Retrospective analysis of treatment, including access to breast reconstructions, of breast cancer patients - war refugees from Ukraine in Poland - the experience of a single tertiary care institution

<b>Introduction:</b> Following the Russian invasion, more than 3600000 refugees have fled Ukraine and settled down in Poland; this group includes a growing number of breast cancer patients whose treatment had been started in Ukraine and hence required urgent therapy in Poland.</br></br> <b>Aim:</b> The aim of the study was to analyze the treatment of breast cancer patients from Ukraine, who entered Poland as war refugees - the experience of a single tertiary care institution.</br></br> <b>Material and methods:</b> The treatment of 25 consecutive breast cancer patients, war refugees from Ukraine was reviewed retrospectively.</br></br> <b>Results:</b> Patients were treated according to subtype and staging, e.g. surgery, endocrine, anti-HER2 therapy, chemotherapy, radiotherapy. 7 patients received an immediate implant, mesh-based breast reconstruction. In 2 cases, the patients refused breast reconstruction.</br></br> <b>Conclusions:</b> Nearly 5.5 million refugees across Europe who have fled the combat zones in Ukraine; of these, the vast majority sought shelter in Poland, and many of whom are women. It is expected that breast cancer mortality rates may rise and progress in oncology may slow as the war in Ukraine disrupts routine patient care, clinical trials and research. Hence, support from neighboring countries is mandatory.

Assessment of the use of the Magseed marker in the localization of non-palpable lesions in the mammary gland

Introduction Currently, more and more cases of breast cancer are detected in the early stages of advancement. Removal of the minimum required tissue volume ensures that the proper shape of the breast is maintained. On the other hand, it is important to get negative tissue margins. Objective To present your own experience with the use of preoperative breast tumor determination using the Magseed marker. Material and methods On the eve of the procedure, a Magtrace magnetic marker was administered to determine the lymph nodes and, under ultrasound control, a Magseed magnetic marker to the tumor, and the site of the lesion was marked with a skin marker as the operated site. Before the skin incision, the lesion was located using intraoperative ultrasound and the Sentimag probe. After the tumor was excision, the presence of the marker was confirmed in the preparation using the magnetic method and the compatibility of the ultrasound image before and after the procedure. The results of the research group were 23 patients. Radicality of the procedure was achieved in 20 patients (87%). To assess the size of the preparation and tumor, a formula from the work of Angarita et al. on the volume of the ellipsoid was used. It was assessed what part of the excised preparation was a tumor marked using the Magseed marker. Cohorts of 11 patients at the beginning and end of the evaluated group were compared, showing a significant increase in this parameter. Together with the learning curve, you can identify the tumor much more precisely and save healthy breast tissues by improving the aesthetic effect in the breast range. Conclusions The method of localization of non-pallpatory lesions in the mammary gland using the Magseed marker is simple to use, and the high detection rate directly translates into a reduction in the percentage of non-radical treatments in the case of sparing treatment.

ECCO Essential Requirements for Quality Cancer Care: Primary care

BACKGROUND

ECCO Essential Requirements for Quality Cancer Care (ERQCC) are checklists and explanations of organisation and actions that are necessary to give high-quality care to cancer patients. They are written by European experts representing all disciplines involved in cancer care. This paper concerns the integration of primary care into care for all cancers in Europe. Primary care integration.

The current application of ACOSOG Z0011 trial results: Is further implementation of sentinel lymph node intra-operative histopathological examination mandatory in breast cancer patients - a single-centre analysis

The main objective of the ACOSOG Z0011 trial was to determine the impact of abandoning complete axillary lymph node dissection (ALND) on survival of breast cancer patients with sentinel node lymph (SLN) metastasis in whom breast conserving therapy (BCT) had been performed. The aim of our study was to assess the clinical value of intra-operative histopathological examination of SLN. Our study comprised 1284 invasive breast cancer patients in whom sentinel lymph node biopsy (SLNB) was carried out. SLN intra-operative histopathological assessment was routinely performed in patients treated within the first period (07.2013-06.2014). However, the decision regarding intra-operative assessment was made by the surgeon for the patients who underwent this evaluation in the later period 07.2014-06.2015 and were submitted for BCT. BCT was performed in 72.4% of patients. In total, 316 patients (24.6%) developed SLN-metastasis. Within the period 07.2014-06.2015, SLN intra-operative microscopic evaluation was performed in 20.8% of patients submitted for BCT. ALND was omitted in 27.5% of patients demonstrating SLN metastasis, in comparison with 15.5% of the group from the previous period (p=0.0094). The proportion of patients demonstrating macrometastasis in SLN who received conservative treatment to the axilla increased from 5.4% to 23.1% (p=0.0007). The choice of SLN final histopathological assessment may allow for deferral of decision on more extensive surgery of the axilla in patients submitted for SLNB. The omission of routinely-performed SLN intra-operative histopathological evaluation has led to a statistically significant increase in the proportion of patients in whom complete ALND was avoided.

European Society of Surgical Oncology's strategy for clinical research: Paving the way for a culture of research in cancer surgery

As part of its mission to promote the best surgical care for cancer patients, the European Society of Surgical Oncology (ESSO) has been developing multiple programmes for clinical research along with its educational portfolio. This position paper describes the different research activities of the Society over the past decade and an action plan for the upcoming five years to lead innovative and high quality surgical oncology research. ESSO proposes to consider pragmatic research methodologies as a complement to randomised clinical trials (RCT), advocates for increased funding and operational support in conducting research and aims to enable young surgeons to be active in research and establish partnerships for translational research activities.

Immune checkpoints in aggressive breast cancer subtypes

Immune checkpoints are molecules referred to inhibitory pathways in the immune system that play a pivotal role in prevention of autoimmunity and oncogenesis. The aim of the study was to evaluate expression levels of selected immune checkpoints- PD-1 (programmed cell death protein 1), and PD-L1 (programmed cell death 1 ligand 1) in breast cancer patients, suitable for breast conservation and sentinel node biopsy and determine their associations with clinicopathological factors.Expression of the genes coding for PD-1 and PD-L1 was analyzed in formalin-fixed paraffin-embedded specimens using real-time PCR. mRNA expression levels were determined using beta actin (ACTB) as an endogenous control. There was a trend towards significance between higher PD-1 and PD-L1 levels in triple negative breast cancers (p=0.1). Higher PD-L1 expression was also found in aggressive breast cancer subtypes e.g. triple negative and HER2 (human epidermal growth factor receptor 2) -positive as compared with subtypes with better prognosis such as luminal A and luminal BHER2-negative (p=0.05). There was a trend towards significance in higher PD-1 levels in triple negative and HER-2 positive breast cancers (p=0.1). A statistically significant difference was found between PD-L1 expression and tumor grade (p=0.01). Elevated PD-L1 levels were noted in G3 tumors. Immunogenicity appears to be gaining importance in triple negative and HER2-positive molecular subtypes of breast cancer, and the results in this study provide a basis for further investigation into the role of immune checkpoints in breast cancer.

Variation in treatment and survival of older patients with non-metastatic breast cancer in five European countries: a population-based cohort study from the EURECCA Breast Cancer Group

BACKGROUND

Older patients are poorly represented in breast cancer research and guidelines do not provide evidence based recommendations for this specific group. We compared treatment strategies and survival outcomes between European countries and assessed whether variance in treatment patterns may be associated with variation in survival.

METHODS

Population-based study including patients aged ≥ 70 with non-metastatic BC from cancer registries from the Netherlands, Belgium, Ireland, England and Greater Poland. Proportions of local and systemic treatments, five-year relative survival and relative excess risks (RER) between countries were calculated.

RESULTS

In total, 236,015 patients were included. The proportion of stage I BC receiving endocrine therapy ranged from 19.6% (Netherlands) to 84.6% (Belgium). The proportion of stage III BC receiving no breast surgery varied between 22.0% (Belgium) and 50.8% (Ireland). For stage I BC, relative survival was lower in England compared with Belgium (RER 2.96, 95%CI 1.30-6.72, P < .001). For stage III BC, England, Ireland and Greater Poland showed significantly worse relative survival compared with Belgium.

CONCLUSIONS

There is substantial variation in treatment strategies and survival outcomes in elderly with BC in Europe. For early-stage BC, we observed large variation in endocrine therapy but no variation in relative survival, suggesting potential overtreatment. For advanced BC, we observed higher survival in countries with lower proportions of omission of surgery, suggesting potential undertreatment.

How Can We Improve Education of Breast Surgeons Across Europe?

The proposed global curriculum developed by the American Society of Surgical Oncology (SSO) and the European Society of Surgical Oncology (ESSO) and the textbook: provides a state-of- the- art of breast cancer surgery, complements the syllabus and curriculum of the Union Europeenne des Medecins Specialistes (UEMS) examination in breast surgery/ European Board of Surgery Qualification in Breast Surgery (EBSQinBS) administered by ESSO (1) Knowledge and understanding of the principles of breast cancer incidence, aetiology, risk factors, genetics, premalignant and high-risk lesions, pathology, prognostic and predictive factors, risk prediction models, screening, diagnosis and imaging, breast cancer, oncoplastic, reconstructive breast surgery, axillary surgery and future perspective for this, radiation therapy, neoadjuvant and adjuvant systemic treatment- endocrine-, immuno- and chemotherapy, side effects and toxicities of treatment, locoregional recurrence, follow-up, locally advanced breast cancer, metastatic breast cancer, breast cancer in young and elderly patients, survivor issues, lymphedema, palliative care, chroni pain, body image and sexuality, fertility issues, cognitive functions, etc.) (1) ESSO fellowships: for instance BSSO (Brazilian Society of Surgical Oncology)-ESSO fellowship, ESSO members are being offered the opportunity by the BSSO to apply for a visiting observership in Brazil; ESSO fellowship in Breast Surgery- the fellowship provides further specialised training in the multi-modality clinical care specific to the breast cancer patient and a deeper training in breast cancer research; training fellowships- to allow young surgeons to visit a specialist breast unit in Europe, to help them to expand their experience and learn new techniques; congress fellowships- for each ESSO congress the ESSO Scientific Committee awards a number of fellowship grantsto participants from low-income countries to attend the congress; EYSAC (ESSO Young Surgeons and Alumni Club) research fellowship; SSO/ ESSO fellowshipthrough its partnership with ESSO, SSO provides a grant to attend the SSO Annual Symposium; Reciprocal International Exchange Programmes with Japan, Latin America and North America (2). ESSO courses and masterclasses: expanded portfolio of courses, in- and outside Europe, basic and advanced, international faculty, multidisciplinary approach, learning methods: hands-on with human cadavers, workshops in small groups, live and case demonstrations, interactive sessions, 3D videos (for instance in 2017 ESSO course on ultrasound of breast in Barcelona, advanced course on oncoplastic surgery in Barcelona, advanced course on breast cancer surgery in Naples) (2). Trials: Interantional Nipple- Sparing Mastectomy Registry (INSPIRE), EURECCA (European Cancer Audit) project. The aim of INSPIRE is to provide pooled evidence derived from a prospective collaborative high-quality registry between international centers, oncological safety, patient- reported outcome measures, launched in March, 2016, European Breast Cancer Conference EBCC 10, Amsterdam (2).

EXAMINATION

European Board of Surgery Qualification in Breast Surgery (EBSQ in BS): phase 1-eligibility assessment (CV, logbook, references); phase 2- test; phase 3- oral examination with 2 clinical cases and 1 critical review of academic paper. The applicant must hold a current license to practice as a surgeon (general or plastic or gynaecologist), demonstrate work for one year in a breast surgery unit with at least 150 new primary breast cancer cases per year, attended at least one national/ international training course in breast surgery and has attended at least one well recognized international congress. The applicant should present a signed log book for breast surgery with application; published either one paper or book chapter on breast disease Conclusions 1. The need for certified breast units: Standardised techniques by specialist breast surgeons across Europe should be the aim. 2. No man'™s land. Across Europe oncoplastic reconstruction is performed by specialist breast, general or plastic surgeons, sometimes in collaboration with each other. There may be dispute as who should or should not be involved. This needs to be addressed. 3. Oncoplastic reconstruction technique expansion. Significant expansion in number, variety and complexity of available techniques is a fact. A good example would be a 6-fold increase together with a low rate of complications in some Eastern European countries over the last decade 4. CME. European breast surgeons want to improve their skills, as evidenced by fully or overbooked ESSO-endorsed breast surgery courses and other high quality workshops. Applications for the European Examination in Breast Surgery (EBSQBS) continue to increase.

Landscape of oncoplastic breast surgery across Poland

Oncoplastic and reconstructive techniques are essential tools in the armamentarium of contemporary breast surgeons. The aim of the study was to identify oncoplastic reconstructive patterns in breast cancer centers across Poland. A questionnaire of 18 questions was sent by email to the members of the Polish Society of Surgical Oncology and the Polish Society of Plastic, Reconstructive and Esthetic Surgery via their dedicated websites. The numbers of breast cancer patients operated on in each center ranged from 120 to 904 per year. Breast-conserving surgery (BCS) predominated in all but one center (range 50-70%). Immediate breast reconstructions (IBR) accounted for 6-42% of procedures, The most frequent type of IBR was either a two-stage expander followed by a permanent implant or one-stage implant- based with or without synthetic mesh. The most frequent type of delayed breast reconstruction (DBR) was a two-stage expander followed by implant-based reconstruction. None of the surveyed cancer centers performed free flap reconstruction. Deep inferior epigastric perforator (DIEP) flaps were performed in the plastic surgery department. Reconstructions based on pedicled flaps were performed in cancer centers. Acellular dermal matrices (ADM) and fat transfer were used in selected centers. In the clinical scenario of adjuvant radiotherapy, delayed breast reconstruction was favored. The full range of oncoplastic BCS was performed. Patient-reported outcome measures (PROM) and complications were assessed. Our findings can act as a platform for further improvement in skills, certification, data collection and audit, including patient reported expectation measures. There is also an urgent need to address pan-European inconsistencies in procedural reimbursement.

MGMT promoter methylation as a potential prognostic marker for acute leukemia

INTRODUCTION

It has been proved that genetic and epigenetic changes play a significant role in the development and progression of acute leukemia. The aim of our study was to evaluate the frequency and prognostic implications of genetic and epigenetic alterations in p15, MGMT, DNMT3A and TP53 genes in acute leukemias.

MATERIAL AND METHODS

We included in the study 59 patients with acute leukemia. Evaluation of TP53 and DNMT3A mutations was performed using sequencing analysis and PCR-RFLP, respectively. Methylation status of MGMT and p15 genes was evaluated using MSP and COBRA, respectively. For assessment of global DNA methylation ELISA-based kit was used.

RESULTS

We found that overall survival was higher for ALL patients. MGMT promoter methylation was significantly associated with patients age at the time of diagnosis (p = 0.03). TP53 and DNMT3A mutations were observed only in AML patients (16.67% and 8.8%, respectively). Patients with acute leukemia and p15 promoter methylation had significantly more frequently mutated TP53 gene (p = 0.04) and AML patients with p15 promoter methylation had significantly more frequently detected global hypomethylation of DNA (p = 0.009). In the group of ALL patients we noted an opposite trend: only patients negative for p15 promoter methylation were characterized by global DNA hypomethylation.

CONCLUSIONS

Our findings demonstrate that MGMT promoter methylation can have a considerable impact on the development of acute leukemia in older patients. DNMT3A and TP53 mutations may play a significant role in AML development. However, further studies conducted in a larger cohort of patients are needed to determine its clinical utility.

Association of microRNA-93, 190, 200b and receptor status in core biopsies from stage III breast cancer patients

Oncologists now favor more personalized treatment strategies in breast cancer patients. Gene expression analysis has been widely used, but less is known about epigenetic factors, for example, microRNAs (miRNAs). The aim of this study was to determine the relationship between selected miRNAs and receptor status in core biopsies sampled before preoperative chemotherapy in stage III locally advanced breast cancer (LABC) patients. In 37 LABC core biopsies, three miRNAs per sample were analyzed: hsa-miR-93-5p, hsa-miR-190a, and hsa-miR-200b-3p, and hsa-miR-103a-3p as an endogenous control (TaqMan(®) RT-PCR; Applied Biosystems). Receptor status was determined by a dedicated pathologist. The Mann-Whitney U, Shapiro-Wilk, and Levene's tests were used to compare related samples. Levels of miRNA-93 differed significantly in core biopsies of LABC patients with different expressions of ER (estrogen receptor) and PR (progesterone receptor). Higher levels of miRNA-93 were found in ER-negative (p=0.0027) and PR-negative patients (p=0.0185). Levels of miRNA-190 and 200b did not differ significantly in core biopsies of LABC patients who expressed ER and PR differently (p=0.7727, p=0.9434, p=0.6213, and p=0.1717). Levels of miRNA-93, 190, and 200b were not significantly different in core biopsies of LABC patients with different HER2 (human epidermal growth factor 2) expressions (p=0.8013, p=0.2609, and p=0.3222). The assessment of core biopsy miRNA profiles and receptor-based subtypes may identify new signaling pathways for improved breast cancer classification.

Association of microRNAs and pathologic response to preoperative chemotherapy in triple negative breast cancer: preliminary report

Triple negative breast cancer (TNBC) has caught the attention of oncologists worldwide because of poor prognosis and paucity of targeted therapies. Gene pathways have been widely studied, but less is known about epigenetic factors such as microRNAs (miRNAs) and their role in tailoring an individual systemic and surgical approach for breast cancer patients. The aim of the study was to examine selected miRNAs in TNBC core biopsies sampled before preoperative chemotherapy and the subsequent pathologic response in mastectomy or breast conservation specimens. Prior to treatment, core needle biopsies were collected from 11 female patients with inoperable locally advanced TNBC or large resectable tumors suitable for down-staging. In all 11 TNBC core biopsies we analyzed 19 miRNAs per sample: 512, 190, 200, 346, 148, 449, 203, 577, 93, 126, 423, 129, 193, 182, 136, 135, 191, 122 and 222 (miRCURY LNA™ Universal RT microRNA polymerase chain reaction Custom Pick & Mixpanels). The Wilcoxon signed-rank test was used to compare related samples. Ingenuity pathway analysis was used to evaluate potential functional significance of differentially expressed miRNAs. Statistical analysis showed that 3 of 19 miRNAs differed in relation to pathologic response i.e. good versus poor. These differences failed to reach statistical significance, although a trend was observed (p = 0.06). Among these miRNAs, we identified—miR-200b-3p, miR-190a and miR-512-5p. In summary, our results indicate that higher miR-200b-3p, higher miR-190a and lower miR-512-5p expression levels in core biopsies sampled from TNBC patients may be associated with better pathologic response to chemotherapy and the increased feasibility of breast conserving surgery in these patients. Although these results were from a small cohort, they provide an important basis for larger, prospective, multicenter studies to investigate the potential role of miRNAs in neoadjuvant setting.

Apoptosis-, proliferation, immune function-, and drug resistance- related genes in ER positive, HER2 positive and triple negative breast cancer

The aim of our study was to examine an association between gene expression assessed using a 23-gene microarray and receptor status of breast cancer samples categorized as ER positive, HER2 positive and triple negative subtypes. The ER positive cohort was subsequently divided into Luminal A, Luminal B HER2 negative and Luminal B HER2 positive subtypes. Core- needle biopsies were collected from 78 female patients with inoperable locally advanced breast cancer or resectable tumors suitable for downstaging, before any treatment. Expressions of 23 genes were determined by means of TagMan Low Density Arrays. Analysis of variance was used to select genes with discriminatory potential between receptor subtypes. We introduced a correction for false discovery rates (presented as q values) due to testing multiple hypothesis. Pairwise post-hoc comparisons of receptor subtypes were performed using Tukey 's HSD test. Five genes out of a 23-gene microarray differed significantly in relation to breast cancer receptor-based subtypes. Among these five genes, we identified: BCL2 (p=0.0002, q=0.0009), MKI67 (p=0.0037, q=0.0064), IGF1R (p=0.0040, q=0.0064), FOXC1 (p=0.0113, q=0.0135) and IRF1 (p=0.0435, q=0.0416) as ones showing ER positive, HER2 positive and triple negative -subtype specific expression profiles. When incorporating Luminal A, Luminal B HER2 negative, Luminal B HER2 positive subtypes into analysis, four genes: BCL2 (p=0.0006, q=0.0034), MKI67 (p=0.0078, q=0.0198), FOXC1 (p=0.0102, q=0.0198) and IGF1R (p=0.0174, q=0.0254) were selected. Elevated levels of IGF1R and BCL2 were significantly linked with Luminal A subtype. Triple negative breast cancer subtype was associated with higher expression of IRF1, FOXC1 and MKI67. In HER2 positive cohort lower expression of all five analyzed genes was noted.

Gene expression and pathologic response to neoadjuvant chemotherapy in breast cancer

Pathologic complete response after neoadjuvant systemic treatment appears to be a valid surrogate for better overall survival in breast cancer patients. Currently, together with standard clinicopathologic assessment, novel molecular biomarkers are being exhaustively tested in order to look into the heterogeneity of breast cancer. The aim of our study was to examine an association between 23-gene real-time-PCR expression assay including ABCB1, ABCC1, BAX, BBC3, BCL2, CASP3, CYP2D6, ERCC1, FOXC1, GAPDH, IGF1R, IRF1, MAP2, MAPK 8, MAPK9, MKI67, MMP9, NCOA3, PARP1, PIK3CA, TGFB3, TOP2A, and YWHAZ receptor status of breast cancer core biopsies sampled before neoadjuvant chemotherapy (anthracycline and taxanes) and pathologic response. Core-needle biopsies were collected from 42 female patients with inoperable locally advanced breast cancer or resectable tumors suitable for downstaging, before any treatment. Expressions of 23 genes were determined by means of TagMan low density arrays. Analysis of variance was used to select genes with discriminatory potential between receptor subtypes. We introduced a correction for false discovery rates (presented as q values) due to multiple hypothesis testing. Statistical analysis showed that seven genes out of a 23-gene real-time-PCR expression assay differed significantly in relation to pathologic response regardless of breast cancer subtypes. Among these genes, we identified: BAX (p = 0.0146), CYP2D6 (p = 0.0063), ERCC1 (p = 0.0231), FOXC1 (p = 0.0048), IRF1 (p = 0.0022), MAP2 (p = 0.0011), and MKI67 (p = 0.0332). The assessment of core biopsy gene profiles and receptor-based subtypes, before neoadjuvant therapy seems to predict response or resistance and to define new signaling pathways to provide more powerful classifiers in breast cancer, hence the need for further research.

Polymorphisms of the BRCA2 and RAD51 genes in breast cancer

We performed a case-control study (150 cases and 150 controls) to test the association between three polymorphisms in BRCA2 and RAD51 genes and breast cancer risk. Genotypes were determined in DNA from blood cells by PCR-RFLP. Cancer occurrence was strongly associated with the BRCA2 Met/1915Thr homozygous polymorphic variants, whereas heterozygous variant was associated with significant reduction in breast cancer risk. Gene-gene interaction between the BRCA2-Met1915Thr Thr/Thr and BRCA2-Met784Val Met/Met homozygous variants increased the risk. Therefore, the Met1915Thr polymorphism in the BRCA2 gene may be considered as an independent marker of breast cancer.

The DNA-damaging potential of tamoxifen in breast cancer and normal cells

Tamoxifen (TAM) is a non-steroidal anti-estrogen used widely in the treatment and chemoprevention of breast cancer. TAM treatment can lead to DNA damage, but the mechanism of this process is not fully understood and the experimental data are often inconclusive. We compared the DNA-damaging potential of TAM in normal human peripheral blood lymphocytes and MCF-7 breast cancer cells by using the comet assay. In order to assess whether oxidative DNA damage may contribute to TAM-induced lesions, we employed two DNA repair enzymes: endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg). The kinetics of repair of DNA damage was also measured. In order to evaluate the involvement of free radicals in the genotoxicity of TAM we pre-treated the cells with nitrone spin traps: DMPO and POBN. The use of common antioxidants: vitamin C, amifostine and genistein, helped to assess the contribution of free radicals. TAM damaged DNA in both normal and cancer cells, inducing mainly DNA strand breaks but not alkali-labile sites. The drug at 5 and 10 microM induced DNA double strand breaks (DSBs) in lymphocytes and at 10 microM in MCF-7 cells. We observed complete repair of DSBs in cancer cells by contrast with incomplete repair of these lesions in lymphocytes. In both types of cells TAM induced oxidized purines and pyrimidines. Incubation of the cells with nitrone spin traps and antioxidants decreased, with exception of amifostine in MCF-7 cells, the extents of DNA damage in both kinds of cells, but the results were more distinct in cancer cells. Our results indicate that TAM can be genotoxic for normal and cancer cells by free radicals generation. It seems to have a higher genotoxic potential for normal cells, which can be the result of incomplete repair of DNA DSBs. Free radicals scavengers can modulate TAM-induced DNA damage interfering with its antitumour activity in cancer cells.

Polymorphisms of the DNA mismatch repair gene HMSH2 in breast cancer occurence and progression

The response of the cell to DNA damage and its ability to maintain genomic stability by DNA repair are crucial in preventing cancer initiation and progression. Therefore, polymorphism of DNA repair genes may affect the process of carcinogenesis. The importance of genetic variability of the components of mismatch repair (MMR) genes is well documented in colorectal cancer, but little is known about its role in breast cancer. hMSH2 is one of the crucial proteins of MMR. We performed a case-control study to test the association between two polymorphisms in the hMSH2 gene: an A --> G transition at 127 position producing an Asn --> Ser substitution at codon 127 (the Asn127Ser polymorphism) and a G --> A transition at 1032 position resulting in a Gly --> Asp change at codon 322 (the Gly322Asp polymorphism) and breast cancer risk and cancer progression. Genotypes were determined in DNA from peripheral blood lymphocytes of 150 breast cancer patients and 150 age-matched women (controls) by restriction fragment length polymorphism and allele-specific PCR. We did not observe any correlation between studied polymorphisms and breast cancer progression evaluated by node-metastasis, tumor size and Bloom-Richardson grading. A strong association between breast cancer occurrence and the Gly/Gly phenotype of the Gly322Asp polymorphism (odds ratio 8.39; 95% confidence interval 1.44-48.8) was found. Therefore, MMR may play a role in the breast carcinogenesis and the Gly322Asp polymorphism of the hMSH2 gene may be considered as a potential marker in breast cancer.

Polymorphisms of the promoter regions of matrix metalloproteinases genes MMP-1 and MMP-9 in breast cancer

PURPOSE

Matrix metalloproteinases play a crucial role in the cancer invasion and metastasis, angiogenesis and tumorigenicity. A single guanine insertion--the 1G/2G polymorphism in the promoter of the matrix metalloproteinase 1 (MMP-1) gene creates a binding site for the transcription factor AP-1 and thus may affect the transcription level of MMP-1. The C-->T substitution at the polymorphic site of the MMP-9 gene promoter results in a higher transcription activity of the T-allelic promoter trough the loss of binding site for a repressor protein. The aim of this work was to investigate the influence of 1G/2G and C-->T polymorphisms on the MMP-1 and MMP-9 level and therefore on the occurrence and progression of breast cancer.

EXPERIMENTAL DESIGN

We investigated the distribution of genotypes and frequency of alleles of the 1G/2G and C-->T polymorphisms for 270 patients with breast cancer and 300 healthy women served as control. The genotypes were determined by RFLP-PCR. Additionally, we estimated the level of MMP-1 and MMP-9 antigens in tumor samples and normal breast tissue using ELISA.

RESULTS

The levels of MMP-1 in tumor samples of node positive patients ware significantly higher than in samples of node negative patients (p<0.05). Increased level of MMP-9 correlates with Bloom-Richardson grading III (p<0.05), increased tumor size (p<0.05) and absence of estrogen and progesterone receptors (p<0.01). Additionally, both MMP-1 and MMP-9 levels were higher in tumor than in the normal breast tissue. We showed the higher risk of metastasis development in lymph node for the 2G/2G genotype (OR=2.14; CI 95% 1.24;3.69) and the 2G allele carriers (OR=1.68; CI 95% 1.19;2.39). We found correlation between the T allele (OR=2.61; CI 95% 1.33;4.87), 2G (OR=2.58; CI 95% 1.35;4.91) and malignance.

CONCLUSION

The results suggest that MMP-1 is responsible for the local invasion and MMP-9 is associated with the malignance and the growth of the tumor. We suggest that the 2G allele of the 1G/2G MMP-1 gene polymorphism may be associated with the lymph node metastasis in patients with breast cancer and therefore it can be considered as a progression marker in this disease.

Basal, oxidative and alkylative DNA damage, DNA repair efficacy and mutagen sensitivity in breast cancer

Impaired DNA repair may fuel up malignant transformation of breast cells due to the accumulation of spontaneous mutations in target genes and increasing susceptibility to exogenous carcinogens. Moreover, the effectiveness of DNA repair may contribute to failure of chemotherapy and resistance of breast cancer cells to drugs and radiation. The breast cancer susceptibility genes BRCA1 and BRCA2 are involved in DNA repair. To evaluate further the role of DNA repair in breast cancer we determined: (1) the kinetics of removal of DNA damage induced by hydrogen peroxide and the anticancer drug doxorubicin, and (2) the level of basal, oxidative and alkylative DNA damage before and during/after chemotherapy in the peripheral blood lymphocytes of breast cancer patients and healthy individuals. The level of DNA damage and the kinetics of DNA repair were evaluated by alkaline single cell gel electrophoresis (comet assay). Oxidative and alkylative DNA damage were assayed with the use of DNA repair enzymes endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg), recognizing oxidized DNA bases and 3-methyladenine-DNA glycosylase II (AlkA) recognizing alkylated bases. We observed slower kinetics of DNA repair after treatment with hydrogen peroxide and doxorubicin in lymphocytes of breast cancer patients compared to control individuals. The level of basal, oxidative and alkylative DNA damage was higher in breast cancer patients than in the control and the difference was more pronounced when patients after chemotherapy were engaged, but usually the level of DNA damage in these patients was too high to be measured with our system. Our results indicate that peripheral blood lymphocytes of breast cancer patients have more damaged DNA and display decreased DNA repair efficacy. Therefore, these features can be considered as risk markers for breast cancer, but the question whether they are the cause or a consequence of the illness remains open. Nevertheless, our results suggest that research on the mutagen sensitivity and efficacy of DNA repair could impact the development of new diagnostic and screening strategies as well as indicate new targets to prevent and cure cancer. Moreover, the comet assay may be applied to evaluate the suitability of a particular mode of chemotherapy to a particular cancer patient.

An association between the matrix metalloproteinase 1 promoter gene polymorphism and lymphnode metastasis in breast cancer

A single guanine insertion (1G/2G polymorphism) in the promoter of the matrix metalloproteinase (MMP-1) gene creates a binding site for the transcription factor and may affect the level of transcription of MMP-1. An elevated level of MMP-1 in cancer cells may facilitate their invasion and contribute to metastasis. To evaluate the contribution of 1G/2G polymorphism in the development and/or progression of breast cancer we genotyped 135 subjects with breast cancer. The 1G/2G polymorphism was determined by the method based on restriction endonuclease digestion. We found that the frequency of the 2G allele was higher in lymphnode-metastasis patients than in the group without metastasis (p < 0.001). We did not find differences between distribution of the genotypes and frequencies of alleles in cancer patients and in healthy subjects served as control. Our results suggest that allele 2G may be associated with lymphnode metastasis in patients with breast cancer and therefore it can be considered as a prognostic marker in this disease.