Abstract P5-09-12: Germline mutation in TP53 gene in a cohort of 2,561 Chinese high-risk breast cancer patients using multigene panel testing

Background: Li-Fraumeni syndrome (LFS) is a rare autosomal genetic disorder with germline TP53 mutations. Patients with TP53 mutations have a higher risk of developing breast cancer than those harboring BRCA mutations. Although limited studies have shown that TP53 mutation carriers are less responsive to low dose radiation and more susceptible to induce new malignancies from radiotherapy. Moreover screening strategies allows early detection of a spectrum of cancers related to TP53 mutations. From work of BRCA mutations where over 40% novel mutations were detected in Chinese cohort, it is important to evaluate the frequency of TP53 mutation in Chinese to better understand the spectrum to guide appropriate clinical management of these high risk individuals.

Methods: TP53 gene mutation screening was performed on 2,561 high-risk breast cancer patients using multigene panel testing. The patients were accrued by Hong Kong Hereditary and High Risk Breast Cancer Program from March 2007 to May 2018. All detected pathogenic mutations were further validated by bi-directional DNA sequencing and analyzed by our in-house developed bioinformatics pipeline.

Results: Sixteen distinct pathogenic or likely pathogenic variants were identified, and 3 of them were de novo TP53 mutations (18.75%). The mean age of patients who harbored TP53 mutation was 30.44 years (range 18-44), and 50% of the tumors were bilateral breast cancer. Of sixteen different pathogenic mutations, majority of them were missense mutation (87.5%), and 2 were nonsense mutation (12.5%). Four of the sixteen TP53 mutation carriers had family history of breast cancer, while others had a family history of lung cancer (43.75%).

Conclusion: This study revealed that seven patients were found to habor TP53 mutation even when they did not meet the criteria of LFS of LFS-like phenotype, implicated the importance of using multigene panel test for probands and their relatives to offer a comprehensive surveillance programe for TP53 carriers.

Citation Format: Kwong A, Shin V, Au CH, Ho C, Slavin T, Weitzel J, Chan TL, Ma E. Germline mutation in TP53 gene in a cohort of 2,561 Chinese high-risk breast cancer patients using multigene panel testing [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-12.

Abstract P2-09-12: Prevalence of Hispanic BRCA1 and BRCA2 mutations among HBOC patients from Southern Brazil reveal differences among Latin American populations

Background.Breast cancer (BC) is the most common malignancy in women around the world, and 5% of BC cases and 15% of ovarian cancer (OC) cases can be attributed to BRCA1 and BRCA2 germline mutations, configuring Hereditary Breast and Ovarian Cancer Syndorme (HBOC). Considering that the genetic similarities between Latin American populations are largely unknown, we aimed to address if a panel of Hispanic BRCA mutations could be useful for a Brazilian population. Methods.Unrelated patients fulfilling NCCN criteria for HBOC syndrome were recruited. ASCO, Myriad and Penn II clinical testing criteria were analyzed for all patients. Blood-derived DNA samples were screened for 114 BRCA mutations, in a panel estimated to account for up to 90% of all BRCA Hispanic mutations (HISPANEL), using the Sequenom MassArray platform. Results. Among a total of 233 unrelated patients included (225 women and 8 men), 85% were BC patients and 14 patients were cancer unaffected. The mean age at diagnosis was 43 years for BC affected individuals and 45 years for patients with OC. Fifty-three patients fulfilled ASCO criteria, and 182 had Penn II≥10%, while only 64 had a Myriad score ≥10%. BRCA mutations were detected in 9 of 233 patients (prevalence of 3.86%). Among BC and/or OC affected individuals, this prevalence was 4.22%. Features of mutation carriers are depicted in table 1.

Table 1. BRCA mutations identified in Brazilian HBOC patients Mutation Gender Tumor type and age at diagnosis Family history of cancer BRCA1 c.3331_3334delCAAGFemaleOvCa, 47; BrCa, 50Daughter BrCa≤20;Brother PrCa 54;Cousin BrCa≥ 50 BRCA1 c.5266dupCFemaleBilateral BrCa, 35 and 45Mother OvCa 58;Aunt OvCa 49;Cousin BrCa 49;Great-grandmother BrCa 90 BRCA1 c.5266dupCFemaleBrCa, 36Aunt BrCa 62;Cousin BrCa 45;Cousin BrCa 44;Cousin Bilateral BrCa 45;Cousin BrCa 44;Cousin OvCa 52 BRCA1 c.5266dupCFemaleOvCa, 52Mother OvCa 77;Sister BrCa 44;Aunt OvCa 66 BRCA1 c.5266dupCFemaleBilateral BrCa, 23 and 44Mother BrCa 45;Aunt Bilateral BrCa 48;Cousin BrCa 30;Aunt Bilateral BrCa 58;Grandmother BrCa BRCA1 c.5266dupCFemaleBilateral BrCa, 26Sister BrCa 50;Niece BrCa 28;Niece BrCa 30 BRCA1 c.5266dupCMaleBrCa, 64Daughter BrCa 34;Sister BrCa≤ 50;Sister BrCa 32 BRCA2 c.2806_2809delAAACFemaleBrCa, 49Sister BrCa 32;Sister BrCa 44;Aunt Bilateral BrCa 40 and 55 BRCA2 c.2806_2809delAAACFemaleBilateral triple negative BrCa, 42 and 55NoneBrCa=breast cancer; OvCa=ovarian cancer.

Conclusions. The HISPANEL detects 59 BRCA1 and 55 BRCA2 mutations, including some mutations previously reported in Brazilian individuals. Most mutation carriers had the BRCA1 c.5266dupC (5382insC) mutation, a common founder mutation in several populations. Our results are largely different from other Latin American published data. Although low BRCA prevalence mutational rates were also seen in Peru and Mendellín (Colombia), in Mexico and Bogota (Colombia) a prevalence of 27% and 15%, respectively, was found in studies using HISPANEL and all studies included patients unselected for family history. Our findings reinforce that different Latin-American populations have different BRCA mutational profiles.

Citation Format: Alemar B, Herzog J, Ashton-Prolla P, Weitzel J. Prevalence of Hispanic BRCA1 and BRCA2 mutations among HBOC patients from Southern Brazil reveal differences among Latin American populations. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-09-12.

Abstract P2-16-05: Efficacy of ABT-888 (veliparib) in patients with BRCA-associated breast cancer

Background: The potential for exploiting BRCA deficiencies with DNA repair inhibitors has both pre-clinical and clinical support. ABT-888 (veliparib), a DNA repair inhibitor initially thought to target Poly(ADP-Ribose) Polymerases (PARP), has demonstrated in vitro inhibition of BRCA1 and BRCA2 deficient mouse embryonic stell cells, with a larger effect on BRCA1 cells. We report on the pre-planned interim analysis of the efficacy of single agent veliparib in patients with either BRCA1 or BRCA2-associated stage IV breast cancer. Methods: BRCA 1 or 2 carrier patients with stage IV breast cancer, with measurable disease, without prior exposure to a PARP inhibitor or a platinum compound in the metastatic setting, were eligible. Velapirib was administered orally, at doses of 400 mg twice daily. Dose adjustments based on toxicity were permitted. Patients progressing on velapirib alone received carboplatin at an AUC of 5, IV, given Q 21 days, and velapirib 150 mg twice daily (the maximum tolerated dose [MTD] of the combination from our completed Phase I study: J Clin Oncol 30, 2012 [suppl; abstr 1024]). Patients were to be accrued from 7 NCI NO1- supported consortia. Initially 10 patients were to be accrued to each stratum (BRCA1 and BRCA2) to provide evidence of single agent activity. If there was sufficient activity to warrant consideration of velapirib as single agent therapy (defined as 2 or more confirmed partial [PR] or better responses out of 10 per stratum), an additional 12 patients would be accrued per stratum. Results: 20 evaluable patients (11 BRCA1 and 9 BRCA2 [1 in screening]) have been accrued, the majority with lung or liver as visceral metastatic sites of disease. Median age (range) is 46 (29-68) years. Tumors from 9 patients were hormone receptor positive. BRCA1 cohort: 4 of 11 patients are off treatment at a median of 2 months (1-4); 1 patient stopped velapirib due to toxicity (grade 2 rash/pruritus, grade 2 vomiting), 3 stopped for progressive disease (one with an unconfirmed PR). Seven patients are still on single agent veliparib with 1 unconfirmed PR, and 1 patient with two evaluations showing stable disease. BRCA2 cohort: 2 patients are off treatment at 2 months for progressive disease, 7 are still on treatment with 1 confirmed PR, and 3 unconfirmed PRs. Data on patients receiving combination of velapirib and carboplatin after progression is too early. Treatment-related toxicity is being updated and has so far been reported from 14 patients: 1 patient had grade 3 fatigue, 1 patient with liver metastasis had both grade 3 alanine aminotransferase elevation and grade 3 abdominal pain. Grade 2 toxicities occurring in more than 1 patient included nausea/vomiting (6 patients), chills (2 patients), and fatigue (2 patients). Conclusion: Velapirib has single agent activity in both BRCA1 and BRCA2-associated stage IV breast cancer patients, and is well-tolerated. Mature response, treatment, and toxicity data will be presented.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-05.

Hereditary leukemia due to rare RUNX1c splice variant (L472X) presents with eczematous phenotype

Deleterious mutations in the RUNX1 gene cause hereditary leukemia due to a rare syndrome called Familial platelet Disorder with Associated Myeloid Malignancy (FPDMM). We describe the characteristics of a family with FPDMM due to a novel RUNX1 mutation (L472X), located in the most 3-prime end of the gene reported to date. Our 36-year old proband presented with incidentally detected thrombocytopenia and a family history suggestive of FPDMM. Contrary to previously described families, affected members of our kindred express an eczematous phenotype, reportedly most severe in members who develop leukemia. Pedigree analysis shows that the L472X mutation tracks with thrombocytopenia, acute leukemia, and eczema. The L472X mutation produces a stably expressed RUNX1 protein product with a corresponding decrease in wild type RUNX1 expression. Our data supports the inclusion of eczema in the FPDMM phenotype and suggests the possibility that the RUNX1 L472X mutant causes the type of dominant negative affect that is associated with an elevated risk of leukemia in FPDMM families.

Honoramos A Todas Nuestras Madres Con El Don Del Conocimiento: A Conference To Learn the Needs of Latina Patients and Families Seen for Breast Cancer Risk Assessment

Background: Long-term follow-up surveys of Spanish-speaking Latina patients at increased risk for hereditary breast cancer who completed genetic cancer risk assessment (GCRA) in our underserved clinics revealed a need for ongoing education and support. Consequently, we invited patients back for a half-day educational conference, employing mixed methods research to better understand their medical and social/cultural issues and needs.Aims: The conference aims were to: 1) share medical advances in GCRA and cancer screening and prevention recommendations and resources and 2) explore GCRA-related experiences and needs, and access to risk-appropriate care.Methods: Invitees were Latina patients with personal and/or family history of breast cancer who completed GCRA between 2001-2009 and their family members. The conference, conducted entirely in Spanish, was held at the regional county medical facility where our underserved clinic is conducted. Educational information was delivered by podium-presentations, expert and patient panel discussions and interactive sessions and community resource booth exhibits. Mixed methods research (surveys and Audio Response System [ARS] mediated interaction and discussion) was used to explore GRCA experiences and access to care.Results: The 71 primarily Spanish speaking (96%) participants ranged in age from 18 to 71 years (mean age, 44), were female (93%), had children (78%), and had at least completed high school (71%). Of the 41 patient-participant, 78% were accompanied by at least one family member and/or friend. Thirty (73%) had a personal history of breast cancer; 4 also had ovarian cancer. Of the 35 tested, 20 (57%) were BRCA positive. Nearly all participants (96%) completed the voluntary survey and post-conference evaluation. On average, 87% responded to eight ARS questions related to the GCRA process and access to care. The majority of patient-participant (71%) understood why they were referred for GCRA, 15% did not, and 13% were uncertain. Eighty percent understood their cancer risk; however 20% expressed a need for more risk information. Although 83% understood cancer screening recommendations, 17% were unsure and requested more information. Interestingly, only 5% reported lack of access to care. More than 75% found the GCRA process stressful and desired more support and preparedness for sharing information with relatives. All responders (96%) reported that the conference met their expectations, valued the resources provided, and suggested allocating more time for questions in a future conference.Conclusion: The interactive conference format was highly rated and effective in providing Latina breast cancer patients and family members with ongoing education and support following GCRA, and provided important information to guide improvement in the risk assessment process.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3073.

Magnetic Resonance Imaging quantification of breast density in BRCA carriers following gonadotropin releasing hormone agonist (GnRHA)-based hormonal chemoprevention

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Background: Breast tissue density limits the usefulness of mammography as a surveillance tool in young women. Breast Magnetic Resonance Imaging (MRI) provides high tissue contrast and three-dimensional structural information not impaired by high breast density. We developed a volumetric “MR density” measure of breast structural composition that may be complementary to mammographic breast density. We tested this MR density measure in unaffected women with known high risk of breast cancer due to a BRCA gene mutation (or empiric risk > 30% lifetime), who were recruited in a phase II trial to study the effects of a hormonal chemoprevention regimen. Methods: Nine premenopausal high-risk women age 21 to 48 were treated with intranasal GnRHA (deslorelin), low-dose estradiol, and testosterone daily for 10 months. All patients underwent one contrast-enhanced breast MRI exam before and after treatment. We measured MR density as the ratio of fibroglandular tissue volume to total volume of the breast, at both time points. Our technique involved the semi-automated delineation of the breast and the automated segmentation of fibroglandular from adipose tissue. An “MR index” was also defined to quantify partial voluming effects due to the presence of adipose/fibroglandular edges in the MR data. Results: Eight out of nine patients showed a reduction in MR density (p = 0.026) with treatment. Three patients had less than 5% MR density at baseline, making it difficult to quantitate a change with treatment. All of the remaining six patients had reduced MR density after treatment (mean reduction 35.5%; p = 0.035). Conclusions: We have demonstrated the use of breast MR density as a robust volumetric quantitative measure of breast tissue composition. Our findings suggest that MR could be used to measure hormonal chemoprevention effects in BRCA carriers.

[Table: see text]

Rapid progression of prostate cancer in men with a BRCA2 mutation

Men with BRCA2 mutations have been found to be at increased risk of developing prostate cancer. There is a recent report that BRCA2 carriers with prostate cancer have poorer survival than noncarrier prostate cancer patients. In this study, we compared survival of men with a BRCA2 mutation and prostate cancer with that of men with a BRCA1 mutation and prostate cancer. We obtained the age at diagnosis, age at death or current age from 182 men with prostate cancer from families with a BRCA2 mutation and from 119 men with prostate cancer from families with a BRCA1 mutation. The median survival from diagnosis was 4.0 years for men with a BRCA2 mutation vs 8.0 years for men with a BRCA1 mutation, and the difference was highly significant (P<0.01). It may be important to develop targeted chemotherapies to treat prostate cancer in men with a BRCA2 mutation.

Characterization of a novel founder rearrangement mutation of BRCA1 in high-risk Hispanic families

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Background: Large rearrangements are estimated to account for 5–10% of all mutations in BRCA1 and BRCA2. Prevalent founder rearrangement mutations have been described in European populations. We sought to identify rearrangements in the BRCA genes in a cohort of Hispanic patients. Methods: We identified 34 deleterious BRCA mutations via full sequence analysis among 110 unrelated high-risk Hispanic families enrolled in an IRB approved registry who underwent cancer risk assessment (CEBP 2005;14:1–6). DNA from 67 of 76 patients without an identifiable mutation was subjected to multiplexed quantitative differential PCR (MQDP, per B. Erickson and T. Scholl, Myriad Genetics Laboratory) for detection of large rearrangements. An apparent deletion of BRCA1 exons 9–12, indicated by a 50% loss of signal was identified by MQDP in 3 unrelated families (ASHG, 2005). Long range PCR resulted in the generation of a 2.7kb product in these samples, consistent with a deletion event of 15.1kb. This putative mutation was further characterized by cloning and sequencing the breakpoint in all 3 families. RNA splicing was evaluated by sequencing RT-PCR products from lymphoblastoid cell line RNA for each family. Results: Sequence analysis identified the breakpoint within Alu elements in introns 8 and 12, and all 3 unrelated families shared the same breakpoint. Analysis of cDNA demonstrated direct splicing of exons 8–13 predicting a frameshift mutation and premature truncation of the BRCA1 protein, thus confirming the deleterious nature of this mutation. Conclusion: We identified the same novel large deletion in three unrelated families of Mexican ancestry, suggesting potential founder effect. The frequency was 2.7% of the 110 high-risk Hispanic families screened for BRCA mutations, bringing the overall prevalence of deleterious mutations to 33.6%(37/110) in this cohort. This BRCA1 rearrangement may account for a substantial proportion of high-risk Hispanic families, and should be included in all subsequent studies of this ethnic group.

No significant financial relationships to disclose.

Comparative sequence analysis of the MECP2-locus in human and mouse reveals new transcribed regions

Comparative sequence analysis facilitates the identification of evolutionarily conserved regions, that is, gene-regulatory elements, which can not be detected by analyzing one species only. Sequencing of a 152-kb region on human Chromosome (Chr) Xq28 and of the synthenic 123 kb on mouse Chr XC identified the MECP2/Mecp2 locus, which is flanked by the gene coding for Interleukin-1 receptor associated kinase (IRAK/Il1rak) and the red opsin gene (RCP/Rsvp). By comparative sequence analysis, we identified a previously unknown, non-coding 5' exon embedded in a CpG island associated with MECP2/Mecp2. Thus, the MECP2/Mecp2 gene is comprised of four exons instead of three. Furthermore, sequence comparison 3' to the previously reported polyadenylation signal revealed a highly conserved region of 8.5 kb terminating in an alternative polyadenylation signal. Northern blot analysis verified the existence of two main transcripts of 1.9 kb and approximately 10 kb, respectively. Both transcripts exhibit tissue-specific expression patterns and have almost identical short half-lifes. The approximately 10-kb transcript corresponds to a giant 3' UTR contained in the fourth exon of MECP2. The long 3' UTR and the newly identified first intron of MECP2/Mecp2 are highly conserved in human and mouse. Furthermore, the human MECP2 locus is heterogeneous with respect to its DNA composition. We postulate that it represents a boundary between two H3 isochores that has not been observed previously.

Identification of H, K, and N-ras point mutations in stage IB cervical carcinoma

OBJECTIVE

The ras oncogenes, Harvey (H), Kirsten (K), and neuroblastoma (N), are a family of genes coding for a membrane-associated protein (p21) which possesses inherent guanine triphosphatase (GTPase) activity. Point mutagenesis at codons 12, 13, and 61 has been implicated in ras activation and subsequent cellular transformation. Given the epidemiologic relationship of HPV infection with cervical carcinoma and the tumorigenic interaction of HPV and mutated ras oncogenes, this study was undertaken to identify if mutated ras oncogenes were present in early invasive cervical carcinomas.

METHODS

A combination of polymerase chain reaction (PCR) and dot-blot hybridization was used to determine the frequency and types of ras point mutants occurring in cervical carcinoma. Thirty-three patients with early-stage cervical carcinoma were identified. DNA was extracted from archival tumor samples. ras genes were PCR amplified using flanking primers and hybridized with a series of labeled allele-specific oligonucleotides corresponding to wild-type forms of K12,61, N12,13,61, and H12,61, as well as to all combinations of substitution mutations (7 wild-type, 45 mutants).

RESULTS

ras mutations were identified in 24.2% of specimens. The detected mutations in H, K, and N-ras all occurred at codon 61. This was not the result of PCR or hybridization artifact in that mutations were detected in position 12 and 13 in appropriate control samples.

CONCLUSIONS

Mutant ras has been shown to convert HPV immortalized keratinocytes to the tumorigenic state. Our results indicate that a significant percentage (24.2%) of these early-stage cervical cancers contain activated ras. Additional studies will be needed to evaluate whether codon 61 represents a characteristic "hot-spot" of ras mutation in a subset of cervical carcinoma.

Clinical and research issues in breast cancer genetics

Breast cancer is the most common form of cancer in women in the U.S. The risk factors for developing breast cancer include increasing age, a family history of breast cancer, and the lack of a child by age 30. A substantial fraction of breast cancer, however, occurs in women who have no identifiable risk factors. The diagnosis, pathology, treatment, and presymptomatic testing of cancer susceptibility genes are reviewed. Syndromes with an associated risk of breast cancer are described, such as hereditary breast-ovarian cancer syndrome, Li-Fraumeni syndrome, ataxia telangiectasia, and Cowden's disease. With the localization of the BRCA1 gene to chromosome 17q21 and the BRCA2 gene to chromosome 13q12, issues surrounding breast cancer susceptibility genetic testing are assuming an ever greater measure of importance. The sensitivity and specificity for molecular testing of cancer susceptibility genes, however, have not been well defined. The progress in presymptomatic genetic testing is further hampered by various factors such as the technical difficulty in distinguishing mutations from polymorphisms, the number of different mutations identified thus far and the possibility of false positive and false negative results. Laboratory quality assurance/quality control issues are of paramount importance to avoid misleading interpretations. Many issues surrounding genetic screening and testing, such as insurance and employment discrimination, privacy, and informed consent, are under active debate, and guidelines and standards are under active development. It is therefore important to proceed with caution, so that irreversible harm resulting from data misinterpretation can be avoided.

Metastatic renal cell carcinoma to the right cardiac ventricle without contiguous vena caval involvement

We report an unusual metastatic renal cell carcinoma in the right cardiac ventricle in a 53-year-old man who presented with increasing dyspnea. Diagnostic evaluation revealed a left renal tumor without contiguous extension into the inferior vena cava and a right ventricular mass. To our knowledge this is only the second reported case of metastatic renal cell carcinoma to the right cardiac ventricle diagnosed ante mortem. We discuss the case and review the literature.