Intrinsic genetic characteristics determine tumor-modifying capacity of fibroblasts: matrix metalloproteinase-3 5A/5A genotype enhances breast cancer cell invasion

Background Stromal fibroblasts can contribute to tumor invasion through the release of matrix metalloproteinases (MMPs). Population studies have suggested that single nucleotide polymorphisms (SNPs) in MMP genes influence levels of expression and may be associated with breast cancer risk and with disease progression. This study directly examined the impact of MMP SNP genotype on the ability of host fibroblasts to promote tumor cell invasion. Methods Primary breast fibroblasts were isolated from patients with (n = 13) or without (n = 19) breast cancer, and their ability to promote breast cancer cell invasion was measured in in vitro invasion assays. Fibroblast invasion-promoting capacity (IPC) was analyzed in relation to donor type (tumor or non-tumor patient), MMP-1, MMP-3, and MMP-9 SNP genotype and MMP activity using independent samples t test and analysis of variance. All statistical tests were two-sided. Results Tumor-derived fibroblasts promoted higher levels of invasion than normal fibroblasts (p = 0.041). When IPC was related to genotype, higher levels of IPC were generated by tumor fibroblasts with the high-expressing MMP-3 5A/5A genotype compared with the 5A/6A and 6A/6A genotypes (p = 0.05 and 0.07, respectively), and this was associated with enhanced MMP-3 release. The functional importance of MMP-3 was demonstrated by enhanced invasion in the presence of recombinant MMP-3, whereas reduction occurred in the presence of a specific MMP-3 inhibitor. An inverse relationship was demonstrated between fibroblast IPC and the high-expressing MMP-1 genotype (p = 0.031), but no relationship was seen with MMP-9 SNP status. In contrast, normal fibroblasts showed no variation in IPC in relation to MMP genotype, with MMP-3 5A/5A fibroblasts exhibiting significantly lower levels of IPC than their tumor-derived counterparts (p = 0.04). Conclusion This study has shown that tumor-derived fibroblasts exhibit higher levels of IPC than normal fibroblasts and that the MMP-3 5A/5A genotype contributes to this through enhanced MMP-3 release. Despite a high-expressing genotype, normal fibroblasts do not exhibit higher IPC or enhanced MMP release. This suggests that more complex changes occur in tumor-derived fibroblasts, enabling full expression of the MMP SNP genotype and these possibly are epigenetic in nature. The results do suggest that, in women with breast cancer, a high-expressing MMP-3 genotype may promote tumor progression more effectively

Delayed prescribing of antibiotics increased duration of acute otitis media symptoms in children but reduced diarrhoea

DesignRandomised (unclear allocation concealment), unblinded, controlled trial with about 1 week of follow up.SettingGeneral practices in south west UK.Patients315 children aged 6 months to 10 years (59% >3 y) who had acute otalgia and otoscopic evidence of acute inflammation of the ear drum. Exclusion criteria were otoscopic appearances consistent with crying or fever alone (pink ear drum only), appearances more suggestive of OM with effusion and chronic suppurative OM, serious chronic disease, use of antibiotics for ear infections in the previous 2 weeks, previous complications, or if the child was too unwell to be left to wait and see. 285 children (90%) were included in the analysis.InterventionAll patients were prescribed amoxicillin syrup, 125 mg in 5 ml, 3 times daily, 100 ml in total, except for patients allergic to penicillin who were prescribed erythromycin, 125 mg in 5 ml, 4 times daily for 1 week. 164 children were allocated to delayed prescription of antibiotics. Their parents were asked to wait for 72 hours before considering using their prescription. If, after that time, their child still had substantial otalgia or fever or was not getting better, parents were instructed to then pick up the prescription from the office. Parents could, however, pick up the prescription before 72 hours. 151 children were allocated to immediate prescription of antibiotics.Main outcome measuresMain outcome was duration of symptoms (earache, ear discharge, night disturbance, and crying). Other outcomes included number of missed school days, daily episodes of distress, daily consumption of paracetamol (acetaminophen), daily pain scores, number of children who actually took antibiotics, and adverse effects. Data were obtained from daily diaries kept by parents.Main resultsAnalysis was by intention to treat. Children allocated to delayed antibiotics had more days of earache (mean difference [MD] 1.10 d, 95% CI 0.54 to 1.48), ear discharge (MD 0.66 d, CI 0.19 to 1.13), night disturbance (MD 0.72 d, 0.30 to 1.13), and crying (MD 0.69 d, CI 0.31 to 1.08), and higher daily paracetamol consumption (MD 0.52 spoonfuls, CI 0.26 to 0.79) than children allocated to immediate antibiotics. The groups did not differ for number of school days missed, daily episodes of distress, and daily pain scores. Fewer children allocated to delayed prescription actually took the antibiotics compared with children allocated to immediate prescription (table). Fewer children allocated to delayed prescription had diarrhoea (9% v 19%, p=0.02)