Abstract P4-04-12: Identification of a common genotype in patients (pts) with HER2-positive, ER-negative, inflammatory breast cancer (IBC) that was primary-refractory to trastuzumab who have had 5+ years of disease control with lapatinib therapy

Background: HER2-amplified inflammatory breast cancer (IBC) that is primary-refractory to trastuzumab has a poor prognosis. The objective of this study was to describe the genotypes of the IBC obtained from 3 pts with high grade, ER-negative, HER2+ classical IBC, primary-refractory to trastuzumab, with chest wall disease, who remain with no evidence of disease (NED) on lapatinib for 5+ years.

The 3 postmenopausal pts presented with locally advanced IBC, 2 with disease extending onto the chest wall, and the third with chest wall recurrence while on adjuvant trastuzumab. Two pts were treated with preoperative trastuzumab with multiple chemotherapy agents with no response. They were then treated with preoperative lapatinib and had a clinical partial response. They underwent salvage mastectomy showing extensive residual disease, followed by chest wall/regional radiotherapy (RT), continuing on lapatinib. The third patient received preoperative AC followed by docetaxel and had extensive residual disease at mastectomy. She underwent chest wall/regional RT and then had chest wall recurrence while on adjuvant trastuzumab. She was treated with lapatinib and resection of residual chest wall disease. All 3 pts remain NED on 1250mg lapatinib daily. The 3 pts have a strong family history of breast cancer; two have known wild type germline BRCA1/2.

Methods: Following IRB-approved informed consent, targeted next generation DNA sequencing (NGS) was performed using HiSeq-2000 (Illumina) on pts’ FFPE primary IBC at a CLIA-certified laboratory, to characterize all classes of genomic alterations across 4,604 exons of 287 cancer-related genes. Phosphoprotein analysis was performed using a proprietary Reverse Phase Protein Microarray (RPMA) platform on pts's FFPE IBC to characterize the activity of the targets of anti-HER2 therapy, and their downstream pathways.

Results: In 2 pts’ IBCs NGS identified a common genotype with amplified ERBB2, mutant p53 and PIK3CA (c.3140A>G_p.H1047R), homozygous deletions of both CDKN2A and CDKN2B, and truncated BRCA2 (1 pt) or PALB2 (1 pt). The third pt's FFPE residual disease from her mastectomy did not yield sufficient DNA from invasive tumor cells for sequencing and we plan to sequence DNA from her original diagnostic core biopsy. Phosphoprotein analysis of one pt's trastuzumab-refractory, lapatinib-naive IBC showed 3+ expression of HER1 (but not pHER1 Y1068 nor pHER2 Y1248), pAkt S473, pS6 ribosomal S235-236 protein (2+), p4E-BP1 S65 and Notch1. The second pt's lapatinib-treated IBC showed 3+ overexpression of only p4E-BP1 S65.

Conclusions: Pts with a common tumor phenotype who have highly durable responses with a targeted therapy may share a common tumor genotype. Two pts’ trastuzumab-refractory HER2+ IBCs that have been very durably responsive to lapatinib share p53, PIK3CA, p16 and BRCA2-related mutations, potentially enabling the prospective identification of trastuzumab-refractory IBC pts who may benefit substantially from lapatinib.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-04-12.

Association of HPC2/ELAC2 and RNASEL non-synonymous variants with prostate cancer risk in African American familial and sporadic cases

INTRODUCTION

The RNASEL and HPC2/ELAC2 genes have been implicated in hereditary prostate cancer. Further assessment of the role of these genes in sporadic prostate cancer in African American men (AAM) is warranted.

METHODS

Genotyping of HPC2/ELAC2 variants (S217L, A541T), along with RNASEL variants (R462Q and E541D) was completed in 155 African American sporadic and 88 familial prostate cancer cases, and 296 healthy male controls. Logistic regression analysis was performed and odds ratios (OR) were calculated, while correcting for both age and population stratification using admixture informative markers.

RESULTS

The HPC2/ELAC2 217L allele was significantly associated with risk of prostate cancer when taking all cases into account (OR = 1.6; 1.0-2.6; P = 0.03). The RNASEL 541D allele was associated with a decrease in risk of prostate cancer in sporadic cases (OR = 0.4; 0.2-0.8; P = 0.01). We did not detect an association between prostate cancer risk and the RNASEL R462Q variant. Results from haplotype analyses of the two RNASEL variants revealed highly significant differences in haplotype allele frequencies between cases and controls suggesting a synergistic effect at the RNASEL locus. One haplotype in particular (462R-541D) is far more frequent in our control population and shows a strong protective effect against prostate cancer (OR = 0.47, P = 8.1 x 10(-9)).

CONCLUSIONS

These results suggest that HPC2/ELAC2 and RNASEL may play a role, however minor, in prostate cancer risk among AAM.

Genome-wide linkage of 77 families from the African American Hereditary Prostate Cancer study (AAHPC)

BACKGROUND

The African American Hereditary Prostate Cancer (AAHPC) Study was designed to recruit families with early-onset disease fulfilling criteria of >or=4 affected.

METHODS

We present a approximately 10 cM genome-wide linkage (GWL) analysis on 77 families including 254 affected and 274 unaffected genotyped.

RESULTS

Linkage analysis revealed three chromosomal regions with GENEHUNTER multipoint HLOD scores >or=1.3 for all 77 families at 11q22, 17p11, and Xq21. One family yielded genome-wide significant evidence of linkage (LOD = 3.5) to the 17p11 region with seven other families >or=2.3 in this region. Twenty-nine families with no-male-to-male (MM) transmission gave a peak HLOD of 1.62 (alpha = 0.33) at the Xq21 locus. Two novel peaks >or=0.91 for the 16 families with '>6 affected' occurred at 2p21 and 22q12.

CONCLUSIONS

These chromosomal regions in the genome warrant further follow-up based on the hypothesis of multiple susceptibility genes with modest effects, or several major genes segregating in small subsets of families.

A common nonsense mutation in EphB2 is associated with prostate cancer risk in African American men with a positive family history

BACKGROUND

The EphB2 gene was recently implicated as a prostate cancer (PC) tumour suppressor gene, with somatic inactivating mutations occurring in approximately 10% of sporadic tumours. We evaluated the contribution of EphB2 to inherited PC susceptibility in African Americans (AA) by screening the gene for germline polymorphisms.

METHODS

Direct sequencing of the coding region of EphB2 was performed on 72 probands from the African American Hereditary Prostate Cancer Study (AAHPC). A case-control association analysis was then carried out using the AAHPC probands and an additional 183 cases of sporadic PC compared with 329 healthy AA male controls. In addition, we performed an ancestry adjusted association study where we adjusted for individual ancestry among all subjects, in order to rule out a spurious association due to population stratification.

RESULTS

Ten coding sequence variants were identified, including the K1019X (3055A-->T) nonsense mutation which was present in 15.3% of the AAHPC probands but only 1.7% of 231 European American (EA) control samples. We observed that the 3055A-->T mutation significantly increased risk for prostate cancer over twofold (Fisher's two sided test, p = 0.003). The T allele was significantly more common among AAHPC probands (15.3%) than among healthy AA male controls (5.2%) (odds ratio 3.31; 95% confidence interval 1.5 to 7.4; p = 0.008). The ancestry adjusted analyses confirmed the association.

CONCLUSIONS

Our data show that the K1019X mutation in the EphB2 gene differs in frequency between AA and EA, is associated with increased risk for PC in AA men with a positive family history, and may be an important genetic risk factor for prostate cancer in AA.

Clinical characteristics of African-American men with hereditary prostate cancer: the AAHPC study

INTRODUCTION

The African-American Hereditary Prostate Cancer (AAHPC) Study was designed to recruit African-American families fulfilling very stringent criteria of four or more members diagnosed with prostate cancer at a combined age at diagnosis of 65 years or less. This report describes the clinical characteristics of a sample of affected AAHPC family members.

METHODS

In all, 92 African-American families were recruited into the study between 1998 and 2002. Complete clinical data including age and PSA at diagnosis, number of affected per family, stage, grade, and primary treatment were available on 154 affected males. Nonparametric Wilcoxon two-sample tests and Fisher's exact test (two-tailed), were performed to compare families with 4-6 and >6 affected males with respect to clinical characteristics.

RESULTS

The mean number of affected men per family was 5.5, with a mean age at diagnosis of 61.0 (+/-8.4) years. Age at diagnosis, PSA and Gleason score did not show significant differences between the two groups of families. Based on the Gleason score, 77.2% of affected males had favorable histology. Significantly, there were marked differences between the two groups in the frequency of node-positive disease (P=0.01) and distant metastases (P=0.0001). Radical prostatectomy was the preferred primary therapy for 66.2% of all affected men followed by 20.8% who chose radiation therapy.

CONCLUSIONS

Our findings suggest that affected males who carry the highest load of genetic factors are at the highest risk for early dissemination of disease, thus efforts at early diagnosis and aggressive therapeutic approaches may be warranted in these families. Since the primary therapy choices in our study favored definitive treatment (87.0%) when compared to the 1983 and 1995 SEER data in which 28 and 64% received definitive treatment, respectively, it appears that affected African-American men in multiplex families may be demonstrating the reported psycho-social impact of family history on screening practices and treatment decisions for prostate cancer.

African-American heredity prostate cancer study: a model for genetic research

A genome-wide scan of high-risk prostate cancer families in North America has demonstrated linkage of a particular marker to Chromosome Iq (HPC11. An even greater proportion of African-American families have shown linkage to HPC 1. Therefore, investigators at the National Human Genome Research Institute [NHGRI] in collaboration with Howard University and a predominantly African-American group of urologists established the African-American Hereditary Prostate Cancer (AAHPC) Study Network to confirm the suggested linkage of HPC in African Americans with a gene on Chromosome 1. Blood samples from recruited families were sent to Howard University for extraction of DNA. The DNA was sent to NHGRI at NIH where the genotyping and genetic sequence analysis was conducted. Genotype data are merged with pedigree information so that statistical analysis can be performed to establish potential linkage. From March 1, 1998, to June 1, 1999, a total of 40 African-American families have been recruited who met the study criteria. Preliminary results suggest that racial/ethnicity grouping may affect the incidence and extent of linkage of prostate cancer to specific loci. The importance of these findings lays in the future treatment of genetic-based diseases.

African-American heredity prostate cancer study: a model for genetic research

A genome-wide scan of high-risk prostate cancer families in North America has demonstrated linkage of a particular marker to Chromosome 1q (HPC1). An even greater proportion of African-American families have shown linkage to HPC1. Therefore, investigators at the National Human Genome Research Institute (NHGRI) in collaboration with Howard University and a predominantly African-American group of urologists established the African-American Hereditary Prostate Cancer (AAHPC) Study Network to confirm the suggested linkage of HPC in African Americans with a gene on Chromosome 1. Blood samples from recruited families were sent to Howard University for extraction of DNA. The DNA was sent to NHGRI at NIH where the genotyping and genetic sequence analysis was conducted. Genotype data are merged with pedigree information so that statistical analysis can be performed to establish potential linkage. From March 1, 1998, to June 1, 1999, a total of 40 African-American families have been recruited who met the study criteria. Preliminary results suggest that racial/ethnicity grouping may affect the incidence and extent of linkage of prostate cancer to specific loci. The importance of these findings lays in the future treatment of genetic-based diseases.

Prostate carcinoma knowledge, attitudes, and screening behavior among African-American men in Central Harlem, New York City

BACKGROUND

Although the benefits of prostate carcinoma screening in reducing mortality rates have not been proven or shown to be cost-effective, screening, particularly using prostate specific antigen (PSA) tests, is widespread. A better understanding of screening behavior, knowledge of prostate carcinoma risk, and attitudes toward screening among men at high risk, such as African-American men, would be valuable.

METHODS

A prevalence survey was conducted using 2 samples of African-American men, aged 50-74 years: a clinic sample drawn from all clinics in Central Harlem (n = 404) and a random-digit dial sample from the same geographic region (n = 319). The prevalence of self-reported PSA screening was estimated using a cognitive survey methodology based on the internal consistency of answers to four different questions. Prevalence estimates were adjusted to take into account the high proportion of nontelephone residences.

RESULTS

The clinic sample, representing a poorer, more ill population (as determined by MOS Physical Function Scores, was less likely to report PSA screening than the community sample (11.1% in clinic sample vs. 25.5% in community). The prevalence of PSA testing in Central Harlem overall in this age group by using two different techniques was estimated to be 24%. In multiple logistic models, self-reported PSA screening was associated with age, education, favorable attitudes toward screening, and knowing someone who had prostate carcinoma. However, the association between these factors and the likelihood of self-reported PSA screening differed between clinic and community samples.

CONCLUSIONS

The prevalence of self-reported PSA screening in Central Harlem was lower than that reported for other populations. These findings may be useful in the design of health education campaigns and for counseling innercity, low-income African-American patients appropriately about the disease.

Recruitment experience in the first phase of the African American Hereditary Prostate Cancer (AAHPC) study

The African American Hereditary Prostate Cancer (AAHPC) Study is an ongoing multicenter genetic linkage study organized by Howard University and the National Human Genome Research Institute (NHGRI), with support from the Office for Research on Minority Health and the National Cancer Institute. The goals of the study are to: (i) look for evidence of involvement of chromosome 1q24-25 (HPC1) in African American men with hereditary prostate cancer (HPC) and (ii) conduct a genome-wide search for other loci associated with HPC in African American men. To accomplish these goals, a network has been established including Howard University, the NHGRI, and six Collaborative Recruitment Centers (CRCs). The CRCs are responsible for the identification and enrollment of 100 African American families. To date, 43 families have been enrolled. Recruitment strategies have included mass media campaigns, physician referrals, community health-fairs/prostate cancer screenings, support groups, tumor registries, as well as visits to churches, barber shops, and universities. By far, the most productive recruitment mechanisms have been physician referrals and tumor registries, yielding a total of 35 (81%) families. Approximately 41% (n = 3400) of probands initially contacted by phone or mail expressed interest in participating; the families of 2% of these met the eligibility criteria, and 75% of those families have been enrolled in the study, indicating a 0.5% recruitment yield (ratio of participants to contacts). As the first large-scale genetic linkage study of African Americans, on a common disease, the challenges and successes of the recruitment process for the AAHPC Study should serve to inform future efforts to involve this population in similar studies.

Antisense gene suppression against human ICAM-1, ELAM-1, and VCAM-1 in cultured human umbilical vein endothelial cells

Antisense gene suppression has been carried out for human ICAM-1, ELAM-1, and VCAM-1 in cultured human umbilical vein endothelial cells (HUVEC) stimulated by lipopolysaccharide, tumor necrosis factor alpha, or interleukin-1 beta. A panel of antisense phosphorothioate oligodeoxyribonucleotides (PS-ODN), complementary to mRNA or pre-mRNA of these molecules, were tested for their gene suppression activity monitored by radioimmunoassay of the respective cell surface adhesion molecules. Sequences targeted by effective antisense PS-ODNs were located throughout the mRNA and pre-mRNA. "Hot spots" of gene suppression sites for each region were observed. Shift of the PS-ODN hybridizing site upstream or downstream by a few bases resulted in drastic change of gene suppression efficiency. In addition to translation arrest and RNase H activity, a third mechanism was proposed for antisense gene suppression, involving multiple binding sites for PS-ODN and the activities of RNase H and RNases other than RNase H. Suppression of ICAM-1, ELAM-1, or VCAM-1 in HUVEC by their antisense PS-ODNs resulted in the reduction of adhesion of monocytes and U937 to HUVEC. This may suggest cooperativity among the adhesion molecule pairs in endothelial-leukocyte adhesion, since decrease of a single adhesion molecule on EC surface significantly reduced cell-cell adherence.

The presence of peptidoglycan-polysaccharide complexes in the bowel wall and the cellular responses to these complexes in Crohn's disease

Interestingly, using a monoclonal antibody, peptidoglycan-polysaccharide complexes (PPC) were detected intracellularly in the mucosa and submucosa of the bowel wall of Crohn's disease (CD) patients. PPC are the main constituents of the gram-positive bacterial cell wall. These PPC were however detected in the normal bowel wall also. Therefore, in this study the hypothesis that an enhanced immune responsiveness to bacterial antigens plays a pivotal role in the induction or the chronicity of CD was tested. As antigens, the peptidoglycan structures of intestinal bacteria (Eubacterium aerofaciens or fecal PPC) or of Streptococcus pyogenes, the 65-kDa heat shock protein and muramyl dipeptide (MDP), the smallest bioactive subunit of peptidoglycan, were used. The proliferative responses of peripheral blood (PB) mononuclear cells (MNC) of healthy subjects and patients in a remissive stage of CD or an active CD stage were examined. Of this last patient group the MNC responses of the mesenterial lymph nodes that drain the inflamed gut area were measured also. The responses of PB-MNC of the healthy subjects and the patients in a remissive CD stage were not different. Compared to the responses in remissive CD, the PB-MNC responses in active CD to the eubacterial cell wall and streptococcal cell wall antigen were significantly higher. At the inflammation site in active CD, the lymph nodes, the responses to most of the bacterial antigens were significantly higher than in the PB. In summary, the results show the presence of bacterial peptidoglycan in the bowel wall and the immune responsiveness, especially at the inflammation site, to these antigens in active CD and therefore present suggestive evidence for the role of peptidoglycan in the etiology and/or pathogenesis of CD.

Glycoprotein of human immunodeficiency virus type 1 synthesized in chronically infected Molt3 cells acquires heterogeneous oligosaccharide structures

Diversity of oligosaccharide structures on the glycoprotein of HIV-1 was studied in individual clones of Molt3 cells chronically infected with HIV-1IIIB. A glycoprotein of molecular weight 140 kD (gp140) was found to be shed into the medium from one of these clones, which unlike normally processed gp120, contained significant proportions of endo H resistant oligosaccharides. Treatment of infected cells with the inhibitors of oligosaccharide trimming enzymes affected the glycosylation pattern as well as the secretion of the glycoprotein into the medium. The exposure of the principal neutralizing domain (PND) on the surface of gp140, as measured by its accessibility to thrombin cleavage, was comparable to that observed with gp120. Sera obtained from mice inoculated with purified gp140 contained high titered anti-V3 antibodies and blocked HIV-1IIIB-induced syncytium formation. These results demonstrate that although glycosylation of viral glycoproteins is governed by the host cell glycosyl transferases, glycoprotein secreted from biological clones of the same host cells acquires different oligosaccharide structures. Exposure and immunogenicity of the PND in one such glycosylation variant are comparable to the normally processed gp120 molecule.

Characterization of a neutralizing monoclonal antibody to the external glycoprotein of HIV-1

The major neutralizing epitope on the external glycoprotein of HIV-1 was studied with an envelope-specific monoclonal antibody and with a human serum positive for antibodies to HIV-1 proteins, both of which were able to neutralize virus infectivity. The monoclonal antibody reacted specifically with gp120 from HIV-1IIIB, and was shown to neutralize infection of CEM cells by cell-free virions, and inhibited the formation of syncytia normally observed when uninfected cells are cocultured with HIV-1-infected cells. Similar neutralization of viral infection and inhibition of syncytia formation was also demonstrated by the HIV-1-antibody-positive human serum. By examining a number of overlapping peptides from a region of HIV-1 gp120 known to contain a neutralizing epitope, this epitope was localized between amino acids 307 and 320 (V3 loop) in the external glycoprotein molecule. The monoclonal antibody did not interfere with the binding of gp120 to CD4, or with the subsequent step of CD4-induced shedding of gp120 from the viral envelope. However, it blocked the proteolytic cleavage of the V3 loop by thrombin, suggesting that the antibody may be inhibiting the interaction of the loop with other membrane-bound proteins.

Effect of Evans blue and trypan blue on syncytia formation and infectivity of human immunodeficiency virus type I and type II in vitro

Polyanionic compounds were used to inhibit infectivity of human immunodeficiency virus in vitro. Suramin, Evans blue, and Trypan blue were shown to inhibit syncytia formation normally observed when HIV-1-infected cells are cocultured with CD4+ cells. The inhibition was more pronounced with Evans blue than with any of the other polyanions studied. The inhibitory effect was significantly weaker in HIV-2 systems. However, the reverse transcriptase activities of both types of viruses were inhibited by Evans blue. Another polyanionic compound, phosphorothioate 28-mer cytidine homopolymer (SdC28) was shown to inhibit syncytium formation induced by HIV-1-and HIV-2-infected cells in an identical manner. Evans blue showed partial blocking of gp120 binding to CD4 in a solid-phase enzyme-linked immunosorbent assay (ELISA). These results suggest that the polyanionic dyes may exert their antiviral effects, at least in part, by interfering with the binding and fusion of HIV with susceptible T cells.

Mode of action of 5'-linked cholesteryl phosphorothioate oligodeoxynucleotides in inhibiting syncytia formation and infection by HIV-1 and HIV-2 in vitro

A phosphorothioate homocytidine 10-mer containing a cholesteryl moiety covalently linked to the 5'-end (Chol-SdC10) inhibited syncytium formation in susceptible T cells induced by HIV-1 and HIV-2. The syncytium inhibition effect was minimal with unmodified cytidine homopolymer of the same net charge. Chol-SdC10 was shown to protect CEM cells against infection by cell-free HIV-1 particles without any apparent toxicity to the growth of CD4+ T cells. The DNA polymerase activity of the purified reverse transcriptase (RT) of HIV-1 was markedly inhibited by Chol-SdC10 but the effect on the RNase H activity of RT was minimal. Analysis of the kinetics of reverse transcriptase inhibition mediated by the drug revealed that the inhibition at a higher concentration was competitive with respect to template primer binding and noncompetitive at lower concentrations. Chol-SdC10 also partially blocked the binding of gp120 to CD4 in a solid-phase ELISA. These results confirm that the anti-HIV activity of phosphorothioate cytidine homopolymers increases markedly by covalent modification with the cholesteryl moiety at the 5'-end and demonstrates that the cytoprotective effect is manifested at multiple steps in the virus life cycle. These steps include inhibition of retroviral replication activity as well as the binding and fusion of HIV with CD4+ T cells.

Immediate induction of c-fos and c-myc transcripts following unilateral nephrectomy

Unilateral nephrectomy in the rat results in contralateral compensatory renal growth. The immediate molecular events which occur in the remaining renal unit were studied by examining RNA isolated from these kidneys. Northern blot analysis was used to analyze the expression of the growth-related (c-fos and c-myc) genes during the 1-hour period following unilateral nephrectomy. Both c-fos and c-myc band transcripts were detected within 15 min after nephrectomy. The immediate, transient induction of these genes in the remaining renal unit mimics that seen during proliferative stimulation of cultured cells and may play a role in modulating the eventual compensatory growth response.

Gene expression in response to acute unilateral ureteral obstruction

Acute unilateral ureteral obstruction results in differential growth characteristics of both the ipsilateral and contralateral kidney. The obstructed kidney undergoes cellular atrophy following an initial phase of interstitial proliferation while the contralateral kidney hypertrophies. To evaluate the molecular events occurring in both kidneys after obstruction, we examined the expression of growth related (c-fos, c-myc, cH-ras, HSP 70), cell maintenance (beta-actin), and cellular damage (TRPM-2) genes at the mRNA level. In the contralateral kidney an early and transitory induction of c-fos and c-myc expression occurred while a bimodal induction was noted in the obstructed kidney. The patterns of cH-ras, HSP 70 and actin expression also differed in both kidneys. Induction of TRPM-2 was noted only in the obstructed kidney. Rapid gene activation is evident in both the contralateral and obstructed kidney following unilateral ureteral obstruction. The patterns of expression are distinct and may reflect the cellular response to stress (cell death and stromal proliferation) in the obstructed kidney versus a response to a systemic stimulus resulting in cellular hypertrophy in the contralateral kidney.