomogram that can predict the likelihood of bone-only metastasis (BOM) as the first site of recurrence in patients with early breast cancer.

METHODS

Medical records of patients with non-metastatic breast cancer were retrospectively collected. On the basis of the analysis of patient and tumour characteristics using the Cox proportional hazards regression model, a nomogram to predict BOM was constructed for a 4175-patient-training cohort. The nomogram was validated in an independent cohort of 579 patients.

RESULTS

Among 4175 patients with non-metastatic breast cancer, 314 developed subsequent BOM. Age, T classification, lymph node status, lymphovascular space invasion, and hormone receptor status were significantly and independently associated with subsequent BOM. The nomogram had a concordance index of 0.69 in the training set and 0.73 in the validation set.

CONCLUSIONS

We have developed a clinical nomogram to predict subsequent BOM in patients with non-metastatic breast cancer. Selection of a patient population at high risk for BOM could facilitate research of more specific staging approaches or the selective use of bone-targeted therapy.