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Single-nucleotide polymorphisms (SNP) associated with polygenetic disorders, such as breast cancer (BC), can create, destroy, or modify microRNA (miRNA) binding sites; however, the extent to which SNPs interfere with miRNA gene regulation and affect cancer susceptibility remains largely unknown. We hypothesize that disruption of miRNA target binding by SNPs is a widespread mechanism relevant to cancer susceptibility. To test this, we analyzed SNPs known to be associated with BC risk, in silico and in vitro, for their ability to modify miRNA binding sites and miRNA gene regulation and referred to these as target SNPs. We identified rs1982073-TGFB1 and rs1799782-XRCC1 as target SNPs, whose alleles could modulate gene expression by differential interaction with miR-187 and miR-138, respectively. Genome-wide bioinformatics analysis predicted approximately 64% of transcribed SNPs as target SNPs that can modify (increase/decrease) the binding energy of putative miRNA::mRNA duplexes by >90%. To assess whether target SNPs are implicated in BC susceptibility, we conducted a case-control population study and observed that germline occurrence of rs799917-BRCA1 and rs334348-TGFR1 significantly varies among populations with different risks of developing BC. Luciferase activity of target SNPs, allelic variants, and protein levels in cancer cell lines with different genotypes showed differential regulation of target genes following overexpression of the two interacting miRNAs (miR-638 and miR-628-5p). Therefore, we propose that transcribed target SNPs alter miRNA gene regulation and, consequently, protein expression, contributing to the likelihood of cancer susceptibility, by a novel mechanism of subtle gene regulation.

Background: Germline disease-causing mutations in BRCA1 and BRCA2 genes confer high risk of breast and ovarian cancer, but account approximately for only 15% of familial cases. Theoretical models and experimental observations have indicated that the remaining familial aggregations would be explained by low-penetrance alleles. Moreover, alleles acting as genetic modifiers would modulate the breast cancer risk in carriers of BRCA mutations. The Ins16bp and Arg72Pro polymorphisms of p53 were implicated in breast cancer and recently it has been shown that these polymorphisms could have an effect when combined as specific haplotypes. Here, we investigated the possible role of the Ins16bp and Arg72Pro polymorphisms and their haplotypes as low-penetrance alleles in familial breast cancer., Methods: The Ins16bp and Arg72Pro polymorphisms were genotyped in a total of 350 familial index cases affected with breast cancer and negative for mutations in BRCA genes, and 352 controls. The Ins16bp and Arg72Pro polymorphisms were studied separately, and as haplotypes and haplotypes combinations., Results: None of the performed analyses resulted statistically significant., Conclusions: These observations suggested that neither the Ins16bp or Arg72Pro polymorphisms considered separately, nor any related haplotype, were associated with breast cancer risk in BRCA-mutation negative familial cases.

A functional Gly388Arg variation in the FGFR4 gene has been reported to be associated with breast and colorectal cancer prognostic parameters. To further examine the functional role of this genetic polymorphism at the population level, we assessed the presence of the Arg388 allele in 142 breast carcinoma patients, 179 colorectal carcinoma patients and 220 general population controls with respect to an association with cancer prognosis and/or risk. No significant association with cancer risk, survival or any other prognostic parameters was observed in either breast or colorectal cancer. A pooled analysis of the present and published data on nodal status by FGFR4 genotypes revealed no association in either breast cancer [odds ratio (OR), 1.0; 95% confidence interval (CI), 0.7-1.4; 702 subjects] or colorectal cancer (OR, 1.4; 95% CI, 0.6-3.4; 260 cases). Thus, the FGFR4 polymorphism may not be relevant in predicting nodal involvement of breast cancer or colon cancer patients.

Purpose: We compared hematologic and clinical effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) after treatment with high-dose cyclophosphamide (HD-CTX, 7 g/m2), given as the first phase of a high-dose sequential chemotherapy program that includes a myeloablative therapy with mobilized progenitor cell autografting., Patients and Methods: Forty-nine consecutive patients with non-Hodgkin's lymphoma, Hodgkin's disease, or poor-prognosis breast cancer received GM-CSF (n = 27) or G-CSF (n = 22) after HD-CTX in two consecutive, nonrandomized studies. Cytokines were administered in continuous intravenous (i.v.) infusion for 14 to 15 days at a median dose of 5.5 and 10 micrograms/kg/d, respectively, starting 24 hours after HD-CTX., Results: Neutrophil recovery was faster with G-CSF administration (11.5 v 13.2 days; P = .01), whereas platelet counts recovered more rapidly with GM-CSF (13.7 v 16.6 days; P = .01). Prophylactic platelet transfusions were administered more frequently to patients treated with G-CSF than with GM-CSF (66% v 22% of the patients; P = .02). No clinically significant difference was observed between the two groups concerning days of absolute neutropenia or neutropenic fever. Both cytokines reduced the time to eligibility for subsequent chemotherapy administration compared with historical controls not given cytokine (14 to 16 v 20 days). Both cytokines increased circulation of hematopoietic progenitors. Most side effects were World Health Organization (WHO) median grade 1 to 2, were more frequent during GM-CSF than during G-CSF treatment, and were reversible by simple supportive measures and/or by dose reduction or suspension of the cytokine. Permanent suspension of cytokine administration was never required in either group., Conclusion: GM-CSF or G-CSF administration after HD-CTX reduces hematologic toxicity of high-dose chemotherapy and induces circulation of large amounts of hematopoietic progenitors suitable for autografting in cancer patients.

Seventy-seven (68 operable breast cancer with > 9 metastatic axillary nodes and 9 inflammatory breast cancer) entered this study. During hematopoietic recovery after cancer therapy with high-dose cyclophosphamide (7 g/m2; HD-CTX) circulating hematopoietic progenitors were collected by leukapheresis (LK) in all patients and then cryopreserved for autologous transplantation. Following HD-CTX, 70 patients were treated with hematopoietic growth factor(s) for 14 days: 38 with rhGM-CSF (group a), 16 with rhIL-3 (group b), 11 with sequential rhIL-3 and rhGM-CSF (group c), 5 with sequential rhIL-3 and rhG-CSF (group d). Seven control patients (group e) did not receive any growth factor. Leukaphereses, carried out over 2-4 consecutive days per patient, were started earlier in group c and in group d patients (mean day: +12 after HD-CTX). The sequential administration of rhIL-3 and rhG-CSF (group d) resulted in clearly higher yield of CFU-GM and CD34+ cells per leukapheresis (65.9 x 10(4)/Kg versus 20.9 x 10(6)/Kg, respectively) if compared with other groups of treatment.

Background: Interleukin-3, a recombinant cytokine with multilineage stimulatory effect on hematopoietic cells, was administered to 22 previously untreated breast cancer patients following high-dose therapy with cyclophosphamide (7 g/m2)., Patients and Methods: The growth factor, administered through continuous intravenous infusion at 1 (3 patients), 2.5 (3 patients), 5 (10 patients) and 10 micrograms/kg/day (6 patients), was well tolerated up to 5 micrograms/kg/day., Results: Nausea, vomiting, fever and headache prevented administration of the intended dose to all 6 patients in the 10 micrograms/kg/day cohort. At the maximal tolerable dose (5 micrograms/kg/day) the growth factor significantly accelerated granulocyte, platelet and reticulocyte recovery as compared to matched historical controls who received high-dose cyclophosphamide without cytokine infusion. Moreover, no platelet transfusions and fewer erythrocyte transfusions were required in interleukin 3-treated patients. In contrast to GM-CSF and G-CSF, interleukin 3 showed no effect on the mobilization of hematopoietic progenitor cells in the peripheral blood., Conclusions: Interleukin-3 represents a well-tolerated cytokine, clinically useful for accelerating trilineage hematopoietic recovery following severely myelotoxic treatments such as high-dose cyclophosphamide.

Antigen CD34+ cells represent 1-4% of adult bone marrow cells comprising virtually all hematopoietic colony-forming progenitors in-vitro and probably also stem cells capable of restoring hematopoiesis of lethally irradiated hosts. We report that sizable numbers of CD34+ cells transiently circulate in the peripheral blood (PB) of patients treated with high-dose (7 g/sqm) cyclophosphamide (HD-CTX) with or without recombinant human glycosylated granulocyte macrophage colony stimulating factor (rhGM-CSF). Evidence is presented demonstrating that CD34+ cells from PB possess qualitatively normal hematopoietic colony growth and high cloning efficiency similarly to marrow CD34+ cells. In addition, CD34+ cells from PB are shown to display heterogeneous flow cytometry characteristics and differentiation antigens analogous to those from bone marrow, i.e., CD34+/CD33-, CD34+/CD13-, CD34+/CD38-, CD34+/CD11b, CD34+/DRlow+ cells have light scatter properties of small lymphocytes while CD34+/CD33+, CD34+/CD13+, CD34+/CD38+, CD34+/CD11b+, CD34+/DRhigh+ cells have light scatter properties of blast-like cells. In HD-CTX treated patients, CD34+ cell circulation is 5-fold enhanced by rhGM-CSF 5.5 micrograms/kg/day by continuous iv infusion for 14 days. During the second-third week after HD-CTX, large-scale collection of PB leukocytes by 3-4 continuous-flow leukaphereses allows the yield of 2.19-2.73 x 10(9) or 0.45-0.56 x 10(9) CD34+ cells, depending on whether or not patients receive rhGM-CSF. The number of CD34+ cells retrieved from PB by leukaphereses exceeds the number that can be harvested by multiple bone marrow aspirations under general anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Seventeen patients with breast cancer (nine patients with 10 ipsilateral metastatic axillary nodes, eight patients with inflammatory breast carcinoma) previously untreated with cytotoxic chemotherapy received high-dose cyclophosphamide, 7 g/sqm (HD-CTX) as initial step of a high-dose sequential chemotherapy program. Eleven patients received also intravenous recombinant human granulocyte macrophage-colony stimulating factor (GM-CSF), 5.5 micrograms/kg per day for 7-14 days after HD-CTX. This growth factor significantly ameliorated leukopenia and thrombocytopenia induced by HD-CTX therapy thus allowing earlier delivery of subsequent courses of chemotherapy.