Bernard Lespérance

Evaluation of BRCA1 and BRCA2 mutation prevalence, risk prediction models and a multistep testing approach in French-Canadian families with high risk of breast and ovarian cancer

Background and objective: In clinical settings with fixed resources allocated to predictive genetic testing for high-risk cancer predisposition genes, optimal strategies for mutation screening programmes are critically important. These depend on the mutation spectrum found in the population under consideration and the frequency of mutations detected as a function of the personal and family history of cancer, which are both affected by the presence of founder mutations and demographic characteristics of the underlying population. The results of multistep genetic testing for mutations in BRCA1 or BRCA2 in a large series of families with breast cancer in the French-Canadian population of Quebec, Canada are reported. Methods: A total of 256 high-risk families were ascertained from regional familial cancer clinics throughout the province of Quebec. Initially, families were tested for a panel of specific mutations known to occur in this population. Families in which no mutation was identified were then comprehensively tested. Three algorithms to predict the presence of mutations were evaluated, including the prevalence tables provided by Myriad Genetics Laboratories, the Manchester Scoring System and a logistic regression approach based on the data from this study. Results: 8 of the 15 distinct mutations found in 62 BRCA1/BRCA2-positive families had never been previously reported in this population, whereas 82% carried 1 of the 4 mutations currently observed in ⩾2 families. In the subset of 191 families in which at least 1 affected individual was tested, 29% carried a mutation. Of these 27 BRCA1-positive and 29 BRCA2-positive families, 48 (86%) were found to harbour a mutation detected by the initial test. Among the remaining 143 inconclusive families, all 8 families found to have a mutation after complete sequencing had Manchester Scores ⩾18. The logistic regression and Manchester Scores provided equal predictive power, and both were significantly better than the Myriad Genetics Laboratories prevalence tables (p<0.001). A threshold of Manchester Score ⩾18 provided an overall sensitivity of 86% and a specificity of 82%, with a positive predictive value of 66% in this population. Conclusion: In this population, a testing strategy with an initial test using a panel of reported recurrent mutations, followed by full sequencing in families with Manchester Scores ⩾18, represents an efficient test in terms of overall cost and sensitivity.

Mutation analysis and characterization of ATR sequence variants in breast cancer cases from high-risk French Canadian breast/ovarian cancer families

BackgroundAtaxia telangiectasia-mutated and Rad3-related (ATR) is a member of the PIK-related family which plays, along with ATM, a central role in cell-cycle regulation. ATR has been shown to phosphorylate several tumor suppressors like BRCA1, CHEK1 and TP53. ATR appears as a good candidate breast cancer susceptibility gene and the current study was designed to screen for ATR germline mutations potentially involved in breast cancer predisposition.MethodsATR direct sequencing was performed using a fluorescent method while widely available programs were used for linkage disequilibrium (LD), haplotype analyses, and tagging SNP (tSNP) identification. Expression analyses were carried out using real-time PCR.ResultsThe complete sequence of all exons and flanking intronic sequences were analyzed in DNA samples from 54 individuals affected with breast cancer from non-BRCA1/2 high-risk French Canadian breast/ovarian families. Although no germline mutation has been identified in the coding region, we identified 41 sequence variants, including 16 coding variants, 3 of which are not reported in public databases. SNP haplotypes were established and tSNPs were identified in 73 healthy unrelated French Canadians, providing a valuable tool for further association studies involving the ATR gene, using large cohorts. Our analyses led to the identification of two novel alternative splice transcripts. In contrast to the transcript generated by an alternative splicing site in the intron 41, the one resulting from a deletion of 121 nucleotides in exon 33 is widely expressed, at significant but relatively low levels, in both normal and tumoral cells including normal breast and ovarian tissue.ConclusionAlthough no deleterious mutations were identified in the ATR gene, the current study provides an haplotype analysis of the ATR gene polymorphisms, which allowed the identification of a set of SNPs that could be used as tSNPs for large-scale association studies. In addition, our study led to the characterization of a novel Δ33 splice form, which could generate a putative truncated protein lacking several functional domains. Additional studies in large cohorts and other populations will be needed to further evaluate if common and/or rare ATR sequence variants can be associated with a modest or intermediate breast cancer risk.

Activity and Safety of the Antiestrogen EM-800, the Orally Active Precursor of Acolbifene, in Tamoxifen-Resistant Breast Cancer

PURPOSE To determine the efficacy and safety of EM-800 (SCH-57050), the precursor of acolbifene, a new, highly potent, orally active, pure antiestrogen in the mammary gland and endometrium, for the treatment of tamoxifen-resistant breast cancer. PATIENTS AND METHODS Forty-three post menopausal/ovariectomized women with breast cancer who had received tamoxifen, either for metastatic disease or as adjuvant to surgery for > or = 1 year, and had relapsed were treated in a prospective, multicenter, phase II study with EM-800 (20 mg/d [n = 21] or 40 mg/d [n = 22] orally). Results Thirty-seven patients had estrogen receptor (ER)-positive tumors (>10 fmol/mg; mean, 146 fmol/mg cytosolic protein), three patients had ER-negative/progesterone receptor-positive tumors, and three patients had undetermined ER status. The objective response rate to EM-800 was 12%, with one complete response and four partial responses. Ten patients (23%) had stable disease for > or = 3 months, and 7 patients (16%) had stable disease for > or = 6 months. With a median follow-up of 29 months, median duration of response was 8 months (range, 7 to 71+ months). Treatment with EM-800 was well tolerated. No significant adverse events related to the study drug were observed clinically or biochemically. CONCLUSION EM-800 produced responses in a significant proportion of patients with tamoxifen-resistant breast cancer, thus showing that this highly potent, selective estrogen receptor modulator, which lacks estrogenic activity in the mammary gland and endometrium, has incomplete cross-resistance with tamoxifen, thus suggesting additional benefits in the treatment of breast cancer.

Germline mutations in the breast cancer susceptibility gene PTEN are rare in high-risk non-BRCA1/2 French Canadian breast cancer families

Cowden syndrome is a disease associated with an increase in breast cancer susceptibility. Alleles in PTEN and other breast cancer susceptibility genes would be responsible for ∼25% of the familial component of breast cancer risk, BRCA1 and BRCA2 being the two major genes responsible for this inherited risk. In order to evaluate the proportion of high-risk French Canadian non-BRCA1/BRCA2 breast/ovarian cancer families potentially harboring a PTEN germline mutation, the whole coding and flanking intronic sequences were analyzed in a series of 98 breast cancer cases. Although no germline mutation has been identified in the coding region, our study led to the identification of four intronic variants. Further investigations were performed to analyze the effect of these variants, alone and/or in combination, on splicing and PTEN protein levels. Despite suggestive evidence emerging from in silico analyses, the presence of these intronic variants do not seem to alter RNA splicing or PTEN protein levels. In addition, as loss of PTEN or part of it has been reported, Western blot analysis has also been performed. No major deletion could be identified in our cohort. Therefore, assuming a Poisson distribution for the frequency of deleterious mutation in our cohort, if the frequency of such deleterious mutation was 2%, we would have had a 90% or greater chance of observing at least one such mutation. These results suggest that PTEN germline mutations are rare and are unlikely to account for a significant proportion of familial breast cancer cases in the French Canadian population.

Next-generation biobanking of metastases to enable multidimensional molecular profiling in personalized medicine

Great advances in analytical technology coupled with accelerated new drug development and growing understanding of biological challenges, such as tumor heterogeneity, have required a change in the focus for biobanking. Most current banks contain samples of primary tumors, but linking molecular signatures to therapeutic questions requires serial biopsies in the setting of metastatic disease, next-generation of biobanking. Furthermore, an integration of multidimensional analysis of various molecular components, that is, RNA, DNA, methylome, microRNAome and post-translational modifications of the proteome, is necessary for a comprehensive view of a tumor’s biology. While data using such biopsies are now regularly presented, the preanalytical variables in tissue procurement and processing in multicenter studies are seldom detailed and therefore are difficult to duplicate or standardize across sites and across studies. In the context of a biopsy-driven clinical trial, we generated a detailed protocol that includes morphological evaluation and isolation of high-quality nucleic acids from small needle core biopsies obtained from liver metastases. The protocol supports stable shipping of samples to a central laboratory, where biopsies are subsequently embedded in support media. Designated pathologists must evaluate all biopsies for tumor content and macrodissection can be performed if necessary to meet our criteria of >60% neoplastic cells and <20% necrosis for genomic isolation. We validated our protocol in 40 patients who participated in a biopsy-driven study of therapeutic resistance in metastatic colorectal cancer. To ensure that our protocol was compatible with multiplex discovery platforms and that no component of the processing interfered with downstream enzymatic reactions, we performed array comparative genomic hybridization, methylation profiling, microRNA profiling, splicing variant analysis and gene expression profiling using genomic material isolated from liver biopsy cores. Our standard operating procedures for next-generation biobanking can be applied widely in multiple settings, including multicentered and international biopsy-driven trials.

Genetic variants and haplotype analyses of the ZBRK1/ZNF350 gene in high-risk non BRCA1/2 French Canadian breast and ovarian cancer families.

Our current understanding of breast cancer susceptibility involves mutations in the 2 major genes BRCA1 and BRCA2, found in about 25% of high‐risk families, as well as few other low penetrance genes such as ATM and CHEK2. Approximately two‐thirds of the multiple cases families remain to be explained by mutations in still unknown genes. In a candidate gene approach to identify new genes potentially involved in breast cancer susceptibility, we analyzed genomic variants in the ZBRK1 gene, a co‐repressor implicated in BRCA1‐mediated repression of GADD45. Direct sequencing of ZBRK1 entire coding region in affected breast cancer individuals from 97 high‐risk French Canadian breast/ovarian cancer families and 94 healthy controls led to the identification of 18 genomic variants. Haplotype analyses, using PHASE, COCAPHASE and HaploStats programs, put in evidence 3 specific haplotypes which could potentially modulate breast cancer risk, and among which 2 that are associated with a potential protective effect (p = 0.01135 and p = 0.00268), while another haplotype is over‐represented in the case group (p = 0.00143). Further analyses of these haplotypes indicated that a strong component of the observed difference between both groups emerge from the first 5 variants (out of 12 used for haplotype determination). The present study also permitted to determine a set of tagging SNPs that could be useful for subsequent analyses in large scale association studies. Additional studies in large cohorts and other populations will however be needed to further evaluate if common and/or rare ZBRK1 sequence variants and haplotypes could be associated with a modest/intermediate breast cancer risk.

Adjuvant treatment for endometrial cancer: Literature review and recommendations by the Comité de l'évolution des pratiques en oncologie (CEPO)

OBJECTIVE Despite the very good prognosis of endometrial cancer, a number of patients with localized disease relapse following surgery. Therefore, various adjuvant therapeutic approaches have been studied. The objective of this review is to evaluate the efficacy and safety of neoadjuvant and adjuvant therapies in patients with resectable endometrial cancer and to develop evidence-based recommendations. METHODS A review of the scientific literature published between January 1990 and June 2012 was performed. The search was limited to published phase III clinical trials and meta-analyses evaluating the efficacy of neoadjuvant or adjuvant therapies in patients with endometrial carcinoma or carcinosarcoma. A total of 23 studies and five meta-analyses were identified. RESULTS The selected literature showed that in patients with a low risk of recurrence, post-surgical observation is safe and recommended in most cases. There are several therapeutic modalities available for treatment of endometrial cancers with higher risk of recurrence, including vaginal brachytherapy, external beam radiotherapy, chemotherapy, or a combination of these. CONCLUSIONS Considering the evidence available to date, the CEPO recommends the following: (1)post-surgical observation for most patients with a low recurrence risk; (2)adjuvant vaginal brachytherapy for patients with an intermediate recurrence risk; (3)adjuvant pelvic radiotherapy with or without vaginal brachytherapy for patients with a high recurrence risk; addition of adjuvant chemotherapy may be considered as an option for selected patients (excellent functional status, no significant co-morbidities, poor prognostic factors); (4)adjuvant chemotherapy and pelvic radiotherapy with or without brachytherapy and para-aortic irradiation for patients with advanced disease;

A Phase I Trial of Standard and Cyclophosphamide Dose-Escalated CHOP with Granulocyte Colony Stimulating Factor in Elderly Patients with Non-Hodgkin's Lymphoma

The purpose of this study was to assess the safety and feasibility of using standard and escalated doses of cyclophosphamide with doxorubicin, vincristine and prednisone (CHOP) plus granulocyte colony stimulating factor (G-CSF) to treat elderly patients who have advanced stage intermediate grade lymphoma. Consenting patients age > or = 65 years who had an acceptable performance status and adequate cardiac, renal and liver function were eligible for this Phase I study. G-CSF, 5 ug per kg, was given daily with each cycle from day 2 until neutrophil recovery of > or = 10 x 10(9)/L. Ten patients received standard CHOP; sequential cohorts of 5 patients were then to be given CHOP with cyclophosphamide doses of 900, 1050, 1200, and 1350 mg/m2. If 2 patients had dose limiting toxicity, cohorts were expanded to 10 patients; if 3 patients within a cohort had dose limiting toxicity, the previous dose level was considered the maximum tolerated dose of cyclophosphamide. Secondary outcomes were average relative received dose intensity, response, progression-free and overall survival, toxicity, hospitalizations and transfusions. Eight patients (80%) completed 6 cycles of standard CHOP plus G-CSF. Therapy was stopped prematurely in 2 patients due to pneumonia (1) and disease progression (1). Six of 11 patients (55%) given CHOP with cyclophosphamide 900 mg/m2 (CHOP-900) completed treatment. Therapy was stopped in 5 patients due to a toxic death from infection (1), cumulative fatigue (3), and pneumonitis (1). Further dose escalations were not attempted due to the inability to complete 6 treatment cycles in 45% of CHOP-900 cases. The received dose intensities of cyclophosphamide relative to standard CHOP measured over the actual time on therapy were 96% with standard CHOP and 115% with CHOP-900. At 3 years, progression free survival is 40% with standard CHOP and 82% with CHOP-900; overall survivals are 40% and 91% respectively. Neutropenia of < 1.0 x 10(9)/L occurred in 47% of treatment cycles with standard CHOP and in 77% with CHOP-900. In both groups, the mean duration of neutropenia was < 2 days. From these studies we conclude that, standard CHOP with G-CSF can be safely given to elderly patients. Escalating the dose of cyclophos

Partnering in oncogenetic research--the INHERIT BRCAs experience: opportunities and challenges.

Today it is common to conduct research in collaboration with colleagues from different disciplines and institutions. The INterdisciplinary HEalth Research International Team on BReast CAncer susceptibility (INHERIT BRCAs), involves Canadian and international experts from diverse fields working with health service providers, patients and collaborators from the World Health Organization and other European networks. Evidence-based information and knowledge transfer drive our efforts to advance genomic research to understand the genetic basis of cancer susceptibility and treatment response. Several goals reveal the interdisciplinary team approach: (a) to estimate the prevalence and penetrance of BRCA1 and BRCA2 mutations and their deleterious impact upon different populations; (b) to pinpoint novel breast cancer susceptibility loci; (c) to assess the efficacy of clinical interventions; (d) to address changes in quality of life and health-related behaviour from the decision to undergo genetics testing and during follow-up; (e) to evaluate legal, social and ethical implications; and, finally; (f) to promote professional and public education by facilitating the transfer of research findings to clinical practice and informing policy makers. The lessons learned by the INHERIT research team and future challenges are presented.

Inhibition of Streptokinase-Induced, Antibody-Mediated Platelet Aggregation with Tirofiban After Exposure to Streptokinase or Streptococcal Infection

Study Objective. To evaluate the effect of tirofiban (a glycoprotein IIb‐IIIa inhibitor) in preventing streptokinase‐induced, antibody‐mediated platelet aggregation after administration of streptokinase or development of a streptococcal infection.