Abstract P2-14-07: A systematic review of the clinical evidence regarding PIP breast implants

Background: Mammary implants marketed by Poly Implant Prothèse (PIP) were found to contain industrial grade silicone and this caused heightened anxiety and extensive publicity regarding their safety in humans. These implants were used in a large number of patients worldwide for augmentation or breast reconstruction.

Methods: Articles were identified by searches of Medline, PubMed, Embase and Google Scholar databases up to March 2014 using the terms: "PIP", "Poly Implant Prothèse","breast implants" and "augmentation mammoplasty" or "silicone" In addition the websites of regulating bodies in Europe, USA and Australia were searched for reports related to PIP mammary implants.

Results: PIP mammary implants are more likely to rupture than other implants and can cause adverse effects in the short to the medium term related to the symptoms of rupture such as pain, lumps in the breast and axilla and anxiety. Based on peer-reviewed published studies we have calculated an overall rupture rate of 14.5% (383/2635) for PIP implants.

Conclusions: There is no evidence that PIP implant rupture causes long-term adverse health effects in humans so far. The long-term adverse effects usually arise from inappropriate extensive surgery, such as axillary lymph node dissection or extensive resection of breast tissue due to silicone leakage.

Citation Format: Umar Wazir, Abdul Kasem, Kefah Mokbel. A systematic review of the clinical evidence regarding PIP breast implants [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-14-07.

The role of death-associated protein 3 in apoptosis, anoikis and human cancer

Death-associated protein 3 (DAP3) is a molecule with a significant role in the control of both apoptosis and anoikis. Apoptosis is the predominant type of programmed cell death (PCD) which may occur in response to irreparable damage to DNA, or in response to induction by inflammatory cells. Anoikis is subset of apoptosis which occurs in epithelial cells in response to detachment from the surrounding matrix. Both apoptosis and anoikis are of interest in the context of carcinogenesis. In this review, we shall discuss apoptosis and anoikis, and the recent literature regarding the role of DAP3 in both these pathways.

Effects of the knockdown of death-associated protein 3 expression on cell adhesion, growth and migration in breast cancer cells

The death-associated protein 3 (DAP3) is a highly conserved phosphoprotein involved in the regulation of autophagy. A previous clinical study by our group suggested an association between low DAP3 expression and clinicopathological parameters of human breast cancer. In the present study, we intended to determine the role of DAP3 in cancer cell behaviour in the context of human breast cancer. We developed knockdown sub-lines of MCF7 and MDA-MB-231, and performed growth, adhesion, invasion assays and electric cell-substrate impedance sensing (ECIS) studies of post-wound migration of the cells. In addition, we studied the mRNA expression of caspase 8 and 9, death ligand signal enhancer (DELE), IFN-β promoter stimulator 1 (IPS1), cyclin D1 and p21 in the control and knockdown sub-lines. The knockdown sub-lines of MCF7 and MDA-MB-231 had significantly increased adhesion and decreased growth when compared to the controls. Furthermore, invasion and migration were significantly increased in the MDA-MB-231DAP3kd cells vs. the controls. The expression of caspase 9 and IPS1, known components of the apoptosis pathway, were significantly reduced in the MCF7DAP3kd cells (p=0.05 and p=0.003, respectively). We conclude that DAP3 silencing contributes to breast carcinogenesis by increasing cell adhesion, migration and invasion. It is possible that this may be due to the activity of focal adhesion kinase further downstream of the anoikis pathway. Further research in this direction would be beneficial in increasing our understanding of the mechanisms underlying human breast cancer.

Emerging gene-based prognostic tools in early breast cancer: First steps to personalised medicine

Breast cancer remains a major cause of neoplastic disease in much of the developed world. The majority of cases are diagnosed with oestrogen receptor (ER)-positive and human epidermal growth factor receptor-2 negative invasive ductal carcinoma and are treated predominantly by surgery which includes sentinel node biopsy and adjuvant endocrine therapy ± adjuvant radiotherapy. It is believed that an indeterminate subset of the patient population is needlessly incurring chemotherapy related morbidity without attaining any increase in survival due to therapy. Furthermore in the era of extended adjuvant endocrine therapy it is important to identify those patients who can be safely treated with 5 years rather than 10 years of endocrine therapy thus optimising the benefit-risk balance. This perception has propelled the development of more personalised prognostic tools for newly diagnosed cases of ER-positive breast cancer. In this article, we shall review the evidence regarding the currently available gene assays for human breast cancer.

Towards optimal management of the axilla in the context of a positive sentinel node biopsy in early breast cancer

The sentinel lymph node biopsy (SLNB) was initially pioneered for staging melanoma in 1994 and it has been subsequently validated by several trials, and has become the new standard of care for patients with clinically node negative invasive breast cancer. The focussed examination of fewer lymph nodes in addition to improvements in histopathological and molecular analysis has increased the rate at which micrometastases and isolated tumour cells are identified. In this article we review the literature regarding the optimal management of the axilla when the SLNB is positive for metastatic disease based on level 1 evidence derived from randomised clinical trials.

Towards optimal treatment of ductal carcinoma in situ

Ductal carcinoma in situ (DCIS) is a non-obligate precursor of invasive breast cancer with a variable biological behavior which is difficult to accurately predict using the current clinico-pathological parameters. Randomized controlled trials have demonstrated that adjuvant radiotherapy (RT) reduces the risk of local recurrence after adequate local excision of DCIS. Tamoxifen may be considered as an adjuvant endocrine treatment in patients with high risk estrogen receptor positive disease. There is however a growing consensus that RT can be safely omitted in a subgroup of patients with favorable biological features in order to avoid overtreatment. The sentinel node biopsy is not routinely indicated but should be considered in women undergoing mastectomy for DCIS. The discovery of molecular signatures that accurately predict the biological behavior of this common malignancy will facilitate a personalized treatment approach in the future.

Current state of mTOR targeting in human breast cancer

BACKGROUND/AIM

The mammalian, or mechanistic, target of rapamycin (mTOR) pathway has been implicated in several models of human oncogenesis. Research in the role of mTOR in human oncogenesis remains a field of intense activity. In this mini-review, we intend to recount our current understanding of the mTOR pathway, its interactions, and its role in human carcinogenesis in general, and breast cancer in particular.

MATERIALS AND METHODS

We herein outline the discrete components of the two complexes of mTOR, and attempt to define their distinct roles and interactions. Furthermore, we review current developments in the therapeutic targeting of mTOR in human breast cancer.

RESULTS

Our understanding of the organisation and interactions of the mTOR pathway continues to evolve. There has been significant incremental, albeit slow, progress in the therapeutic targeting of the mTOR pathway in human breast cancer.

CONCLUSION

Continued progress in the field would require a better understanding of the role of the mTOR pathway in human breast cancer. By summarizing the current literature, this review will provide useful information on the topic.

Evolving role of skin sparing mastectomy

Skin sparing mastectomy (SSM) can facilitate immediate breast reconstruction and is associated with an excellent aesthetic result. The procedure is safe in selected cases; including invasive tumours < 5 cm, multi-centric tumours, ductal carcinoma in situ and for risk-reduction surgery. Inflammatory breast cancers and tumours with extensive involvement of the skin represent contra-indications to SSM due to an unacceptable risk of local recurrence. Prior breast irradiation or the need for post-mastectomy radiotherapy do not preclude SSM, however the aesthetic outcome may be compromised. Preservation of the nipple areola complex is safe for peripherally located node negative tumours. An intraoperative frozen section protocol for the retro-areolar tissue should be considered in these cases. The advent of acellular tissue matrix systems has enhanced the scope of implant-based immediate reconstruction following SSM. Cell-assisted fat transfer is emerging as a promising technique to optimise the aesthetic outcome.

mRNA expression of DOK1-6 in human breast cancer

AIM: To examine the expression of downstream of tyrosine kinase (DOK)1-6 genes in normal and breast cancer tissue and correlated this with several clinico-pathological and prognostic factors.

METHODS: DOK1-6 mRNA extraction and reverse transcription were performed on fresh frozen breast cancer tissue samples (n = 112) and normal background breast tissue (n = 31). Tissues were collected between 1991 and 1996 at two centres and all patients underwent mastectomy and ipsilateral axillary node dissection. All tissues were randomly numbered and the details were only made known after all analyses were completed. Transcript levels of expression were determined using real-time polymerase chain reaction and analyzed against TNM stage, tumour grade and clinical outcome over a 10-year follow-up period.

RESULTS: DOK-2 and DOK-6 expression decreased with increasing TNM stage. DOK-6 expression decreased with increasing Nottingham Prognostic Index (NPI) [NPI-1 vs NPI-3 (mean copy number 15.4 vs 0.22, 95%CI: 2.7-27.6, P = 0.018) and NPI-2 vs NPI-3 (mean copy number 7.6 vs 0.22, 95%CI: 0.1-14.6, P = 0.048)]. After a median follow up period of 10 years, higher levels of DOK-2 expression were found among patients who remained disease-free compared to those who developed local or distant recurrence (mean copy number 3.94 vs 0.0000096, 95%CI: 1.0-6.85, P = 0.0091), and distant recurrence (mean copy number 3.94 vs 0.0025, 95%CI: 1.0-6.84, P = 0.0092). Patients who remained disease-free had higher levels of DOK-6 expression compared to those who died from breast cancer.

CONCLUSION: Decreasing expression levels of DOK-2 and DOK-6 with increased breast tumour progression supports the notion that DOK-2 and DOK-6 behave as tumour suppressors in human breast cancer.

The interaction between DAP1 and autophagy in the context of human carcinogenesis

Autophagy is an evolutionarily-conserved catabolic process which furthers cell survival, especially in times of nutritional stress. Whilst being by itself a pro-survival mechanism, it has many areas of overlap with apoptosis. Autophagic cell death is recognised as a subset of programmed cell death, with features more typical of autophagy rather than classical apoptosis. The mechanisms preventing autophagy from unravelling into autophagic cell death are still the subject of much controversy. We discuss the current understanding of these mechanisms, including recent research regarding the role of death-associated protein-1 in autophagy and apoptosis.

Abstract P6-02-02: mRNA expression of death associated protein 3 (DAP3) and human breast cancer: Clinical correlations and in vitro evidence

BACKGROUND: To our knowledge, this study is the first to focus on the potential role for death-associated protein 3 (DAP3) in human breast cancer.

MATERIAL AND METHODS: mRNA expression of DAP3 in breast cancer tissues (n = 127) and normal background tissues (n = 33) were determined using quantitative polymerase chain reaction (qPCR) and were correlated with clinico-pathological data accumulated over a 10-year follow-up period.

Furthermore the effects of DAP3 knock down in breast cancer cell lines (MCF-7 and MDA-MB-231) were investigated. The cells were subjected to conventional growth, adhesion and invasion assays.

In addition to the above, electric cell-substrate impedance sensing (ECIS) assay and annexin V/propidium iodide binding apoptosis assay were performed. For the apoptosis assay, the cells were subjected to 48 to 72 hours of serum hunger (depending on cell line) before being analyzed using a flow cytometer.

RESULTS: The expression of DAP3 mRNA was demonstrated to decrease with increasing Nottingham Prognostic Index (NPI2 vs. NPI3, p = 0.036), TNM stage (TNM1 vs. 3, p = 0.07), and tumour grade (grade 1 vs. 3, p = 0.08). Lower DAP3 expression levels were significantly associated with local recurrence (p = 0.013), distant metastasis (p = 0.0057) and mortality (p = 0.019).

Kaplan-Meier plot analysis suggests that patient with higher levels of DAP3 expression had better overall survival compared to patients with lower levels of DAP3 expression (p = 0.075).

DAP3 knock down strains in both cell lines demonstrated increased growth and migration compared to controls during ECIS.

In addition, DAP3 knock down strains of MCF-7 appeared more resistant to serum hunger when compared to controls during the apoptosis assay.

CONCLUSIONS: This study demonstrates an inverse association between DAP3 mRNA levels and tumour stage and clinical stage in breast cancer. This is in keeping with the role of DAP3 as a pro-apoptotic protein. The in vitro evidence lends further credence to this hypothesis. The role of DAP3 may require further investigation to better understand the role of apoptosis in breast carcinogenesis, and may potentially serve as a prognostic marker for human breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-02-02.

Abstract P6-04-14: mRNA expressions of lamin B1 and lamin B receptor: Clinical correlations with human breast cancer

BACKGROUND: Lamin B (LMNB) and lamin B receptor (LBR) are key components of the nuclear envelope, with roles in chromosomal stability, DNA repair, and cell differentiation. Lamins provide structural support to the nuclear envelope, while LBR is believed to anchor lamin B to the envelope. In addition, LBR also has a number of downstream mediators which affect cell cycle and cell differentiation.

Classically, they have been implicated in a spectrum of largely congenital ailments including certain forms of muscle dystrophy and progeria. These conditions are collectively referred to as “laminopathies”.

More recently, defects in the expression of lamins have been implicated in neoplasias of the colon, prostate, liver and ovaries.

In this study, we have endeavoured to elucidate the relationships between the mRNA expressions of LMNB1 and LBR and the clinicopathological parameters of human breast cancer.

METHODS: Breast cancer tissues (n = 115) and associated non-cancerous tissue (ANCT) (n = 30) underwent reverse transcription and quantitative PCR. Transcript levels were correlated with clinicopathological data.

RESULTS: LMNB1 mRNA expression was higher in ANCT as compared to cancerous tissue (ANCT vs. cancerous tissue: 0.12 vs. 0.00; p = &lt;0.0001). This difference remained highly significant in all patient categories by tumour grade and clinical stage.

In addition, the expression of LMNB1 declined with worsening clinical outcome. This association was statistically significant when comparing patient with disease-free survival with disease related mortalities (Disease-free vs. mortalities: 0.0011 vs. 0.000; p = 0.0177).

LBR mRNA expression was found to be directly associated with tumour grade (grade 1 vs.3: 0.00 vs. 0.00; p = 0.0479) and the Nottingham Prognostic Index (NPI1 vs. 3: 0.00 vs. 0.00; p = 0.0551).

CONCLUSIONS: To our knowledge, this is the first study to suggest such a role for LMNB1 and LBR in human breast cancer.

The contrasting relationships of LMNB1 and LBR expressions with the clinicopathological parameters of human breast cancer may suggest that disruptions in the physiologically normal interactions between these molecules in the nuclear envelope may serve as pathway leading towards the pathogenesis of human breast cancer. Potentially this may be a significant pathway requiring further investigation to be better understood, in order to identify further potential areas for therapeutic intervention.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-04-14.

The clinicopathological significance of lamin A/C, lamin B1 and lamin B receptor mRNA expression in human breast cancer

Lamin A/C (LMNA), lamin B1 (LMNB1) and lamin B receptor (LBR) have key roles in nuclear structural integrity and chromosomal stability. In this study, we have studied the relationships between the mRNA expressions of A-type lamins, LMNB1 and LBR and the clinicopathological parameters in human breast cancer. Samples of breast cancer tissues (n = 115) and associated non-cancerous tissue (ANCT; n = 30) were assessed using reverse transcription and quantitative PCR. Transcript levels were correlated with clinicopathological data. Higher levels of A-type lamins and LMNB1 mRNA expression were seen in ANCT. Higher lamin A/C expression was associated with the early clinical stage (TNM1 vs. TNM3 - 13 vs. 0.21; p = 0.0515), with better clinical outcomes (disease-free survival vs. mortality - 11 vs. 1; p = 0.0326), and with better overall (p = 0.004) and disease-free survival (p = 0.062). The expression of LMNB1 declined with worsening clinical outcome (disease-free vs. mortalities - 0.0011 vs. 0.000; p = 0.0177). LBR mRNA expression was directly associated with tumor grade (grade 1 vs. grade 3 - 0.00 vs. 0.00; p = 0.0479) and Nottingham Prognostic Index (NPI1 vs. NPI3 - 0.00 vs. 0.00; p = 0.0551). To the best of our knowledge, this is the first study to suggest such a role for A-type lamins, lamin B1 and LBR in human breast cancer, identifying an important area for further research.

Observations on the effects of Suppressor of Cytokine Signaling 7 (SOCS7) knockdown in breast cancer cells: their in vitro response to Insulin Like Growth Factor I (IGF-I)

PURPOSE

Suppressor of cytokine signaling 7 (SOCS7) is a member of the SOCS family and is known to interact with phospholipase Cγ-1 (PLCγ-1), one of the insulin-like growth factor-I (IGF-I) receptor downstream molecules. In this study, we sought to observe the effect of knocking down SOCS7 gene on breast cancer cells in vitro growth and migration and to elucidate whether this involves IGF-I-PLCγ1 route using the PLCγ-1 blocker U73122.

METHODS

Suitable breast cancer cells (MCF7 and MDA-MB-231) were transfected with anti-SOCS7 ribozymal transgene, to create sub-lines with SOCS7 knockdown verified by RT-PCR. The growth and migration of the cells were evaluated in the presence or absence of IGF-I and PLCγ-1 inhibitor using growth assay, scratch-wound and electrical cell impedance sensing (ECIS) migration assays.

RESULTS

IGF-I treatment produced more pronounced influence on MCF7 growth and migration and on MDA-MB-231 migration when SOCS7 gene was knocked down in both lines (p < 0.05). The absence of IGF-I-induced growth response in MDA-MB-231 could be due to the intrinsic characteristics of these cells. PLCγ-1 pharmacological inhibition during their in vitro migration seemed to only occur when SOCS7 gene was knocked down.

CONCLUSIONS

To the best of our knowledge, this is the first report of the SOCS7 regulatory role in IGF-I induced in vitro functions in ER-positive and ER-negative breast cancer cells. IGF-I treatment and SOCS7 loss have synergistically resulted in increased growth and migration of MCF7 and in increased migration of MDA-MB-231 cells. The migratory effects could be due to a precise anti-PLCγ-1 role.

The mRNA expression of inhibitors of DNA binding-1 and -2 is associated with advanced tumour stage and adverse clinical outcome in human breast cancer

Inhibitors of DNA binding (ID) are known to have a role in embryogenesis and oncogenesis. In this study, we analyzed the role of ID1 and ID2 in breast cancer, by assessing associations of mRNA expression with clinicopathological parameters.

MATERIALS AND METHODS

Breast cancer tissues (n=152) and adjacent normal tissues (n=31) underwent reverse transcription and quantitative- polymerase chain reaction (qPCR). Transcript levels were correlated with clinicopathological data.

RESULTS

Patients who were disease-free had significantly lower ID1 mRNA expression than all other patients (p=0.0033). Higher expression was associated with worse disease-free (p=0.001) and overall survival (p=0.02). ID2 expression was directly associated with the Nottingham Prognostic Index (NPI) (NPI 2 vs. 3; p=0.0062) and worsening clinical outcome (disease-free vs. mortality: p=0.0004), and with worse disease-free (p=0.01) and overall survival (p=0.005).

CONCLUSION

Our findings are suggestive of a role for ID1 and ID2 in human breast cancer as possible prognostic markers and therapeutic targets meriting further validating investigations, by immunohistochemistry and mechanistic studies.

P14ARF is down-regulated during tumour progression and predicts the clinical outcome in human breast cancer

The objective of this study was to determine the mRNA expression for p14 and p16 in a cohort of women with breast cancer.

MATERIALS AND METHODS

Breast cancer specimens (N= 127) and normal tissue (N=23) specimens were studied. Transcript levels were determined using quantitative polymerase chain reaction (PCR), and were correlated with clinicopathological data collected over 10 years.

RESULTS

Higher p14 mRNA transcript levels were associated with non-cancerous background tissue specimens (median copy numbers: 103 vs. 4, p=0.0095), with better overall and disease-free survival, and in TNM2 stage tumours (TNM2 vs. TNM1, 27.2 vs. 3.5, p=0.049; TNM1/TNM2 vs. TNM3/4, 26 vs. 2, p=0.009). There was no significant relationship between p16 levels and clinicopathological parameters. A correlation between p14 and human telomerase reverse transcriptase (hTERT) levels was observed (r=0.406, p=0.00005).

CONCLUSION

p14 expression seems to increase initially in early breast cancer and decrease with further tumour progression. p14 may be induced to counteract immortalisation and hTERT surge.

Prognostic and therapeutic implications of mTORC1 and Rictor expression in human breast cancer

The mammalian target of rapamycin (mTOR) plays a key role in the regulation of cellular metabolism, growth and proliferation. It forms two multi-protein complexes known as complex 1 (mTORC1) and 2 (mTORC2). Raptor and Rictor are the core proteins for mTORC1 and mTORC2, respectively. This study examines the relationship between mTORC1, Rictor and Raptor mRNA expression and human breast cancer. Furthermore, the correlation between mTORC1 and hTERT was investigated. Breast cancer tissues (n=150) and normal tissues (n=31) were analysed using reverse transcription and quantitative PCR. Transcript levels were correlated with clinicopathological data. Higher mTOR expression was noted in breast cancer tissue (P=0.0018), higher grade tumours (grade 2 vs. 3, P=0.047), in ductal tumours (P=0.0014), and was associated with worse overall survival (P=0.01). Rictor expression was significantly higher in background breast tissues compared with tumours and was inversely related to the Nottingham Prognostic Index (NPI1 vs. 2, P=0.03) and tumour grade (grade 1 vs. 3, P=0.01) and was associated with better overall (P=0.037) and disease-free survival (P=0.048). The mRNA expression of Raptor was higher in tumours compared with normal tissues. Furthermore, the expression of Raptor was associated with a higher tumour grade (grade 1 vs. 3, P=0.027). A highly significant positive correlation between mTOR and hTERT (P<0.00001) was observed. These observations are consistent with the role of mTORC1 in the anti-apoptosis pathway and suggest that selective inhibitors of mTORC1 may be more efficacious in human breast cancer. Our findings support the hypothesis that mTORC1 is an important upregulator of telomerase in breast cancer.

Guanine nucleotide binding protein β 1: a novel transduction protein with a possible role in human breast cancer

To our knowledge, this is the first study to examine the relationship between guanine nucleotide binding protein β-1 (GNB1) mRNA expression and clinicopathological parameters. Furthermore, the correlations between GNB1, Rictor and the mammalian target of rapamycin (mTOR) were also investigated.

MATERIALS AND METHODS

Breast cancer tissues (n=136) and normal tissues (n=31) underwent reverse transcription and quantitative polymerase chain reaction. Transcript levels were correlated with clinicopathological data.

RESULTS

Higher mRNA transcript levels of GNB1 were found in the breast cancer specimens in paired samples (p=0.0029). The mRNA expression of GNB1 increased with TNM stage (TNM1 vs. TNM2/3/4, p=0.036), tumour grade (grade 2 vs. 3, p=0.006), in ductal tumours (p=0.0081), and was associated with adverse patient outcomes (mortality vs. disease-free survival: 4.9 vs. 0.01, p=0.027). GNB1 was positively-correlated with mTOR (r=0.525, p<0.000001) and Rictor (r=0.388, p=0.0000606).

CONCLUSION

These observations may suggest that GNB1 plays an important role in the mTOR-related anti-apoptosis pathway and can potentially be targeted in the treatment of human breast cancer.

Abstract P1-04-07: The mRNA Expression of DAP1 in Human Breast Cancer: Correlation with Clinicopathological Parameters

BACKGROUND: This pilot study is the first to focus on the potential role for death-associated protein 1 (DAP1) in human breast cancer.

MATERIAL AND METHODS: mRNA expression of DAP1 in breast cancer tissues (n = 127) and normal background tissues (n = 33) were determined using quantitative polymerase chain reaction (qPCR) and correlated with clinicopathological data accumulated over a 10-year follow-up period. Furthermore the effects of DAP1 knockout in breast cancer cell lines were investigated.

RESULTS: The expression of DAP1 mRNA was demonstrated to decrease with increasing Nottingham Prognostic Index (NPI2 vs. NPI3, p = 0.0026), and TNM stage (TNM1 vs. 4, p = 0.0039). Lower DAP1 expression levels were significantly associated with local recurrence (p = 0.02) and distant metastasis (p = 0.001).

The knockout of the DAP1 gene in MCF-7 cell lines resulted in a significant decrease in the mRNA expression of P-21 and DELE compared with controls, p = 0.04). However, the knockout of DAP1 had no effect on the expression of caspase 8 and 9.

CONCLUSIONS: This study demonstrates an inverse association between DAP1 mRNA levels and tumour stage and clinical outcome in breast cancer. This may be suggestive of a relationship between oncogenesis and the autophagy pathway meriting further investigation. These results also indicate that the pro-apoptotic function seems to be estrogen-dependent but independent of caspase 8 and 9. The DAP1 pro-apoptotic pathway may involve P-21 and DELE proteins.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-04-07.

Abstract P1-04-08: Evidence for anti-apoptosis function of GNB1 in human breast cancer

INTRODUCTION: Guanine nucleotide binding protein beta polypeptide 1 (GNB1) integrates signals between receptors and effector proteins and regulates certain signal transduction receptors and effectors. We have hypothesised that GNB1 is involved in the anti-apoptosis pathway mediated by mTor. Therefore, this protein may play role in human carcinogenesis, however, there has been no investigations of this potential role published in the literature. The aim of the study was to investigate the mRNA expression of GNB1 in human breast cancer and examine the relationship between its expression and the tumour characteristics and disease outcome. Furthermore, the correlation between GNB1 and mTORC1 was also investigated.

METHODS: Specimens of breast cancer (BC) tissues (N = 136) and normal tissues (N = 30) underwent RNA extraction and reverse transcription. GNB1 transcript levels were determined using real-time quantitative PCR. Expression levels were analysed against clinicopathological data accrued over a 10 year follow-up period.

RESULTS: Significantly higher mRNA transcript levels were found in the breast cancer specimens compared to normal glandular tissue in paired samples (p = 0.0029). The expression of GNB1 mRNA was demonstrated to increase with increasing TNM stage (from 0.01 to 15.9) and this reached statistical significance when comparing TNM1 vs. TNM2/3/4 (p = 0.036). Furthermore, the expression levels increased with increasing tumour grade and this reached statistical significance when comparing grade 2 vs. grade 3 (p = 0.006). GNB1 expression was found to be higher in ductal tumours compared with non-ductal tumours (p = 0.0081). The patients who developed recurrent disease or died from breast cancer had higher expression levels than those who had been disease-free after a median follow-up period of 10 years (p = 0.017). Those who died from breast cancer had significantly higher levels than those who have remained disease-free (33.9 vs. 0.01, p = 0.0009). GNB1 showed a significantly positive correlation with mTORC1 mRNA levels (r = 0.57, p &lt; 0.000001).

CONCLUSION: GNB1 expression was found to be significantly higher in BC specimens compared to normal breast tissue. Higher transcript levels were significantly associated with unfavourable pathological parameters and adverse clinical outcomes. These observations in addition to the positive correlation with mTORC1 levels support the hypothesis that GNB1 is an important upstream component of the anti-apoptosis pathway and, therefore, can be a potential target for therapeutic intervention in human breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-04-08.

Abstract P1-04-03: Knocking down Suppressor of Cytokine Signaling 7 in breast cancer: The role in Insulin-like Growth Factor - I/Phospholipase Cγ-1 signaling

BACKGROUND: Suppressor of Cytokine Signaling 7 (SOCS7) is a member of the SOCS family and is known to interact with Phospholipase Cγ-1 (PLCγ-1), one of the Insulin like Growth Factor - I (IGF-I) receptor downstream molecules. In the present study, we sought to examine the effect of knocking down SOCS7 gene on breast cancer cells growth and migration and to elucidate whether this has involved IGF-I — PLCγ-1 signaling using the PLCγ-1 blocker U73122.

METHODS: Suitable breast cancer cells (MCF7 and MDA-MB-231) were transfected with anti-SOCS7 ribozymal transgene, to create sublines with SOCS7 knockdown that was verified by RT-PCR. The growth and migration of the cells were evaluated in the presence or absence of IGF-I and PLCγ-1 inhibitor using in vitro growth assay and Electrical Cell Impedance Sensing (ECIS) migration assay.

RESULTS: MCF7ΔSOCS7 and MDA-MB-231ΔSOCS7 (SOCS7 knockdown) were constructed. Both sublines showed a higher rate of growth compared to control cells with and without IGF-I stimulation. U73122 treatment did not appear to change this growth outcome. Using ECIS migration assay, it was shown that knocking down SOCS7 had a significant positive effect on the migration of MCF7 and MDA-MB-231 cells, and that both IGF-I treatment and SOCS7 knockdown had a synergistic positive influence on their migration (p &lt; 0.05). We further demonstrated that the impact of U73122 on the IGF-I migratory effect was dependent upon SOCS7 knockdown as it has significantly blocked the stimulatory effect of IGF-I on MCF7ΔSOCS7 and MDA-MB-231ΔSOCS7 migration but not that of the control cells. While SOCS7 has acted to control the IGF-I effect, it appeared to cancel the inhibitory function of U73122, indicating a specific anti - PLCγ-1 role for SOCS7 in IGF-I induced breast cancer cellular migration.

CONCLUSION: SOCS7 loss resulted in increased growth and migration of breast cancer cells and this had a synergistic effect on their response to IGF-I. This role could be related to its interaction with PLCγ-1 during the cellular migration but not the growth. It may be possible that SOCS7 acts through different mechanism to control the cellular growth.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-04-03.

Abstract P6-05-11: Leptin and Leptin receptor expression in human breast cancer

INTRODUCTION: Leptin is a protein that plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. It is one of the most important adipose derived hormones and has been suggested to act as a growth factor in neoplasms. Obesity has been linked to increased risk of breast cancer in postmenopausal women. Increased peripheral production of oestrogen has been regarded as the main cause for this association, but other factors affecting fat metabolism may be implicated. There is recent evidence that Leptin stimulates cancer cell proliferation in MCF-7 cancer cells. Both Cox2 and hTERT have been proposed as mediators of Leptin's carcinogenic role.

Our objective was to determine, using quantitative PCR, whether the mRNA expression levels of Leptin and Leptin receptor were consistent with a tumour proliferative function and whether levels from these genes were positively correlated with clinical outcome in breast cancer.

METHODS: A total of 153 samples were analysed. The levels of transcription of Leptin and its receptor were determined using quantitative PCR and normalised against (CK19). Transcript levels within breast cancer specimens were compared to normal background tissues and analysed against conventional pathological parameters and clinical outcome over a 10 year follow-up period.

RESULTS: The levels of Leptin and Leptin receptor mRNA were significantly higher in malignant samples (p = 0.0011 and 0.0014 respectively). This difference remained statistically significant when comparing levels between normal samples and all malignant subgroups according to their NPI, grade, stage, local recurrence, and distant metastasis in both ER receptor positive and negative samples. It was also present across all histological types for both Leptin and its receptor.

There was no significant change in mRNA transcription levels correlating with tumour grade, stage, disease free survival, or development of loco regional recurrence.

There was also no statistically significant difference in levels of expression of both Leptin and its receptor when comparing ER positive to negative patients (p = 0.74 and 0.27 respectively).

Leptin levels showed a significantly positive correlation with Leptin receptors (r = 0.504, 0.0000000222). We have observed no significant correlations between Leptin and hTERT or Cox2.

CONCLUSION: This study demonstrates compelling evidence that both Leptin and Leptin receptor mRNA transcription levels are more readily expressed in cancerous tissues providing further evidence that it plays a significant role in the process of breast carcinogenesis. However, Leptin levels did nor correlate with tumor's stage, clinical outcome, hTERT or Cox-2 levels.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-05-11.

Abstract P1-04-09: mTORC1 and Rictor expression in human breast cancer: correlations with clinicopathological parameters and disease outcome

BACKGROUND: mTOR (the mammalian target of rapamycin) plays a key role in regulation of cellular metabolism, growth, and proliferation. It forms two multi-protein complexes known as complex 1 (mTORC1) and 2 (mTORC2). Raptor and Rictor are the core proteins for mTORC1 and mTORC2 respectively. There is a growing body of evidence that mTORC1 is up-regulated in many cancers and plays a role in carcinogenesis. The aim of the study was to investigate the mRNA expression of mTOR and Rictor in human breast cancer and examine the relationship between their expression and clinicopathological parameters.

METHODS: Specimens of breast cancer (BC) tissues (N = 150) and normal tissues (N = 31) underwent RNA extraction and reverse transcription. mTOR and Rictor transcript levels were determined using real-time quantitative PCR. Expression levels were analyzed against tumor size, grade, nodal involvement, TNM stage, and clinical outcome over a 10 year follow-up period.

RESULTS: Significantly higher mRNA transcript levels of mTOR were found in the breast cancer specimens compared to normal glandular tissue (p = 0.0018). The expression of mTOR mRNA was demonstrated to increase with increasing NPI (53 for NPI1 to 219 for NPI3) and tumor grade (37 for grade 2 vs. 159 for grade 3, p = 0.047). mTOR expression was found to be higher in ductal tumors compared with non-ductal tumors (p = 0.0014). The patients who developed recurrent disease or died from breast cancer had higher expression levels than those who had been disease-free after a median follow-up period of 10 years (p = 0.17). Higher expression levels were significantly associated with worse overall survival (p = 0.01).

In contrast, higher levels of Rictor mRNA expression were found in normal breast tissue, lower NPI stage (NPI1 vs. 2: p = 0.03) and lower tumor grade (grade 1 vs. grade 3: p = 0.01). Patients with higher Rictor expression had a significantly better overall (p = 0.037) and disease-free (p = 0.048) survival.

CONCLUSIONS: mTOR expression was found to be significantly higher in BC specimens compared to normal breast tissue. Higher transcript levels were significantly associated with unfavorable pathological parameters and adverse clinical outcomes. The core protein of the less predominant mTORC2 was associated with favorable pathological parameters and clinical outcome. Taken together these observations are consistent with mTORC1 role in the anti-apoptosis pathway and suggest that selective inhibitors of mTORC1 are likely to be a more effective therapeutic strategy than dual inhibitors in human breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-04-09.

Evidence of an autocrine role for leptin and leptin receptor in human breast cancer

We studied potential associations between the expression of leptin, leptin receptor (LEPR) and clinicopathological parameters of breast cancer, and the correlation of leptin with human telomerase reverse transcriptase (hTERT) and cyclooxygenase 2 (COX2)

PATIENTS AND METHODS

A total of 153 specimens were studied. Transcript levels were determined using quantitative polymerase chain reaction (qPCR), and were correlated with clinicopathological data collected for over 10 years. Additionally, leptin and LEPR expression was studied in several breast cell lines.

RESULTS

Both leptin and LEPR mRNA expression were higher in malignant samples (p=0.0011 and 0.0014 respectively). Both were also expressed in MDA436 and MCF7 cell lines. Leptin showed a significant correlation with LEPR (r=0.504, p=0.0000000222). Leptin did not correlate significantly with clinical stage, tumour grade, or with the expression of hTERT or COX2.

CONCLUSIONS

This study demonstrates that leptin and LEPR are more readily expressed in cancerous tissues suggesting a possible autocrine role in mammary carcinogenesis, which may be independent of hTERT and COX2 genes.

The mRNA expression of DAP1 in human breast cancer: correlation with clinicopathological parameters

This pilot study is the first to focus on the potential role of death-associated protein 1 (DAP1) in human breast cancer.

MATERIALS AND METHODS

A total of 153 samples were studied. DAP1 transcription levels were determined using quantitative polymerase chain reaction (qPCR). Transcript levels within breast cancer specimens were compared to those of normal background tissues and correlated with clinicopathological data accumulated over a 10-year follow-up period.

RESULTS

The expression of DAP1 mRNA was demonstrated to decrease with increasing Nottingham Prognostic Index (NPI2 vs. NPI3, p=0.0026), and TNM stage (TNM1 vs. 4, p=0.0039). Lower DAP1 expression levels were significantly associated with local recurrence (p=0.02) and distant metastasis (p=0.001).

CONCLUSION

This study demonstrates an inverse association between DAP1 mRNA levels and tumour stage and clinical outcome in breast cancer; thus, providing evidence that DAP1 plays a pro-apoptotic role in human breast cancer. The relationship between oncogenesis and the autophagy pathway merits further investigation.

Ductal carcinoma in situ: recent advances and future prospects

Introduction. This article reviews current management strategies for DCIS in the context of recent randomised trials, including the role of sentinel lymph node biopsy (SLNB), adjuvant radiotherapy (RT) and endocrine treatment. Methods. Literature review facilitated by Medline, PubMed, Embase and Cochrane databases. Results. DCIS should be managed in the context of a multidisciplinary team. Local control depends upon clear surgical margins (at least 2 mm is generally acceptable). SLNB is not routine, but can be considered in patients undergoing mastectomy (Mx) with risk factors for occult invasion. RT following BCS significantly reduces local recurrence (LR), particularly in those at high-risk. There remains a lack of level-1 evidence supporting omission of adjuvant RT in selected low-risk cases. Large, multi-centric or recurrent lesions should be treated by Mx and immediate reconstruction should be discussed. Adjuvant hormonal treatment may reduce the risk of LR in selected cases with hormone sensitive disease. Conclusion. Further research is required to determine the role of new RT regimes and endocrine therapies. Biological profiling and molecular analysis represent an opportunity to improve our understanding of tumour biology in DCIS to rationalise treatment. Reliable identification of low-risk lesions could allow treatment to be less radical.

The mRNA expression of DAP3 in human breast cancer: correlation with clinicopathological parameters

BACKGROUND

This pilot study is the first to focus on the potential role for death-associated protein 3 (DAP3) in human breast cancer.

MATERIALS AND METHODS

A total of 153 samples were studied. The levels of transcription of DAP3 were determined using quantitative polymerase chain reaction (qPCR). Transcript levels within breast cancer specimens were compared to those of normal background tissues and correlated with clinicopathological data accumulated by over a 10-year follow-up period.

RESULTS

The expression of DAP3 mRNA was demonstrated to decrease with increasing Nottingham Prognostic Index (NPI2 vs. 3, p=0.036), TNM stage (TNM1 vs. 3, p=0.07), and tumour grade (grade 1 vs. 3, p=0.08). Lower DAP3 expression levels were significantly associated with local recurrence (p=0.013), distant metastasis (p=0.0057) and mortality (p=0.019).

CONCLUSION

This study demonstrates an inverse association between DAP3 mRNA levels and tumour stage and clinical outcome in breast cancer, consistent with the pro-apoptosis function of DAP3. Further research is required in order to confirm our findings and clarify the mechanisms that regulate DAP3 expression in human breast cancer.

Does post-mastectomy radiotherapy represent a contraindication to skin-sparing mastectomy and immediate reconstruction: an update

The use of skin-sparing mastectomy (SSM) to facilitate breast reconstruction is increasing due to a wide acceptance of improved cosmetic outcomes and evidence of equivalence in oncologic outcomes. The rates of patients undergoing mastectomy for whom post-mastectomy radiotherapy (PMRT) will be recommended is increasing as evidence of decreased loco-regional recurrence and increased survival mounts. PMRT may adversely effect complication rates and cosmetic outcomes for patients undergoing immediate breast reconstruction and PMRT--although the evidence for this is methodologically flawed. This article summarises the above evidence and highlights a reconstructive algorithm that may be used to mitigate the possible deleterious effects of PMRT on results.

P2-11-02: Brain-Derived Neurotrophic Factor Expression Is Associated with Poor Prognosis in Human Breast Cancer

Background: Brain-derived neurotrophic factor (BDNF) belongs to the neurotrophin superfamily of polypeptide growth factors whose physiological roles primarily relate to the development and function of the vertebrate nervous system. However, BDNF is also expressed in non-neuronal tissues and has been implicated in breast cancer, in addition to several other human malignancies, including: neuroblastoma, myeloma, ***ovarian, lung, prostate, hepato-cellular, pancreatic, head and neck squamous cell carcinomas and pulmonary carcinoid tumours. Although increased neurotrophin and cognate receptor expression have been demonstrated in breast cancer, the emerging role of BDNF in tumour biology and its utility as a novel biomarker have yet to be fully elucidated. In this study, the mRNA and protein expression of BDNF are evaluated in women with primary operable breast cancer in a well annotated cohort with extended follow-up.

Methods: Breast cancer tissues (n=127) and normal/benign tissues (n=33) underwent RNA extraction and reverse transcription. Transcript levels of BDNF were determined using real-time quantitative PCR and protein expression was assessed using standardised semi-quantitative immuno-histochemical techniques. Expression levels in neoplastic tissues were compared with adjacent normal/benign samples and evaluated against conventional pathological parameters, including: tumour size, grade, nodal involvement, TNM stage, in addition to Nottingham Prognostic Index (NPI), disease free and overall survival over a 10 year follow-up period.

Results: BDNF was found to be expressed in both normal breast tissue and breast cancer specimens. Significantly greater BDNF expression was identified in neoplastic cells, compared to normal mammary epithelial cells, by immuno-histochemical analysis. In keeping with this, higher mRNA transcript levels of BDNF were also found in breast cancers compared to normal samples (p=0.007). Increased BDNF transcript levels were found to be significantly associated with nodal positivity (p=0.047) and increased with NPI; NPI-1 vs. NPI-2 (p=0.009). Higher BDNF expression was significantly associated with local recurrence (p=0.0014), death from breast cancer (p=0.018) and poor prognosis overall (p=0.013), when compared to patients who remained disease free. Higher transcript levels were significantly associated with poorer overall survival (106 vs. 136 months, p=0.006) after a median follow up of 10 years.

Conclusion: Neurotrophins and their receptors are increasingly being implicated as novel mediators of carcinogenesis in neuronal and non-neuronal tissues. BDNF is overexpressed in breast cancer and significantly associated with adverse pathological parameters, including nodal positivity and increasing NPI. Higher BDNF expression was significantly associated with poorer clinical outcomes, including local recurrence, death, poor prognosis and reduced overall survival. The present study adds to the literature in support of the oncogenic function of BDNF in breast cancer and is the first to quantitatively evaluate expression in a large cohort. BDNF expression may offer prognostic utility as a biomarker and further mechanistic studies are warranted to explore the potential for targeted therapeutic manipulation.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-11-02.

P1-05-05: Prognostic Utility of Histone Modifier Gene Expression Profiles in Human Breast Cancer

Background: Gene expression is stringently controlled under physiological conditions by epigenetic mechanisms, including the specific methylation of cytosine residues within CpG dinucleotides and orchestrated adjustments in the histone dependent organisation of chromatin. The organisation of DNA within the chromatin template depends upon highly conserved histone proteins, the properties of which continue to exceed the simplistic packaging role originally assigned to them. Histone modifier enzymes impart a dynamic histone code and specific permutations have significant implications for chromatin topology and the functional configuration of promoters. This study follows our initial report describing potential tumour suppressor function associated with the histone methyltransferase SETD2 in human breast cancer. The objective was to evaluate the expression profiles of sixteen additional histone modifier genes in women with primary operable breast cancer within a well annotated cohort with extended follow-up.

Methods: Primary breast cancer tissues (n= 127) and adjacent benign/normal tissues (n=33) underwent RNA extraction and reverse transcription. The transcript levels of histone modifier genes were evaluated using real-time quantitative PCR, these included: histone acetyltransferases (CREBBP), Class 1 (HDAC1 and HDAC2), II (HDAC5) and III (SIRT1) histone deacetylases and histone methyltransferases (SUV39H1 and SUV39H2) amongst others. Transcript levels were analysed against a range of clinico-pathological variables, including: tumour size, grade, nodal involvement, histological subtype, receptor status, TNM stage, Nottingham Prognostic Index, disease free and overall survival over a 10 year follow-up period.

Results: Transcript levels of the histone modifier genes in breast cancer tissues differed significantly from non-malignant samples (HDAC5, HDAC1, KDM4A and KDM6A). Amongst breast cancers, significant differences in transcript levels were associated with established pathological parameters and prognostic indices: tumour grade (KAT5, HDAC1, KDM4A, SUV39H1 and KDM6A), receptor status (KAT5, SMYD3 and KDM1A), histological type (KAT5, KDM5C, MYST1, KDM4A and MLL), TNM stage (SUV39H1, KAT2B, KDM1A, KDM4A, KDM5C, MYST1, HDAC5 and KAT5), Nottingham Prognostic Index (KDM5C, MLL, MYST1 and SMYD3), disease free survival (SUV39H1, SMYD3, HDAC5, KDM6A, HDAC1, KDM1A, KDM4A, MYST1, KDM5C, KAT5 and MLL) and overall survival (MYST1). Interestingly, significant correlations were also identified between the differential expression profiles of particular histone modifying genes.

Conclusion: The expression profiles of histone modifier genes differ significantly between breast cancer tissues and normal/benign samples. Particular expression profiles in breast cancer are significantly associated with established pathological parameters, prognostic indices, disease free and overall survival. The biological significance and clinical relevance of altered expression of specific histone modifier genes and particular permutations of misexpression remain to be fully elucidated and further study is warranted. Epigenetic signatures derived from histone modifier genes may offer utility as biomarkers and histone modifier enzymes have potential for targeted therapeutic strategies.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-05-05.

Histone-modifier gene expression profiles are associated with pathological and clinical outcomes in human breast cancer

BACKGROUND

Epigenetic regulation of gene expression is under normal circumstances tightly controlled by the specific methylation of cytosine residues in CpG dinucleotides and coordinated by adjustments in the histone-dependent configuration of chromatin. Following our original report, providing the first description of potential tumor suppressor function associated with the histone methyltransferase SET domain containing 2 (SETD2) in breast cancer, the objective of this study was to determine the expression profiles of 16 further histone-modifier genes in a well annotated cohort of patients with primary operable breast cancer.

MATERIALS AND METHODS

Breast cancer tissues (n=127) and normal tissues (n=33) underwent RNA extraction and reverse transcription, and histone-modifier gene transcript levels were determined using real-time quantitative PCR. The histone-modifier genes included: histone acetyltransferases (cAMP response element-binding protein-binding protein (CREBBP)); class I (histone deacetylase 1 (HDAC1) and histone deacetylase 2 (HDAC2)), II (histone deacetylase 5 (HDAC5)) and III (sirtuin 1 (SIRT1)) histone deacetylases; and histone methyltransferases (SET domain containing suppressor of variegation 3-9 homolog 1 (SUV39H1) and suppressor of variegation 3-9 homolog 2 (SUV39H2)) amongst others. Expression levels were analysed against tumor size, grade, nodal involvement, histological subtype, receptor status, TNM stage, Nottingham Prognostic Index, and disease-free and overall survival over a 10-year follow-up period.

RESULTS

Expression of histone-modifier genes in breast cancer differed significantly from those in normal tissue (HDAC5, HDAC1, lysine (K)-specific demethylase 4A (KDM4A) and lysine (K)-specific demethylase 6A (KDM6A)). Differences in expression profiles were also found to exist between individual breast tumors and, in some cases, were significantly associated with conventional pathological parameters and prognostic indices: tumor grade (K (lysine) acetyltransferase 5 (KAT5), HDAC1, KDM4A, SUV39H1 and KDM6A)); TNM stage (SUV39H1, K (lysine) acetyltransferase 2B (KAT2B), lysine (K)-specific demethylase 1A (KDM1A), KDM4A, lysine (K)-specific demethylase 5C (KDM5C), K (lysine) acetyltransferase 8 (KAT8), HDAC5 and KAT5)); Nottingham Prognostic Index (KDM5C, myeloid/lymphoid or mixed-lineage leukemia (MLL), KAT8 and SET and MYND domain containing 3 (SMYD3)); receptor status (KAT5, SMYD3 and KDM1A); histological type (KAT5, KDM5C, KAT8, KDM4A and MLL); disease-free survival (SUV39H1, SMYD3, HDAC5, KDM6A, HDAC1, KDM1A, KDM4A, KAT8, KDM5C, KAT5 and MLL) and overall survival (KAT8). Significant correlations were identified between the differential expression profiles of particular histone-modifying genes.

CONCLUSION

Expression levels of histone-modifier genes in breast cancer differ significantly from normal tissue. Differences in expression profiles exist between breast tumors and are significantly associated with conventional pathological parameters and clinical outcomes. Further study is warranted to determine the consequences of altered expression for each specific histone-modifier gene and the biological and clinical implications of combinatorial variations in expression profiles. Histone-modifier enzymes offer utility as biomarkers and potential for targeted therapeutic strategies.

Sentinel lymph node micrometastasis in human breast cancer: an update

INTRODUCTION

The advent of sentinel lymph node biopsy (SLNB) and advances in histopathological and molecular analysis techniques have been associated with an increase in micrometastasis (MM) detection rate. However, the clinical significance of sentinel lymph node micrometastasis (SLN MM) continues to be a subject of much debate. In this article we review the literature concerning SLN MM, with particular emphasis on the prognostic significance of SLN MM. The controversies regarding histopathological assessment, clinical relevance and management implications are also discussed.

METHODS

Literature review facilitated by Medline and PubMed databases. Cross referencing of the obtained articles was used to identify other relevant studies.

RESULTS

Published studies have reported divergent and rather conflicting results regarding the clinical significance and implications of axillary lymph node (ALN) MM in general and SLN MM in particular. Some earlier studies demonstrated no associations, however most recent studies have found SLN MM to be an indicator of poorer prognosis and to be associated with non-SLN involvement. The use of adjuvant chemotherapy and/or hormonal manipulation therapy is associated with an improved survival in patients with SLN MM. Complete ALND may be safely omitted provided that adjuvant systemic therapy recommendations are equal to patients with node-positive disease. However, optimal management of SLN MM is yet to conclude. Furthermore, the identification of MM remains largely dependent on the analytical technique employed and the use of immunohistochemistry (IHC) increases the detection rate of SLN MM. Discrepancies in the histopathological interpretation of TNM classification of SLN tumour burden do exist. Published studies were non-randomized and have significant limitations including a small sample size, limited follow-up period, and lack of standardization and reproducibility of pathological examination of the SLN.

CONCLUSION

Patients with SLN MM have a poorer prognosis than those who are SLN negative. Therapeutic recommendations regarding patients with SLN MM should be taken in the context of multidisciplinary team setting and in selected cases of SLN MM, complete ALND may be safely omitted. A better reproducibility of pathological interpretation of the TNM classification is required so that future therapeutic guidelines can be applied without confusion.

Brain-derived neurotrophic factor expression predicts adverse pathological & clinical outcomes in human breast cancer

Introduction

Brain-derived neurotrophic factor (BDNF) has established physiological roles in the development and function of the vertebrate nervous system. BDNF has also been implicated in several human malignancies, including breast cancer (BC). However, the precise biological role of BDNF and its utility as a novel biomarker have yet to be determined. The objective of this study was to determine the mRNA and protein expression of BDNF in a cohort of women with BC. Expression levels were compared with normal background tissues and evaluated against established pathological parameters and clinical outcome over a 10 year follow-up period.

Methods

BC tissues (n = 127) and normal tissues (n = 33) underwent RNA extraction and reverse transcription, BDNF transcript levels were determined using real-time quantitative PCR. BDNF protein expression in mammary tissues was assessed with standard immuno-histochemical methodology. Expression levels were analyzed against tumour size, grade, nodal involvement, TNM stage, Nottingham Prognostic Index (NPI) and clinical outcome over a 10 year follow-up period.

Results

Immuno-histochemical staining revealed substantially greater BDNF expression within neoplastic cells, compared to normal mammary epithelial cells. Significantly higher mRNA transcript levels were found in the BC specimens compared to background tissues (p = 0.007). The expression of BDNF mRNA was demonstrated to increase with increasing NPI; NPI-1 vs. NPI-2 (p = 0.009). Increased BDNF transcript levels were found to be significantly associated with nodal positivity (p = 0.047). Compared to patients who remained disease free, higher BDNF expression was significantly associated with local recurrence (LR) (p = 0.0014), death from BC (p = 0.018) and poor prognosis overall (p = 0.013). After a median follow up of 10 years, higher BDNF expression levels were significantly associated with reduced overall survival (OS) (106 vs. 136 months, p = 0.006). BDNF emerged as an independent prognostic variable in multivariate analysis for disease free survival (DFS) (p = 0.026) and approached significance for OS (p = 0.055).

Conclusion

BDNF expression was found to be significantly higher in BC specimens compared to normal tissue. Higher transcript levels were significantly associated with unfavourable pathological parameters including nodal positivity and increasing NPI; and adverse clinical outcomes including LR, death from BC, poor prognosis, reduced DFS and OS. BDNF offers utility as a prognostic marker and potential for targeted therapeutic strategies.

The prognostic significance of the insulin-like growth factor-1 ligand and receptor expression in breast cancer tissue

BACKGROUND AND OBJECTIVES

Previous in vitro studies have suggested that IGF-1 stimulation can lead a more aggressive breast cancers and subsequent poor prognosis in breast cancer patients. We aim to how IGF-1 and IGF-1R mRNA levels in breast cancer are associated with disease-free survival (DFS) and other clinicopathological factors.

METHODS

IGF-1 and IGF-1R mRNA levels were measured in breast cancer tissue from 132 patients using real-time PCR. DFS and clinicopathological information were obtained from patient case notes.

RESULTS

IGF-1 and IGF-1R mRNA levels did not correlate with any clinicopathological factors. Patients who relapsed had lower IGF-1 mRNA levels in their tumour tissue compared to those who remained disease-free during the 5-year follow-up period. Patients who had ER-positive breast cancers with high IGF-1 mRNA levels had longer DFS compared to those with low IGF-1 mRNA levels. IGF-1 mRNA levels was not associated with DFS in patients with ER-negative cancers. IGF-1R mRNA levels was not associated with DFS in any subgroup analysis. Multivariate analysis showed that IGF-1 mRNA levels and histopathological grade were independent predictors of DFS.

CONCLUSIONS

Breast cancer tissue IGF-1 expression is a favourable prognostic indicator and could be used in clinical setting in planning for adjuvant treatment.

Measuring IGF-1, ER-α and EGFR expression can predict tamoxifen-resistance in ER-positive breast cancer

In vitro studies have suggested that tamoxifen resistance may be due to altered expression and downstream signalling of insulin-like growth factor-1 (IGF-1) receptor (IGF-1l), oestrogen receptor-alpha (ERα), epidermal growth factor receptor (EGFR) and HER-2. We investigated which gene expressions could predict tamoxifen resistant breast cancer. Expression of IGF-1R, IGF-1 ligand (IGF-1), ERα, EGFR and HER-2 in 91 ER-positive breast cancer tumours were measured using real-time PCR and correlated with clinical outcome. The tamoxifen resistant group (n=20) consisted of: i) tumours which were resistant to neoadjuvant tamoxifen treatment and ii) tumours which were excised from patients who later developed recurrence or metastasis during adjuvant tamoxifen treatment. These were compared with tamoxifen sensitive tumours which were surgical excision specimens from patients who did not develop recurrence/metastasis during adjuvant tamoxifen treatment. Tumours with higher IGF-1 ligand and ERα expression took longer to develop tamoxifen resistance. Tamoxifen resistant tumours had lower IGF-1 and ERα expression compared to tamoxifen-sensitive tumours. IGF-1 expression strongly correlated with ERα expression in the tamoxifen sensitive group only. ERα inversely correlated with EGFR expression in the tamoxifen resistant group only. We conclude that IGF-1 ligand and ERα expression in breast carcinomas can be measured to predict tamoxifen resistance. Measuring ERα expression using RT-PCR may be more sensitive than immunohistochemistry in determining anti-oestrogen sensitivity.

Ductal carcinoma in-situ: an update for clinical practice

INTRODUCTION

Ductal carcinoma in-situ (DCIS) is a heterogeneous entity with an elusive natural history. The objective of radiological, histological and molecular characterisation remains to reliably predict the biological behaviour and optimise clinical management strategies. Increases in diagnostic frequency have followed the introduction of mammographic screening and increased utility of magnetic resonance imaging. However, progress remains limited in distinguishing non-progressive incidental lesions from their progressive and clinically relevant counterparts. This article reviews current management strategies for DCIS in the context of recent randomized trials, including the role of sentinel lymph node biopsy (SLNB), adjuvant radiotherapy (RT) and endocrine treatment.

METHODS

Literature review facilitated by Medline, PubMed, Embase and Cochrane databases.

RESULTS

DCIS should be managed in the context of a multidisciplinary team. Local control depends upon adequate surgical clearance with margins of at least 2 mm. SLNB is not routinely indicated and should be reserved for those with concurrent or recurrent invasive disease. SLNB can be considered in patients undergoing mastectomy (MX) and those with risk factors for invasion such as palpability, comedo morphology, necrosis or recurrent disease. RT following BCS significantly reduces local recurrence (LR), particularly in those at high-risk. There remains a lack of level-1 evidence supporting the omission of adjuvant RT in selected low-risk cases. Large, multi-centric or recurrent lesions (particularly in cases of prior RT) should be treated by MX with the opportunity for immediate reconstruction. Adjuvant Tamoxifen may reduce the risk of LR in selected cases with hormone sensitive disease.

CONCLUSION

Further research is required to determine the role of contemporary RT regimes and endocrine therapies. Biological profiling and molecular analysis represent an opportunity to improve our understanding of the tumour biology of this condition and rationalise its treatment. Reliable identification of low-risk lesions could allow treatment to be less radical or safely omitted.

Prognostic implications of carboxyl-terminus of Hsc70 interacting protein and lysyl-oxidase expression in human breast cancer

Background:

Ubiquitin modification of proteins influences cellular processes relevant to carcinogenesis. CHIP (carboxyl-terminus of Hsc70-interacting protein) is a chaperone-dependent E3 ubiquitin ligase, regulating the stability of heat shock protein 90 (HSP90) interacting proteins. CHIP is implicated in the modulation of estrogen receptor (ESR1) and Her-2/neu (ERBB2) stability. LOX (lysyl-oxidase) serves intracellular roles and catalyses the cross-linking of extracellular matrix (ECM) collagens and elastin. LOX expression is altered in human malignancies and their peri-tumoral stroma. However, paradoxical roles are reported. In this study, the level of mRNA expression of CHIP and LOX were assessed in normal and malignant breast tissue and correlated with clinico-pathological parameters.

Materials and Methods:

Breast cancer (BC) tissues (n = 127) and normal tissues (n = 33) underwent RNA extraction and reverse transcription; transcript levels were determined using real-time quantitative PCR and normalized against CK-19. Transcript levels were analyzed against TNM stage, nodal involvement, tumor grade and clinical outcome over a ten-year follow-up period.

Results:

CHIP expression decreased with increasing Nottingham Prognostic Index (NPI): NPI-1 vs. NPI-3 (12.2 vs. 0.2, P = 0.0264), NPI-2 vs. NPI-3 (3 vs. 0.2, P = 0.0275). CHIP expression decreased with increasing TNM stage: TNM-1 vs. TNM-2 (12 vs. 0, P = 0.0639), TNM-1 vs. TNM-2-4 (12 vs. 0, P = 0.0434). Lower transcript levels were associated with increasing tumor grade: grade 1 vs. grade 3 (17.7 vs. 0.3, P = 0.0266), grade 2 vs. grade 3 (5 vs. 0.3, P = 0.0454). The overall survival (OS) for tumors classified as ‘low-level expression’, was poorer than those with ‘high-level expression’ (118.1 vs. 152.3 months, P = 0.039). LOX expression decreased with increasing NPI: NPI-1 vs. NPI-2 (3 vs. 0, P = 0.0301) and TNM stage: TNM-1 = 3854639, TNM-2 = 908900, TNM-3 = 329, TNM-4 = 1.232 (P = NS).

Conclusion:

CHIP expression is associated with favorable prognostic parameters, including tumor grade, TNM stage and NPI. CHIP expression predicts OS. LOX expression is associated with improved NPI. In addition to their prognostic utility, mechanistic insights into tumor suppressor function may offer potential therapeutic strategies.