Clin Cancer Res
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Administration of growth factors prior to chemotherapy (priming) may reduce myelosuppression and provide an alternative to the use of stem cell support for the delivery of dose-intensive therapy. It is possible, however, that such priming may worsen aplasia, either by recruitment of progenitors into cell cycle and thereby increasing their sensitivity to chemotherapy or by depleting stem cell pools. We performed a Phase I/II trial of sequential interleukin 3 (IL-3)/granulocyte colony-stimulating factor (G-CSF) prior to and following high-dose etoposide and cyclophosphamide to determine the safety and efficacy of priming. ⋯ Hematological recovery of study patients was compared to that of an unprimed historical control group (n = 38) treated with the same chemotherapy followed by G-CSF alone. Neutrophil recovery to 500 and 1000/microliter and platelet recovery to >/=50,000/microliter was significantly faster in the study group compared to that of historical controls (P = 0.03, 0.05, and 0.01, respectively). Sequential IL-3/G-CSF given prior to and following high-dose etoposide and cyclophosphamide is safe and is a feasible strategy to compare in prospective randomized trials to patients treated with only postchemotherapy IL-3 and G-CSF and to patients treated with peripheral blood stem cell support.
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Overexpression of p185(c-erbB2) (p185/NEU/HER2) by tumor cells is associated with a poor prognosis in many but not all studies of breast and ovarian cancer. The poor prognosis associated with overexpression of p185(c-erbB2) could result from an increased growth rate or increased invasive potential. The p185(c-erbB2) tyrosine kinase receptor can be activated with agonistic antibodies directed against p185(c-erbB2) or with the ligand heregulin through a combinatorial interaction with erbB3 or erbB4. ⋯ Despite the similarity of effects of ID5 and heregulin on some outcomes, the ID5 antibody failed to increase adhesion to plastic, expression of CD54, or production of matrix metalloproteinase 9. Thus, the ID5 agonistic anti-p185(c-erbB2) antibody mimics rather than antagonizes some but not all of the actions of heregulin. Moreover, the poor prognosis of breast and ovarian cancers that overexpress p185(c-erbB2) could relate in part to enhanced invasiveness rather than to increased proliferative capacity.
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Comparative Study
Expression of epidermal growth factor receptor and c-erbB2 during the development of tamoxifen resistance in human breast cancer.
Expression of epidermal growth factor receptor (EGFR) or of c-erbB2 in primary breast cancer has been shown to predict for a poor chance of subsequent response of recurrent/metastatic disease to endocrine therapy. To assess the role of these receptors in the development of tamoxifen resistance, we examined their expression immunohistochemically on paraffin-embedded sections from breast cancers from 155 patients whose disease was progressing on tamoxifen therapy. Patients were categorized into those who initially responded to therapy (n = 56), those who never responded (n = 39), and those who relapsed while on adjuvant therapy and may or may not have "responded" (n = 60). ⋯ At the time of disease progression compared to pretreatment, there was no significant change in expression of either receptor, irrespective of initial response. The inverse relationship between EGFR and estrogen receptor was maintained at relapse on tamoxifen. These data argue strongly against the acquired expression of these receptors during treatment playing a major role in the development of tamoxifen resistance in human breast cancer.