Tumor self-seeding by circulating tumor cells in nude mouse models of human osteosarcoma and a preliminary study of its mechanisms

PURPOSE

The purpose of this study is to determine whether and how tumor self-seeding by circulating tumor cells (CTCs) plays a role in the initiation and progression of osteosarcoma.

METHODS

Two different nude mouse models of human osteosarcoma were established for detecting tumor self-seeding by fluorescently labeled CTCs. Various tumor growth indicators were quantitated for seeded and unseeded groups. Growth mechanisms were characterized using cell proliferation assays and immunohistochemical staining. Conditioned media of primary osteosarcoma cells was characterized in a Transwell migration assay and enzyme-linked immunosorbent assay. The effect of cytokines secreted by primary tumor cells was verified by small interfering RNA and recombinant human cytokine experiments.

RESULTS

Red fluorescent protein-labeled CTCs seeded primary tumors in both models. Seeded primary tumors groups grew faster than control groups (P < 0.05), which was partially attributed to the CTCs having a higher proliferation rate and higher vascular endothelial growth factor expression after self-seeding. Conditioned media of primary osteosarcoma cells attracted CTCs, through an IL-6-dependent mechanism.

CONCLUSIONS

CTC tumor self-seeding occurs in osteosarcoma and promotes the growth of primary osteosarcoma. CTCs appear to be recruited by cytokines secreted by primary osteosarcoma cells, particularly IL-6.

A study comparing three different laser-assisted hatching techniques

PURPOSE OF INVESTIGATION

Laser-assisted hatching (LAH) is recognized as a useful technology to improve clinical pregnancy rates and implantation rates. This study reports the differences between a new LAH method and two conventional LAH techniques.

MATERIALS AND METHODS

The authors studied 151 patients with repeated implantation failure, who were divided into three groups.

RESULTS

In group 1, the zona pellucida (ZP) was opened using LAH (n = 52). In group 2, laser-assisted thinning was performed to dissolve the outer layer of the ZP (n = 49). In group 3, laser-assisted thinning was performed to dissolve the inner layer of the ZP (n = 50). The clinical pregnancy rates and implantation rates among the groups were compared. The results demonstrate that there are significant differences in the clinical pregnancy rates and implantation rates between group 3 and the other two groups.

CONCLUSION

Performing laser-assisted thinning to dissolve the inner layer of the ZP markedly increases the pregnancy rates and implantation rates of patients with repeated implantation failure.

Open reduction and internal fixation versus external fixation for unstable distal radial fractures: a meta-analysis

PURPOSE

To compare the clinical outcomes of open reduction and internal fixation (ORIF) versus the ones of closed reduction and external fixation (EF) in the treatment of distal radial fractures.

METHODS

We performed a meta-analysis of randomized controlled trials that compared the clinical results of ORIF to EF in the treatment of distal radial fractures. A systemic retrieve from PubMed, EMBASE, OVID and Cochrane Collaboration CENTRAL database resulted in 11 studies with 824 patients. We thus performed data synthesis using RevMan (version 5.1).

RESULTS

Superior statistical differences were observed for DASH scores (at 3, 6 and 12 months follow-up) grip strength (at 3 months follow-up), volar tilt (at 12 months follow-up), flexion and supination (at 3 months follow-up), and extension (at 3 and 6 months follow-up) in ORIF patients group, compared with those in EF group. We also found a significantly higher risk of infection associated with EF. There was no significant difference in the incidence of malunion and median nerve dysfunction.

CONCLUSION

Regarding surgical fixation of unstable distal radius fractures, ORIF yields significantly better subjective outcome (DASH scores) the first year after operation, restoration of anatomic volar tilt, and forearm flexion and extension at the end of the follow-up period. However, EF results in higher incidence of infection compared to ORIF. ORIF is equal to EF for either grip strength, or range of motion of the injured wrist, or incidence of malunion or median nerve dysfunction at the end of the follow-up period.

LEVEL OF EVIDENCE

Level II. Therapeutic study.

Inhibition of activin receptor-like kinase 5 induces matrix metallopeptidase 9 expression and aggravates lipopolysaccharide-induced pulmonary injury in mice

BACKGROUND

TGF-β (Transforming Growth Factor-β) mediates its biological effects through members of activin receptor-like kinase (ALK) family and TGF-β/Smad3 signaling link inflammation to pulmonary fibrosis.

AIM

The aim of this study was to evaluate the role of SB431542 as a specific inhibitor of Activin receptor-Like Kinase 5 (ALK5) in pneumonic injury.

MATERIALS AND METHODS

Anesthetized and endo-tracheally intubated C57BL/6 mice were randomized to three groups: the control group with intra-tracheal instillation of 1.5 mg/kg normal saline (NS); LPS stimulation group with intra-tracheal instillation of 3 mg/kg LPS (lipopolysaccharide); and LPS+SB431542 group with intra-peritoneal (i.p.) injection of 4.2 mg/kg SB431542 1 h before intra-tracheal instillation of 3 mg/kg LPS. The lung tissue was obtained 6 h after injury, and the degree of pulmonary injury was evaluated by pathologic scoring. The lung wet/dry weight ratio was measured. TNF-α, IL-1β, and MMP-9 (matrix metallopeptidase-9) mRNA expression levels were assayed by real time PCR (polymerase chain reaction). The content of MMP-9 total protein was measured by Western blotting. The content of active MMP-9 was detected by gelatin zymography. Location of MMP-9 in mouse lung tissue was monitored by immunohistochemistry.

RESULTS

The results showed that (1) pathologic changes including interstitial pulmonary edema, neutrophil infiltration, alveolar edema and hemorrhage were observed 6 h after LPS instillation. The lung wet/dry weight rate and pathologic scores confirmed that SB431542 administration aggravated LPS injury to the mouse lung; (2) the amount of TNF-α and IL-1β mRNA expression in LPS groups was significantly higher than that in the control group, and the highest in LPS+SB431542 group; (3) the amount of MMP-9 mRNA and MMP-9 protein expression and active MMP-9 in the lung tissue of LPS groups was significantly higher than that in the control group 6 h after injury, and the highest in LPS+SB431542 group; and (4) MMP-9 expression was mainly observed in the airway epithelial cells, vascular smooth muscle cells and cytoplasm of inflammatory cells as shown by immunohistochemistry, and brownish yellow uniformed stained areas were also seen in the exudate from part of the alveoli.

CONCLUSIONS

These results indicate that blocking the activity of TGF-β/Smad pathway by specific inhibitor SB431542 of ALK5 promoted the releaser of large amounts of TNF-α, IL-1β and other pro-inflammatory cytokines from the lung tissue of mice sustaining acute lung injury (ALI). At the same time, the amount and activity of MMP-9 expression in the lung were increased, and MMP-9 expression was mainly located in the airway epithelial cells, vascular smooth muscle cells and inflammatory cells, causing increased permeability of the pulmonary blood vessels, degradation of the extracellular matrix and destruction of the normal lung tissue structures, which directly or indirectly promotes the progression of pulmonary inflammatory responses and aggravates ALI.

Gene expression profiling of dedifferentiated human articular chondrocytes in monolayer culture

OBJECTIVE

When primary chondrocytes are cultured in monolayer, they undergo dedifferentiation during which they lose their phenotype and their capacity to form cartilage. Dedifferentiation is an obstacle for cell therapy for cartilage degeneration. In this study, we aimed to systemically evaluate the changes in gene expression during dedifferentiation of human articular chondrocytes to identify underlying mechanisms.

METHODS

RNA was isolated from monolayer-cultured primary human articular chondrocytes at serial passages. Gene expression was analyzed by microarray. Based on the microarray analysis, relevant genes and pathways were identified. Their functions in chondrocyte dedifferentiation were further investigated.

RESULTS

In vitro expanded human chondrocytes showed progressive changes in gene expression. Strikingly, an overall decrease in total gene expression was detected, which was both gradual and cumulative. DNA methylation was in part responsible for the expression downregulation of a number of genes. Genes involved in many pathways such as the extracellular-signal-regulated kinase (ERK) and Bone morphogenetic protein (BMP) pathways exhibited significant changes in expression. Inhibition of ERK pathway did not show dramatic effects in counteracting dedifferentiation process. BMP-2 was able to decelerate the dedifferentiation and reinforce the maintenance of chondrocyte phenotype in monolayer culture.

CONCLUSION

Our study not only improves our knowledge of the intricate signaling network regulating maintenance of chondrocyte phenotype, but also contributes to improved chondrocyte expansion and chondrogenic performance for cell therapy.

Effect of clopidogrel with or without omeprazole in patients with carotid artery stenting

BACKGROUND

Recent concerns have been raised about the potential for proton pump inhibitors (PPIs) to blunt the efficacy of clopidogrel. We observed the effect of clopidogrel plus aspirin with or without omeprazole in patients with carotid stenoses after they received placement of carotid stents.

METHODS

Sixty-four consecutive patients treated with percutaneous carotid artery stenting (CAS) comprised the sample. All enrolled patients underwent the C13 urea breath test (C13 UBT) before CAS. Patients with Helicobacter pylori infection and a history of peptic ulcer were assigned dual antiplatelet combination with omeprazole. Others received dual antiplatelet without omeprazole. Transcranial Doppler and ultrasonography were performed to assess the middle cerebral artery and carotid artery in follow-up at three months and six months.

RESULTS

Eight patients had gastrointestinal bleeding; the event rate was 22.6% without omeprazole and 3.8% with omeprazole. The rate of gastrointestinal bleeding was reduced with omeprazole as compared without omeprazole (p = 0.026, p < 0.05). The two groups did not differ significantly in the rate of in-stent restenosis and thrombus through transcranial Doppler and ultrasonography.

CONCLUSION

Among patients receiving dual antiplatelet therapy, prophylactic use of omeprazole reduced the rate of upper gastrointestinal bleeding. There was no apparent interaction between clopidogrel and omeprazole in patients with carotid artery stenting.

MicroRNA-221 induces cell survival and cisplatin resistance through PI3K/Akt pathway in human osteosarcoma

Background

MicroRNAs are short regulatory RNAs that negatively modulate protein expression at a post-transcriptional and/or translational level and are deeply involved in the pathogenesis of several types of cancers. Specifically, microRNA-221 (miR-221) is overexpressed in many human cancers, wherein accumulating evidence indicates that it functions as an oncogene. However, the function of miR-221 in human osteosarcoma has not been totally elucidated. In the present study, the effects of miR-221 on osteosarcoma and the possible mechanism by which miR-221 affected the survival, apoptosis, and cisplatin resistance of osteosarcoma were investigated.

Methodology/Principal Findings

Real-time quantitative PCR analysis revealed miR-221 was significantly upregulated in osteosarcoma cell lines than in osteoblasts. Both human osteosarcoma cell lines SOSP-9607 and MG63 were transfected with miR-221 mimic or inhibitor to regulate miR-221 expression. The effects of miR-221 were then assessed by cell viability, cell cycle analysis, apoptosis assay, and cisplatin resistance assay. In both cells, upregulation of miR-221 induced cell survival and cisplatin resistance and reduced cell apoptosis. In addition, knockdown of miR-221 inhibited cell growth and cisplatin resistance and induced cell apoptosis. Potential target genes of miR-221 were predicted using bioinformatics. Moreover, luciferase reporter assay and western blot confirmed that PTEN was a direct target of miR-221. Furthermore, introduction of PTEN cDNA lacking 3′-UTR or PI3K inhibitor LY294002 abrogated miR-221-induced cisplatin resistance. Finally, both miR-221 and PTEN expression levels in osteosarcoma samples were examined by using real-time quantitative PCR and immunohistochemistry. High miR-221 expression level and inverse correlation between miR-221 and PTEN levels were revealed in osteosarcoma tissues.

Conclusions/Significance

These results for the first time demonstrate that upregulation of miR-221 induces the malignant phenotype of human osteosarcoma whereas knockdown of miR-221 reverses this phenotype, suggesting that miR-221 could be a potential target for osteosarcoma treatment.

miR-34a inhibits the metastasis of osteosarcoma cells by repressing the expression of CD44

Osteosarcoma is the most common type of malignant bone tumor in children and adolescents and approximately 30% of patients develop lung metastasis, which is the leading cause of mortality. In this study, we investigated the role of miR-34a in the invasion and metastasis of osteosarcoma cells by examining its expression level and functional pattern in these cells. miR-34a mimics were transfected into the highly metastatic subline, F5M2, and into the F4 subline with low metastatic potential of the paired human osteosarcoma cell line, SOSP‑9607. Cell viability patterns, cell migration and alterations in gene expression levels were assessed by real-time PCR, and changes in protein levels were assessed by immunocytochemistry and western blot analysis. The ectopic overexpression of miR-34a significantly inhibited the migration and invasive ability of osteosarcoma cells by repressing the expression of CD44. These data suggest that miR-34a plays a tumor suppressor role in the metastasis of osteosarcoma cells by repressing the expression of CD44. Of note, studies have also suggested that the CD44 protein correlates with the metastatic potential of several malignant tumors. Therefore, it can be concluded that through the inhibition of CD44 expression levels, miR-34a plays a significant role in the migration and invasion of osteosarcoma cells.

Immunologic response to tumor ablation with irreversible electroporation

Background

Irreversible electroporation (IRE) is a promising technique for the focal treatment of pathologic tissues, which involves placing minimally invasive electrodes within the targeted region. However, the knowledge about the therapeutic efficacy and immune reactions in response to IRE remains in its infancy.

Methods

In this work, to detect whether tumor ablation with IRE could trigger the immunologic response, we developed an osteosarcoma rat model and applied IRE directly to ablate the tumor. In the experiment, 118 SD rats were randomized into 4 groups: the control, sham operation, surgical resection, and IRE groups. Another 28 rats without tumor cell implantation served as the normal non-tumor-bearing group. We analyzed the changes in T lymphocyte subsets, sIL-2R and IL-10 levels in the peripheral blood one day before operation, as well as at 1, 3, 7,14 and 21 days after the operation. Moreover, splenocytes were assayed for IFN-γ and IL-4 production using intracellular cytokine staining one day before the operation, as well as at 7 and 21 days after operation.

Results

We found that direct IRE completely ablated the tumor cells. A significant increase in peripheral lymphocytes, especially CD3⁺ and CD4⁺ cells, as well as an increased ratio of CD4⁺/CD8⁺ were detectable 7 days after operation in both the IRE and surgical resection groups. Compared with the surgical resection group, the IRE group exhibited a stronger cellular immune response. The sIL-2R level of the peripheral blood in the IRE group decreased with time and was significantly different from that in the surgical resection group. Moreover, ablation with IRE significantly increased the percentage of IFN-γ-positive splenocytes.

Conclusion

These findings indicated that IRE could not only locally destroy the tumor but also change the status of cellular immunity in osteosarcoma-bearing rats. This provides experimental evidence for the clinical application of IRE in osteosarcoma treatment.

miR-183 inhibits the metastasis of osteosarcoma via downregulation of the expression of Ezrin in F5M2 cells

Osteosarcoma is the most common primary malignancy of bone in teenagers and approximately 30% of patients develop lung metastasis, which is the leading cause of mortality. Recent studies suggest that the Ezrin protein is correlated with the metastatic potential of several malignant tumors. In our study, ectopic overexpression of miR-183 repressed the expression levels of Ezrin and significantly inhibited the motility and invasion of osteosarcoma cells. This suggests that miR-183 may possibly play a tumor suppressor role in the metastasis of osteosarcoma by downregulating Ezrin expression levels. These findings show that through inhibition of Ezrin expression levels, miR-183 is significantly involved in cell migration and invasion of osteosarcoma.

[Effect of silencing p53 and p21 on delaying senescence of nucleus pulposus cells]

OBJECTIVE The senescence and death of nucleus pulposus (NP) cells are the pathologic basis of intervertebral disc degeneration (IVD). To investigate the molecular phenotypes and senescent mechanism of NP cells, and to identify the method of alleviating senescence of NP cells.

METHODS

The primary NP cells were harvested from male Sprague Dawley rats (8-10 weeks old); the hypoxia inducible factor 1alpha(HIF-1alpha, HIF-1beta matrix metalloproteinase 2 (MMP-2), and collagen type II as phenotypic markers were identified through immunocytochemical staining. RT-PCR and Western blot were used to test the silencing effect of NP cells after the NP cells were transfected with p53 and p21 small interference RNA (siRNA). Senescence associated-beta-galactosidase (SA-beta-gal) staining was used to test the senescence of NP cells, flow cytometry to test the change of cell cycle, the growth curve analysis to test the NP cells proliferation.

RESULTS

Immunocytochemical staining showed that NP cells expressed HIF-1alpha HIF-1beta, MMP-2, and collagen type II. RT-PCR and Western blot showed that the relative expressions of mRNA and protein of p53 and p21 were significantly inhibited in NP cells at passage 35 after transfected with p53 and p21 siRNA. The percentage of SA-Pbetagal-positive NP cells at passage 35 was significantly higher than that at passage 1 (P < 0.001). And the percentage of SA-Pbetagal-positive NP cells in the p53 siRNA transfection group and p21 siRNA transfection group were significantly lower than that in control group (P < 0.001). The flow cytometry showed that the GC1phase of NP cells in p53 siRNA transfection group and p21 siRNA transfection group was significantly shorter than that in control group (P < 0.05), but the S phase of NP cells in p53 siRNA transfection group and p21 siRNA transfection group were significantly longer than that in control group (P < 0.05). In addition, the growth curve showed that the growth rate of NP cells could be promoted after transfection of p53 and p21 siRNA.

CONCLUSION

he senescence of NP cells can be alleviated by silencing of p53 and p21. The effect of alleviating senescence can even ameliorate the progress of IVD and may be a useful and potential therapy for IVD.

Expression of hypoxia-inducible factor-1α, vascular endothelial growth factor and matrix metalloproteinase-2 in sacral chordomas

Hypoxia-inducible factor-1α (HIF-1α) has been reported to transactivate the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP-2), which are frequently overexpressed in numerous types of cancer and are known to be significant regulators of angiogenesis. Few studies have investigated the role of these factors in solid tumors, particularly chordomas, which are rare tumors that are thought to originate from notochordal remnants. To clarify whether HIF-1α is involved in angiogenesis in chordoma tissues, we examined the expression of HIF-1α, VEGF and MMP-2 with immunohistochemistry using a tissue microarray containing 35 chordoma samples. The results indicated that HIF-1α, VEGF and MMP-2 are expressed in the majority of chordoma samples. VEGF expression was significantly correlated with HIF-1α and MMP-2 expression, as well as with microvessel density (MVD). However, the prognosis of the chordoma patients was not significantly associated with the expression of these factors, but was associated with MVD. The results therefore showed that there is a correlation between the expression of HIF-1α, VEGF and MMP-2 in chordomas and that the angiogenic process is a potential therapeutic target for chordomas.

The clinical value of CXCR4, HER2 and CD44 in human osteosarcoma: A pilot study

The biological markers CXCR4, HER2 and CD44 are involved in tumor growth and the homing of cancer cells to distant sites. The aim of this retrospective, case-control study was to evaluate whether the expression of CXCR4, HER2 and CD44 correlated with poor prognosis. Expression levels of CXCR4, HER2 and CD44 were evaluated by immunohistochemical staining in paraffin-embedded tissue sections of malignant primary osteosarcoma and related metastatic carcinoma from 63 patients, at a median follow-up of 5.5 years (range 1-10 years). Associations between these parameters and clinical features were examined. Of the 63 specimens, there were 38 HER2-positive, 57 CXCR4-positive and 62 CD44-positive cases. There were 36 cases of HER2 and CXCR4 co-expression, 38 cases of HER2 and CD44 co-expression and 56 cases of CXCR4 and CD44 co-expression. A total of 33 cases were CXCR4, HER2 and CD44 co-positive. Surface expression of CXCR4, HER2 and CD44 was high in the selected tissue samples, and CD44 was the most highly expressed. We observed a significant trend for a higher frequency of the expression of the three biomarkers in high-grade compared to low-grade osteosarcoma. Our results suggest a pivotal role of CXCR4, HER2 and CD44 expression as a prognostic factor of malignant human osteosarcoma. A larger study is ongoing to confirm these results.

βA3/A1-Crystallin controls anoikis-mediated cell death in astrocytes by modulating PI3K/AKT/mTOR and ERK survival pathways through the PKD/Bit1-signaling axis

During eye development, apoptosis is vital to the maturation of highly specialized structures such as the lens and retina. Several forms of apoptosis have been described, including anoikis, a form of apoptosis triggered by inadequate or inappropriate cell–matrix contacts. The anoikis regulators, Bit1 (Bcl-2 inhibitor of transcription-1) and protein kinase-D (PKD), are expressed in developing lens when the organelles are present in lens fibers, but are downregulated as active denucleation is initiated. We have previously shown that in rats with a spontaneous mutation in the Cryba1 gene, coding for βA3/A1-crystallin, normal denucleation of lens fibers is inhibited. In rats with this mutation (Nuc1), both Bit1 and PKD remain abnormally high in lens fiber cells. To determine whether βA3/A1-crystallin has a role in anoikis, we induced anoikis in vitro and conducted mechanistic studies on astrocytes, cells known to express βA3/A1-crystallin. The expression pattern of Bit1 in retina correlates temporally with the development of astrocytes. Our data also indicate that loss of βA3/A1-crystallin in astrocytes results in a failure of Bit1 to be trafficked to the Golgi, thereby suppressing anoikis. This loss of βA3/A1-crystallin also induces insulin-like growth factor-II, which increases cell survival and growth by modulating the phosphatidylinositol-3-kinase (PI3K)/AKT/mTOR and extracellular signal-regulated kinase pathways. We propose that βA3/A1-crystallin is a novel regulator of both life and death decisions in ocular astrocytes.

MicroRNA expression during osteogenic differentiation of human multipotent mesenchymal stromal cells from bone marrow

MicroRNAs comprise a group of non-coding small RNAs (17-25 nt) involved in post-transcriptional regulation that have been identified in various plants and animals. Studies have demonstrated that miRNAs are associated with stem cell self-renewal and differentiation and play a key role in controlling stem cell activities. However, the identification of specific miRNAs and their regulatory roles in the differentiation of multipotent mesenchymal stromal cells (MSCs) have so far been poorly defined. We isolated and cultured human MSCs and osteo-differentiated MSCs from four individual donors. miRNA expression in MSCs and osteo-differentiated MSCs was investigated using miRNA microarrays. miRNAs that were commonly expressed in all three MSC preparations and miRNAs that were differentially expressed between MSCs and osteo-differentiated MSCs were identified. Four underexpressed (hsa-miR-31, hsa-miR-106a, hsa-miR-148a, and hsa-miR-424) and three novel overexpressed miRNAs (hsa-miR-30c, hsa-miR-15b, and hsa-miR-130b) in osteo-differentiated MSCs were selected and their expression were verified in samples from the fourth individual donors. The putative targets of the miRNAs were predicted using bioinformatic analysis. The four miRNAs that were underexpressed in osteo-differentiated MSCs were predicted to target RUNX2, CBFB, and BMPs, which are involved in bone formation; while putative targets for miRNAs overexpressed in osteo-differentiated MSCs were MSC maker (e.g., CD44, ITGB1, and FLT1), stemness-maintaining factor (e.g., FGF2 and CXCL12), and genes related to cell differentiation (e.g., BMPER, CAMTA1, and GDF6). Finally, hsa-miR-31 was selected for target verification and function analysis. The results of this study provide an experimental basis for further research on miRNA functions during osteogenic differentiation of human MSCs.

Antitumor effect of sFlt-1 gene therapy system mediated by Bifidobacterium Infantis on Lewis lung cancer in mice

Soluble fms-like tyrosine kinase receptor (sFlt-1) is a soluble form of extramembrane part of vascular endothelial growth factor receptor-1 (VEGFR-1) that has antitumor effects. Bifidobacterium Infantis is a kind of non-pathogenic and anaerobic bacteria that may have specific targeting property of hypoxic environment inside of solid tumors. The aim of this study was to construct Bifidobacterium Infantis-mediated sFlt-1 gene transferring system and investigate its antitumor effect on Lewis lung cancer (LLC) in mice. Our results demonstrated that the Bifidobacterium Infantis-mediated sFlt-1 gene transferring system was constructed successfully and the system could express sFlt-1 at the levels of gene and protein. This system could not only significantly inhibit growth of human umbilical vein endothelial cells induced by VEGF in vitro, but also inhibit the tumor growth and prolong survival time of LLC C57BL/6 mice safely. These data suggest that Bifidobacterium Infantis-mediated sFlt-1 gene transferring system presents a promising therapeutic approach for the treatment of cancer.

Skewing the Balance of Regulatory T-Cells and T-Helper 17 Cells in Breast Cancer Patients

This study investigated the distribution of interleukin (IL)-17-producing CD4+ T-cells (T-helper [Th17] cells) in relation to CD4+CD25+CD127− cells (regulatory T-cells [Treg]) in tumour-infiltrating lymphocytes (TILs) and peripheral blood mononuclear cells (PBMCs) from breast cancer patients. The Th17 and Treg cells were evaluated by flow cytometry and reported as a percentage of total CD4+ cells. In TILs from early breast cancer patients ( n = 12), the frequency of Th17 cells was significantly higher than in PBMCs (14.5 ± 7.2% versus 6.9 ± 2.1%). In TILs from patients with advanced breast cancer ( n = 15), the frequency of Th17 cells was also significantly higher than that in PBMCs (9.1 ± 5.7% versus 3.2 ± 2.3%) but lower compared with early disease. The Th17/Treg ratio in TILs was markedly increased in early versus advanced disease. In conclusion, Th17 and Treg cell accumulation in the tumour microenvironment of breast cancer occurred in early disease; Th17 cell infiltration gradually decreased and Treg cells accumulated with disease progression.