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Abstract Background Many factors influence breast cancer progression, including the ability of progenitor cells to sustain or increase net tumour cell numbers. Our aim was to define whether alterations in putative progenitor populations could predict clinicopathological factors of prognostic importance for cancer progression. Methods Primary cultures were established from human breast tumour and adjacent non-tumour tissue. Putative progenitor cell populations were isolated based on co-expression or concomitant absence of the epithelial and myoepithelial markers EPCAM and CALLA respectively. Results Significant reductions in cellular senescence were observed in tumour versus non-tumour cultures, accompanied by a stepwise increase in proliferation:senescence ratios. A novel correlation between tumour aggressiveness and an imbalance of putative progenitor subpopulations was also observed. Specifically, an increased double-negative (DN) to double-positive (DP) ratio distinguished aggressive tumours of high grade, estrogen receptor-negativity or HER2-positivity. The DN:DP ratio was also higher in malignant MDA-MB-231 cells relative to non-tumourogenic MCF-10A cells. Ultrastructural analysis of the DN subpopulation in an invasive tumour culture revealed enrichment in lipofuscin bodies, markers of ageing or senescent cells. Conclusions Our results suggest that an imbalance in tumour progenitor subpopulations imbalances the functional relationship between proliferation and senescence, creating a microenvironment favouring tumour progression.

Background: Live animal studies using an inoculation model of breast cancer indicate that anaesthetic drugs and techniques differentially affect cancer metastasis, inversely related to Natural Killer (NK) cell and T lymphocyte levels. Clinical histological studies demonstrate that the distribution of these immune cells and macrophages in intra-tumoral cancer tissue can predict prognosis and response to therapy. No study has evaluated whether the anaesthetic technique influences human breast cancer immune cell infiltration., Materials and Methods: Excised breast cancer specimens from patients previously enrolled in an ongoing, prospective, randomised trial (NCT00418457) investigating the effect of anaesthetic technique on long-term breast cancer outcome were immunohistochemically stained to enable a colour deconvolution technique to summate marked immune cell infiltration: CD56 (NK cells), CD4 (T helper cells), CD8 (T suppressor cells) and CD68 (macrophages). Patients were randomised to receive either a propofol-paravertebral anaesthetic with continuing analgesia (PPA, n=12) or a balanced general anaesthesia with opioid analgesia (GA, n=16) for 24 h postoperatively. Investigators were masked to group allocation., Results: Normalised positive intensity values, (median (interquartile range (IQR)), for CD56 were lower in GA121 (116-134) versus 136 (132-142), p=0.015. CD4 was also lower in GA10.9 (5.5-27.8) versus PPA 19.7 (14.4-83.5), p=0.03 but CD8 5.5 (4.0-9.75) versus 13.0 (5.0-14.5) respectively, p=0.24 and CD 68 infiltration 5.8 (3.25-8.75) versus 8.0 (3.0-8.75), p=0.74 were not significantly different., Conclusion: PPA induces increased levels of NK and T helper cell infiltration into breast cancer tissue compared with GA but not T suppressor cells or macro phages. This is consistent with the hypothesis that the anaesthetic technique may affect perioperative immune function conducive to resisting breast cancer recurrence and metastasis., (Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)