The clinical utility of baseline cardiac assessments prior to adjuvant anthracycline chemotherapy in breast cancer: a systematic review and meta-analysis.

BACKGROUND: Cardiac assessment with multi-gated acquisition scan (MUGA) or echocardiography (ECHO) is commonly employed prior to adjuvant anthracycline-based chemotherapy (AA). However, the clinical utility of routine baseline cardiac assessments prior to AA for early-stage breast cancer (EBC) is unknown. OBJECTIVES: To determine: (i) the clinical utility of routine baseline cardiac assessments prior to AA for EBC and (ii) identify patients in whom baseline cardiac assessments may not be warranted. METHODS: A systematic review of the literature was conducted to identify all relevant studies that met predefined criteria. The clinical utility was defined by: (i) the rates of abnormal baseline left ventricular ejection fraction (LVEF) and (ii) the rates of change in chemotherapy decisions prompted by baseline LVEF results. RESULTS: Eight studies met our criteria, of whom six (n = 2545) reported rates of abnormal LVEF and six (n = 1713) reported rates of change in chemotherapy decision. Overall, 2.5% (95% CI 2.0-4.0%) of patients had abnormal baseline LVEF and 1.6% (95% CI 1.0-3.0%) had a change in chemotherapy decision. In subset analyses, the underlying imaging modality (ECHO vs. MUGA) or inclusion of patients with metastatic disease (YES vs. NO) did not significantly affect these rates. There were no consistently identified underlying predictors of abnormal baseline LVEF across studies. CONCLUSIONS: Routine baseline cardiac assessments prior to AA in all EBC patients have low yield and infrequently affect clinical management. Future studies should further examine potential predictors of abnormal cardiac functions in an attempt to identify low risk patients in whom routine baseline LVEF assessment may not be warranted and prevent delay in chemotherapy administration.

Breast Cancer Malignant Processes are Regulated by Pax-5 Through the Disruption of FAK Signaling Pathways.

The study of genetic factors regulating breast cancer malignancy is a top priority to mitigate the morbidity and mortality associated with this disease. One of these factors, Pax-5, modulates cancer aggressiveness through the regulation of various components of the epithelial to mesenchymal transitioning (EMT) process. We have previously reported that Pax-5 expression profiles in cancer tissues inversely correlate with those of the Focal Adhesion Kinase (FAK), a potent activator of breast cancer malignancy. In this study, we set out to elucidate the molecular and regulatory relationship between Pax-5 and FAK in breast cancer processes. Interestingly, we found that Pax-5 mediated suppression of breast cancer cell migration is dependent of FAK activity. Our mechanistic examination revealed that Pax-5 inhibits FAK expression and activation. We also demonstrate that Pax-5 is a potent modulator of FAK repressors (p53 and miR-135b) and activator (NFκB) which results in the overall suppression of FAK-mediated signaling cascades. Altogether, our findings bring more insight to the molecular triggers regulating phenotypic transitioning process and signaling cascades leading to breast cancer progression.

The Pax-5 gene: a pluripotent regulator of B-cell differentiation and cancer disease.

The Pax-5 oncogene encodes a potent transcription factor that plays a key role in B-cell development and cancerous processes. In normal B-lymphopoiesis, Pax-5 accomplishes a dual function by activating B-cell commitment genes while concomitantly repressing non-B-lineage genes. Given the pivotal importance of Pax-5-mediated processes in B-cell development, an aberrant regulation of Pax5 expression has consistently been associated with B-cell cancers, namely, lymphoma and lymphocytic leukemias. More recently, Pax-5 gene expression has been proposed to influence carcinogenic events in tissues of nonlymphoid origin by promoting cell growth and survival. However, in other cases, Pax-5 products have opposing effects on proliferative activity, thus redefining its generally accepted role as an oncogene in cancer. In this review, we attempt to summarize recent findings about the function and regulation of Pax-5 gene products in B-cell development and related cancers. In addition, we present new findings that highlight the pleiotropic effects of Pax-5 activity in a number of other cancer types.

Coordinated expression of Pax-5 and FAK1 in metastasis.

The Pax-5 gene encodes a B-cell-specific activator protein (BSAP) that plays a key role in B lymphocyte differentiation and embryogenesis. The deregulation of this transcription factor is also linked to B cell malignancies and recently to other cancers. More specifically, the downstream effects of Pax-5 promote cell-cell interactions and mediate the activation of adhesion genes which result in an epithelial phenotypic behavior of human carcinoma cells. To gain a better understanding of Pax-5-mediated gene regulation, we studied available gene expression data in depth and identified several Pax-5 downstream targets. Among these, we found that Pax-5 activity is consistently inversely correlated with the expression of Focal Adhesion Kinase 1 (FAK1). FAK1 is known to enhance migration of cancer cells and promote metastatic dissemination to distant sites. Further analysis looking at genome wide profiling of Pax-5 DNAbinding points to both direct and indirect regulation of FAK1 expression by Pax-5 and its downstream targets. These findings suggest a key role for Pax-5 in phenotypic transitioning during metastasis through the regulation of FAK1 activity.